August 28, 2020
by chris

South Sandwich Islands winter view

I have shown both summer and winter images of the South Sandwich Islands here before but a recent good weather window offered an opportunity for a much better winter view based on Sentinel-2 data.

South Sandwich Islands in Winter 2020

Sea ice extent is pretty far north this year, it often in winter ends somewhere between the islands but this year in the area reaches as far as 55 degrees north – that is further north than Cape Horn.

The image can as usual be found on the catalog on

August 20, 2020
by chris

Severnaya Zemlya in August 2020

Last week there were a few days of exceptionally good weather in parts of the Russian arctic and this allowed me to assemble a cloud free satellite image mosaic of Severnaya Zemlya – an archipelago i have featured here on the blog in the past – including a map which to this date remains the most accurate one of the islands available.

Severnaya Zemlya in August 2020

Clear views of the islands in summer are rare so the mid August window in this year has been the best opportunity for clear images for at least the last five years. The situation is also unusual in a different way. As you can see the Laptev Sea to the east of the islands is almost free of ice while there remains a significant amount of drift ice to the west on the Kara Sea. Historically in most years this is the other way round – the eastern coast of Severnaya Zemlya has in many years been enclosed by dense sea ice for most of the summer.

This image mosaic can be used to supplement the timeline of images of the Matusevich Ice Shelf and the Vavilov Ice Cap i have shown here before.

Matusevich Ice Shelf 2020

Vavilov Ice Cap 2020

Some more detail crops from the mosaic – which you can as usual find on

July 11, 2020
by chris

Conservatism, progressive and regressive change – framing in OpenStreetMap politics

A bit more than half a year ago i analyzed the political structure of the OpenStreetMap Foundation in the aftermath of the previous board elections. I identified two main factions within the OSMF membership – the craft mapping supporters and the corporate and professional interest faction. In terms of power balance these dominate the OSMF membership about 2:1. That is not representative for the OSM community obviously and as i pointed out back in the election analysis there are likely distinct other factions within the overall OSM community that are not adequately represented in the OSMF membership. Still, these two large factions are also present in the OSM community overall and their diverging views manifest frequently in policy related and other discussions.

I also pointed out that the craft mapping supporters are largely defined by a common set of values while the corporate and professional interest faction is defined through common interests. That is something to keep in mind in the following.

The reason why i revisit this topic now is that a new narrative has come up and is being communicated in the past months in OSMF politics – that is the need for change for OpenStreetMap and of conservative opposition from craft mappers against it. This narrative is largely coming out of the corporate interest faction and is framing the craft mapping supporters as conservative and opposed to any kind of change in principle and themselves as being the advocates of urgently necessary change. An OSMF board member has in public communication recently indicated to being inclined to adopt this narrative. I will get to that in more detail later.

What i did not discuss in my election analysis was how the factions i identified came into being historically. To get a realistic impression on the nature and the motivation of the different political movements in OpenStreetMap understanding the history of the project is paramount.

OpenStreetMap was founded and became successful largely because the existing situation of available cartographic data in many countries (in particular in Europe) was highly dissatisfying and disappointing for many people interested in maps. One part of the problem was that existing cartographic data producers, which were mostly government institutions, held a tight grip on their data making it difficult and expensive for everyone else to use it. But that was only one part of the problem. The more significant issue was that the data was poor quality for the needs of those using the maps. Poor especially in being an accurate representation of the local geography as perceived by the locals of the area. The reasons for that were largely that

  • the specifications to which the data was generated were decided by the needs of the institutional map producers who ultimately did not care about how accurately their data and data model represented the geographic reality and if it includes all the information relevant for the map users.
  • the technology and source data to produce cartographic data was kept under tight control by the mapping institutions where its broader availability could threaten their dominance on the market.
  • technical service companies and technology developers were working in a symbiotic relationship with the institutional map producers and due to that had no incentive for developing significant innovations or expanding their customer base in a way that might threaten that symbiotic relationship.
  • the actual data production was steered by cost efficiency so areas of low significance for economic and other institutional interests were typically extremely outdated.

As a reaction to this highly dissatisfying and severely deadlocked situation OpenStreetMap developed the approach to crowd sourced mapping that we all know today. Many of the fundamental principles of OpenStreetMap that the craft mapping supporters value today:

  • the focus on local knowledge,
  • the emphasis of OpenStreetMap as a social project and not merely as a collection of useful geodata,
  • the primacy of the local mappers and the local community of mappers in all decisions regarding mapping,
  • the free form and mapper centric tagging – not being designed for the needs of the data user but for convenience of and efficiency for the mapper,
  • the insistence on independence from any larger outside organizations, in particular w.r.t. any technology used for mapping,
  • the rejection of centralized decision making w.r.t. mapping and tagging,
  • the openness and transparency of all decision making processes

are a direct reaction to the described systemic issues of the cartographic data landscape the project faced when it was founded.

What happened then was that OpenStreetMap slowly but continuously gathered more interest among individuals to whom the premise of OpenStreetMap as a map by the people for the people appealed or who likewise felt the limitations of existing institutional cartography and wanted to participate in overcoming those. As OpenStreetMap grew and gained support among individuals, smaller businesses and startups, the cartographic institutions in different countries, as well as their customers (traditional map publishers as well as Google etc.), continued to ignore OSM – they were conservative in the sense that they were satisfied with the status quo in cartographic data and dreaded the risk of revolutionary changes. The individuals attracted by the project this way, as well as the businesses embracing and supporting the fundamental values of the project as described – and building business models around them – formed the core of the craft mapping supporters.

This continued until it became more and more inevitable for many cartographic data users to use OpenStreetMap data for economic reasons. This happened at different times for different data users – smaller companies and public institutions often being earlier than large corporations or big institutions. We have all seen for the past years many news headlines of prominent adoptions of OpenStreetMap. And this is obviously an ongoing process.

With the exception of some newly founded companies creating a business model explicitly around OpenStreetMap, very few of these late OpenStreetMap adopters actually wanted to use OSM data. Many in the OSM community have seen at one time or another some company trying to interact with the OSM community in a more or less clumsy way. The fundamental conflicts between typical corporate cultures and the social conventions of the OSM community are frequently discussed and fairly obvious. Many of these late OSM adopters would have very much preferred if OpenStreetMap was actually more like the institutional map producers – the shortcomings of which were the reasons OpenStreetMap was created and gained popularity. Of course preferably without the exorbitant license fees and the limitation to a national scope. And of course crowd sourcing work to reduce costs is perfectly fine as long as the volunteers are properly managed, based on the centrally defined needs of the stakeholders. These late and reluctant OpenStreetMap users who engage with the project not because they share its fundamental values but out of economic interests formed the core of the corporate and professional interest faction. That includes a large number of individuals who engage with OSM largely because they have or strive for a career in the domain of these commercial and institutional OSM data users.

It is important to keep in mind that the issues OpenStreetMap faced when it was founded are not overcome today, not by a long shot. In some countries institutional cartographic data producers have opened at least some of their data to the general public without artificial economic barriers but, as explained above, these barriers are only one of the things OpenStreetMap strives to overcome. The other thing that OpenStreetMap has accomplished is mainly breaking the dominance of centrally managed and non-inclusive data production steered by special interests instead of the needs of the people. But this accomplishment is fragile and will not last without ongoing commitment to the values of craft mapping described above.

I have talked to and listened to craft mappers and craft mapping supporters about their motives for supporting and emphasizing the traditional craft mapping values in a lot of cases and i rarely see anyone supporting these values due to a traditionalist, conservative attitude, in other words: who want to stick to these principles for their own sake and for stability and continuity itself. The vast majority of craft mapping supporters subscribe to the goals of fully democratizing cartographic data production. They see these principles as necessary parts of bettering our society in the way we manage and share our collective human knowledge of the world geography. In other words: The supporters of these traditional principles of OpenStreetMap support them as part of a shared truly progressive agenda in the original sense of the word. Many of them fight everyday for this goal and to overcome the issues and biases of institutional map production. Many of them would feel deeply insulted by the fact that their progressive values – which prove their usefulness and importance daily – are viewed by board members of the OSMF, who are meant to and have been elected to defend the values of the project, as a mere conservative clinging to traditions for their own sake and resisting change for no good reason.

The above illustration is remarkable and frankly a bit shocking because it fully adopts the views of the corporate and professional interest faction in disregard of the historic context as explained above.

What the above illustration does is fairly perfidious framing. It is titled “extreme positions” implying that it contrasts extremes on both ends of the political spectrum. But then if you look at the words used it is clear that the author – consciously or subconsciously – favors the right side and presents it as less extreme. Terms used on the left side imply radicalism (only, total) while the wording on the right side imply moderation (some, adapters) and concern (need, risk). If you wonder about the colors used – those match the colors of the US two party political system – red for the Republicans, blue for the Democrats. That fits the framing of the craft mappers as conservatives. The irony is of course that in Europe and elsewhere red is traditionally the color of socialist political movements.

To be clear – i do not just read things into a single, innocent slide taken out of context from a whole presentation here. Nowhere in the whole talk is there an acknowledgement of the present day relevance of the fundamental principles and values of craft mapping for the future of the project, values that OpenStreetMap as described above was founded on and that remain meaningful and essential to this day.

It is quite annoying to see corporate lobbyists pushing for example for automated data generation tools they designed and control, refusing and ignoring an open argument-based discourse on these, but then claiming that craft mapping supporters reject technological innovation in mapping in general. That is at best ignorant, at worst dishonest. But what’s more important – it is quite worrying to see OSMF board members subscribing to this narrative despite there being evidence in plain sight that this is wrong.

The sad thing for craft mapping supporters is not only that their progressive values are dragged into the mud but also that following the agenda of regressive, reactionary change of the corporate and professional interest faction would essentially mean rolling back what craft mappers through hard work have accomplished during the past 15 years. The main difference would be that control over cartographic data and its recording methods would no more be in the hand of government institutions on a national or subnational level but would be centrally managed on a global level largely in the interest of corporate data users with global ambitions.

I am aware that the above historical outline is much easier to understand for readers from Europe and other countries where the existence of monopolist institutional map producers formed and still forms a strong motivation for engagement in OpenStreetMap and for supporting its goals and values. In countries with either no dominant institutional cartographic data collection or where this is performed in a more open and more diverse fashion, this is much more difficult to understand without the first hand local experience. And i deeply sympathize with that difficulty. But it would be highly regrettable if other parts of the world could not learn from the painful experience we have made in some countries of Europe without making essentially the same mistake and letting cartographic data collection become dominated and controlled in a centralized, non-democratic fashion largely in disregard of local needs and local knowledge. And since OpenStreetMap is a global project it would not even be possible to let local communities newly learn this lesson without dragging the rest of the world into equally repeating history.

At the beginning of this post i linked to my after election analysis of the previous OSMF board election where i identified the two large political factions in the OSMF membership. In that same text near the end i also explained what i perceived to be the main challenges for the board this year, one being to embrace the more parliament like nature of the board which means having more open and constructive debate about the best decisions and engaging in open arguments with each other and the community about values, strategy and decisions. I emphasized this and the importance of a broad argumentative discourse on the merits of policy ideas later in comments. Unfortunately during the first half of this year the opposite seems to be the case. The board is more and more moving their deliberation on decisions into closed meetings and seems less and less willing to defend their plans and decisions in public discussion. Most board members have almost fully withdrawn from public two way discussion on OSMF politics on channels with a public record. Instead new closed formats have been introduced where the board confers with organized interests rather than individuals. The number of cases where in public board meetings there has been a substantial exchange of arguments w.r.t. a contested decision is minimal now. This is not a healthy development. The results – as they can be observed in the talk linked above – are not the product of malicious intent, they stem from views developed within the relatively narrow scope of the people on the board and who the board consults which misses a broader critical scrutiny through the whole diversity of knowledge and experience in the OSM community.

My advise to the board is to reconsider that direction. Making decision might seem to be easier if you take a more selective view and only listen to people you are comfortable listening to. But that is not a sustainable path. You don’t have to listen to my advice if you don’t like to but you should definitely subject your considerations and your reasoning behind decisions to critical evaluation also and especially from sides and viewpoints that you dislike, disapprove or simply are not aware of. The best way to do that is public scrutiny open to everyone and engaging in argumentative discourse with people who question your reasoning and decisions but if you have other ideas to do that feel encouraged to explore them as well. However having public consultations on position papers and interpreting the comments received like the results of a survey is not a substitute for actively engaging in an open struggle of arguments for finding the best decision.

But i also want to appeal to the craft mappers and the craft mapping supporters to always diligently communicate why and how the principles you value are important for the goals and the future of OpenStreetMap. Even if that seems self evident for you, it is not always for everyone else. I have done that on various occasions here on the blog and in many discussions elsewhere, but it is important for everyone to do this actively. And while this is relatively clear and undisputed for the central values and principles i listed above there are of course also traditions in OpenStreetMap that are not in support of the goals of the project. Being willing to have an open discussion about those with people who bring up a differentiated critique (and not just a blanket decrial of craft mapping values) is likewise essential for OpenStreetMap staying a force for progressive change.

TL;DR: The framing of craft mapping supporters in OpenStreetMap as conservatives opposed to change is inappropriate given the historic context and present day work of craft mappers all over the world towards progressive change. It has been created by regressive, revisionist interests that would like to roll back the ongoing democratization of geographic knowledge and its collection OpenStreetMap stands for in pursuit of short sighted economic goals.

July 7, 2020
by chris
1 Comment

SotM 2020 – a few thoughts on the experiment

Last weekend has been the 2020 State of the Map conference – which did not take place like it was originally planned and as it has been conducted in the past years at a specific physical place (in this case Capetown, South Africa) but was done in a purely virtual distributed form across the internet.

I regard this change – forced by the pandemic situation we all struggle with these days in some form – as in a way a welcome disruption. Due to an outside event the powers-that-be have been forced to try something they would not have tried probably in many years to come otherwise.

The implementation of the virtual distributed conference as an afterthought on an originally planned physical single place event led of course to some flaws and inconsistencies in the practical setup and to not using the full potential of the virtual setting in all of its aspects. This is obviously owed a lot to the desire not to throw away work already done. The most obvious issue resulting from that approach is that the main conference program contained almost exclusively program items submitted by people under the original premise of a physical conference – or in other words: The chance to hold a talk at the virtual conference still depended on the willingness and ability of people to travel to South Africa and be there for the talk in person.

This means the conference in its program was not even remotely as diverse as it could have been it it had been set up as a distributed remote conference in the first place. This should IMO be kept in mind by everyone evaluating how SotM 2020 turned out.

I regard the whole event mostly as an experiment to test various techniques and methods and means of communication to have a virtual conference in the OSM context. This applies both to behind-the-scene infrastructure and the public interfaces. If the SotM WG documents and shares their findings publicly that could have use far beyond SotM for the OSM community.

Practical observations from the conference

The pads for collecting questions and comments on talks worked great. This is definitely a concept that could play a central role in future distributed conferences. Initially the questions were asked anonymously which has led in particular in case of Frederik’s talk to quite a lot of people making vile comments under the disguise of anonymity. It was later established that questions and comments should be signed. I also think that the use of pads could be extended to non-talk program items like self organized sessions.

general feedback pad of the conference – there was a similar pad for questions and comments on each of the talks

The attractiveness of the pads to a large extent comes from the real time capability (which is essential for a real time conference obviously) combined with the non-linear free form structure of the text (which contrasts pleasantly with most other real time communication channels that tend to have a strictly linear structure).

There are quite a few things that could be improved about the audio. This starts with the levels of the pause music relative to the talk audio levels and continues with reverberations in poorly dampened rooms of some presenters and feedback noise in some people’s audio setup. That is mostly a matter of sufficient testing and experience with setting up and adjusting equipment in a way that works well. That takes time from everyone involved obviously. This is the hardest the first time but gets easier once you gain experience. And i am confident with the corona virus crisis incentivizing many people to gain more practice in remote communication knowledge and experience in this field is much improving every day. More communication about how to ensure good audio recording and communication quality within the community, sharing experiences and techniques used, would definitely be helpful.

None the less what also became clear to me during the conference is that the willingness of people to engage in communication was very clearly in the order written conversation > audio communication > video. I think this is an observation to consider for any audio or video conversation in the OSM context. Video meetings might be very convenient for heavily engaged extroverted community members with a pre-existing prominence but for many people this can be a source of discomfort. And cultural and language barriers can be strongly emphasized by use of real time audio and especially video communication.

Comments on the talks

I have not watched all the talks of the conference so this is more a list of anecdotal observations than a complete review. All the talks of the main conference program were pre-recorded while the Q&A after the talks were live. The pre-recorded talks offered a lot of options for presenters which would not be available in a live conference talk and which were used very differently by the presenters. Ilya in his talk Send me a Postcard IMO showed the most innovative approach to this. Watching this talk is recommended to anyone who in the future might be in the position to pre-record a conference talk as a positive example.

Some of the talks i watched so far that i consider particularly interesting:

Allan’s American perspective on the political spectrum of OSM

Allan’s keynote Winds of Change in OpenStreetMap – While this did not provide much new information of substance to those following OSMF politics in general and who have read past statements from Allan on that subject, it seems to provide a valuable glimpse into the current mentality of the OSMF board regarding their work. Although Allan had a prominent disclaimer that these are his personal views and do not represent those of the board, it is quite clear from statements and actions of other board members that they see many of these things similarly. There is quite a lot of accurate analysis in the talk but also quite a few highly questionable selective perceptions, assumptions and conclusions. I might comment about some of those separately although it is not clear at this time if the board is currently willing to openly discuss the merits of their views and opinions on the OSM community and the future of the OSM project and on the OSMFs role and defend their views and conclusions on these matters in a public setting.

Frederik explaining OpenStreetMap

Frederik’s talk There might have been a misunderstanding… – As usual Frederik explains in a well understandable way many of the central aspects of the OpenStreetMap project which new contributors as well as data users often struggle with because they differ from what people are used to, either in other internet communities or in the world of geodata. Naturally, a lot of these frequently misunderstood aspects of OSM are also fairly controversial and this has – as hinted above – led to a lot of critical and in parts insulting comments on the talk by people who would like these things to change and for OSM to become more compatible with their expectations. What Frederik presents however is for the most part not wishful thinking – presenting how he would like OSM to be – but how OpenStreetMap actually works and functions based on knowledge derived from many years of practical involvement in the project. Other long term participants will largely be able to confirm that. So whether you like these aspects of OSM or not and in what direction you might want OSM to develop in the future this is a very useful talk to watch to understand how OpenStreetMap ticks.

Mikel mocking concerns about conflicts of interest of corporate employees in the OSMF

Mikel’s talk An Incomplete History of Companies and Professionals in OpenStreetMap – Essentially Mikel is painting corporate activities in OSM and their history in rosy colors while saying: just pay no attention to all the skeletons lying around here. A lot could be criticized about selective presentations of facts as well as factual and logical errors or about the technique of jokingly dismissing and ridiculing differentiated philosophical critique of the influence of corporate interests in OSM. Anyway – I think this is a valuable talk to watch to get a glimpse into the mindset of many corporate employees involved in OSM as part of or in relation to their job.

Janet explaining aid work in rural Tanzania

Janet’s talk Building mapping communities in rural Tanzania – challenges, successes and lessons learnt – I found this interesting because of a certain observation. In the beginning a number of specific non mapping related examples are shown of aid being given to people in rural areas of Tanzania for everyday life problems. And emphasis is admirably given to helping locals solving these problems themselves in a sustainable and independent fashion using locally available means. Yet when it comes to mapping and digital technology the same initiative (and from what i know also many other humanitarian mapping projects) critiquelessly rely on commercial services and proprietary tools and encourage locals to use and rely on those services and tools that increase and perpetuate dependence of local people on non-local corporations for their local mapping work instead of educating people in using open source technology and tools they can manage and control themselves.

To be clear, i am not at all saying that this talk in any way constitutes an example for particularly bad practice in that regard, on the contrary the examples shown illustrate a principal awareness of the issue that is missing elsewhere. But to me it demonstrates quite well how fundamentally different measures are applied to the goal of supplying aid in a way that enables locals to solve serious problems in a sustainable fashion outside the digital world and within it.

Ilya making a case for sending postcards in an innovative style video

Ilya’s talk Send me a Postcard – I mentioned his talk already above as an example for making innovative use of the possibilities pre-recorded talks offer. Beyond that this talk is also recommended because Ilya has, more than most other prominent figures in the OSM community, a realistic appraisal of the challenges of inter-cultural communication in the OSM community.

Susanne explaining different approaches to localize a mapper from their editing work

Susanne’s talk Analyzing the localness of OSM data – this was one of the talks of the academic track which i found intriguing because it discusses a bit about how to thoroughly approach a subject from a scientific perspective – critically evaluating the concepts you intend to study in your research (here the localness of data and contributions in OSM) and defining the terms you use before you actually engage in studies. It does not present much in terms of actual results so this initial and highly important part of scientific work plays a prominent role in the talk. Like most scientific works analyzing OpenStreetMap in some form this also does not question the scientific profession’s own preconceptions (prominently manifested in the unquestioned assumptions that there has to be an inherent advantage in geodata collected by professionals compared to collection by hobby craft mappers) but it otherwise shows a thorough and open approach to the subject. Knowing the economic constraints of institutional scientific research these days i don’t have high hopes that the ambitious plans sketched in the presentation will be implemented without shortcuts being taken that devalue the results. But the willingness to be thorough is visible.

Looking into the future of distributed OSM conferences

In my opinion this conference – which as explained i regard as kind of an experiment – shows a bit on how much unused potential exists in the idea of a distributed conference. If this potential is being used in the OSM context in the long term significantly depends on how much the OSMF, the SotM working group and both the wealthy and influential international OSM jet set as well as the traditional corporate supporters of SotM conferences are willing to abandon the dear tradition of expensive and wasteful flying around the world to meet at a single place in large numbers in favor of trying out new and more inclusive possibilities.

A few further ideas on what possibilities a virtual conference format could offer beyond what has been tried this year:

In a distributed conference the hurdle to submit a talk proposal would be much lower because it does not require a commitment to make an expensive travel to the conference location. I can already imagine people fearing the program committee might be drowned in submissions. The solution to that is to not think of this in terms of a physical conference. You don’t actually need to make a pre-selection of talks based on abstracts submitted, you can let people simply submit their pre-recorded talks. That would require more effort on the side of a presenter than submitting a bloomy abstract which would filter out any non-serious submissions. And assessing a talk based on scrolling through the video for a few minutes is much fairer than doing so based on just an abstract. So having the program committee select talks rather than abstracts is likely the better and fairer option for a virtual conference. Alternatively you could skip the selection of talks altogether and simply make all submissions accessible to the conference visitors. After all a virtual conference is not subject to the physical limitation of available rooms. That you might not necessarily be able to offer a moderated live Q&A for all talks is clear – but there are options to solve that with some creativity.

The other idea is that a virtual distributed conference might be set up not only removing the constraint to a specific place but also spread out the conference in the time domain. Time zone differences are a serious issue with an international real time online conference – this could be observed at SotM 2020 quite well. So why not forego squeezing the conference into two days but instead spreading it across something like one or two weeks. A few days before the beginning of the actual real time part of the conference you make available the pre-recorded videos for everyone to watch at a time of their choosing. And they have the option to comment and ask questions asynchronously then. The speakers of the talks then have also some time to consider the questions and comments carefully before there is a moderated real time video session where the written feedback is discussed and further real time discussion is possible. The whole thing could be wrapped up by an integrated mechanism to allow speakers to provide some followup to the discussion in the days afterwards.

Allan (with Gregory as moderator) during his self organized Q&A session

With Allan’s keynote we had already a demonstration during this conference giving a bit of a glimpse on how this might work. There was no Q&A immediately after the talk but there was a longer Q&A later in the evening in form of a self organized session. Conference visitors in addition to asking questions during the talk streaming could afterwards for several hours re-watch the talk using the re-live feature and ask further questions and make comments. It was a bit unfortunate that Allan did not have more time to more carefully read the questions and prepare more elaborate answers which could have been the basis for a more interesting live discussion or later followup comments. But overall i think it was already visible how a more slowly paced dialog between presenters and visitors of the conference could facilitate a more productive and meaningful discourse.

To wrap up this blog post two more things: I consider it a fortune that with moving the conference to a distributed setting the scholarship program was scuttled for this year. From what i have heard the selection has already been completed and was conducted more or less like in past years despite the fundamental issues i pointed out before without any increase in problem awareness being visible in the OSMF. Had the scholarship program been actually gone through and again several ten thousand Euros of OSMF money been spent under questionable circumstances like this i would have felt compelled to completely boycott the conference because of that.

For future distributed conferences (no matter if they have a non-virtual component or not) it should be fairly obvious (and others have pointed this out) that with the money in the past spent on financing questionable short term travel around the world for a handful of selected individuals a lot more people (likely a factor of 10 to 100 more!) could be enabled in participating in the conference by spending a similar amount of money to finance access of people all around the world to digital communication bandwidth and equipment to participate in the conference remotely. That can take the form of subsidizing mobile data packages for individuals for the duration of the conference or things like renting a conference room with high bandwidth internet for a local group of mappers – many options would be possible here.

Finally i want to applaud the organizers for building the whole setup of the distributed conference mostly on open source software and open platforms. As it has been pointed out there is still room for improvement here by not prominently featuring proprietary communication platforms like Twitter, Telegram and Slack but the intention and commitment to be open on the core infrastructure is well visible. This is admirable especially considering not all events in the OSM world or even the FOSS world that have been moved to a virtual setting due to corona show such a commitment.

It would not be the internet without cat content – Ilya’s cat is making an appearance

July 1, 2020
by chris

SotM 2020 artwork – projections and generalization pitfalls in symbolic maps

The State of the Map conference of 2020 has recently published two logo designs for T-shirts and stickers and i want to have a few comments on cartography and design of those here.

Although i don’t know when these designs have been originally developed they seem to kind of reflect the overall weirdness of the virtualized conference which – while the conference being completely non-physical – tries to maintain the impression and the characteristics of a localized physical event as much as possible and unfortunately IMO also retaining much of the exclusivity of a conference where the costs of participation for the average visitor would have been in the order of EUR 1000 or more. While the virtual conference is open for participation as visitors to anyone without charge the main program consists of talks only by people who were originally willing and able to travel to South Africa for that purpose. But that is subject for a different blog post. This one is about cartography.

The designs developed for the conference you can find here (developed by Bernelle Verster, CC-BY-SA 4.0):

official SotM 2020 T-shirt design

official SotM 2020 sticker design

The map projections

First of all it is refreshing to see that neither of these show a mercator map. That is promising and admirable considering the overwhelming dominance of the Mercator projection in the OpenStreetMap world where Earth is essentially a square and the vast majority of people who produce maps and the vast majority of OSM specific data processing tools for map production know nothing else.

So what map projections have been chosen here? The first one uses the Dymaxion or Airocean projection. This is a variant of the class of icosahedral projections which map the approximately spherical surface of Earth to an icosahedron and then cut this open in some fashion to create a flat map.

generic icosahedron projection

The Dymaxion projection is somewhat more complex than plain icosahedral projections because it in some cases does not only cut along the edges of the icosahedron but through the faces. Combined with an optimized rotation of the icosahedron this allows a continuous display of the land masses of Earth with no larger land areas being cut and the rather limited distortion of mapping the spherical surface to the icosahedron faces leads to a overall very low distortion map.

the Dymaxion projection

This projection also has a different distinctive property – it is an interrupted projection, meaning it has an edge far longer than half the circumference of the earth. There are other, more common interrupted projection like the following.

Example of other interrupted projection

The advantage of the interruptions is that they allow the map to combine low scale and shape distortions within the non-interrupted parts of the map. They however have the disadvantage of being completely unable to properly represent relationships across the interruptions. In case of the Dymaxion projection the interruptions are placed over the ocean and as long as the map user is only interested in land areas this is fine. Things like the proximity of Africa and South America across the Atlantic Ocean however are not properly represented.

Another property of this projection is that there is no alignment whatsoever to the earth rotational axis. Some consider this an advantage claiming the Earth is spherical and without any direction having particular significance. This however neglects the fact that the rotation of the Earth is of fundamental importance for the planet and a map projection where this is not taken into account is poorly suited to illustrate climate zones or other phenomena related to the Earth rotation.

For a South Africa conference logo this map projection is an interesting choice because South Africa is located at the far periphery of the Dymaxion map – opposite to the main axis of the map formed by the Pacific Ocean rim. I am not sure if this was a conscious choice of the designers but in a way the Dymaxion map very prominently celebrates the unique position of southern Africa on Earth.

There are a number of peculiarities in the actual image of the T-shirt design. One is a phantom island in the Pacific Ocean west of the Galapagos Island which does not exist in the real world. The other is the incorrect location of Kerguelen Island ad the upper edge of the map only about half the distance from Australia compared to its actual location.

The sticker design in a way goes into a completely different direction and uses an orthographic map projection with southern Africa at its center. This essentially is the appearance of the Earth from infinitely far away above this location. It shows half of the planet only obviously – which might make people from North America especially uncomfortable possibly.

As an additional quirk it uses approximately a south up orientation – which positions the Antarctic approximately where the logo covers the map.

Generalization pitfalls

The sticker map brings me also to the second topic of this post – the cartographic generalization pitfalls of designing maps like this. The problem you are dealing with here is that for a T-shirt or a sticker you do not want an excessive amount of detail, you want a clear map where the shapes of the geography are well recognizable. This is a standard task of cartographic generalization but unfortunately maps like this are rarely made by actual cartographers. The most obvious problems with the generalization used are that the Red Sea, the Mediterranean Sea and the Black Sea are degraded to lakes in the Sticker design. That is a big no-no in cartography (although we see this also in interactive online maps which are often designed by software developers which unfortunately often leads to a neglect of the cartographic side of things).

One other issue – which is unfortunately also fairly common in other small scale maps – is the inconsistency in what islands are shown and not shown on the map. The Dymaxion map displays Hawaii, Galapagos and even the South Orkney Islands but neither the Falkland Islands or the Lesser Sunda Islands or New Caledonia.

Neither of the maps probably use OpenStreetMap data as a basis – which is a bit ironic for an OpenStreetMap conference of course. They even seem to use a different data basis which is visible in the Antarctic where the Dymaxion map misses the Ross Ice Shelf but includes the Filchner–Ronne Ice Shelf while in the sticker map it is exactly the other way round. I hope this illustrates that taking care in data source selection and using accurate data of known and consistent quality is not something you can simply forgo when doing small scale illustrations. Though common practice already in pre-digital times picking a possibly decades old data set of unknown provenance out of convenience because it has already been preprocessed for your needs is rarely a good idea and often leads to replicating errors.

inconsistent rendering of the Antarctic in both maps

To demonstrate that and how these issues can be improved upon i prepared alternative versions of both designs. You can see and download them below. All of them are under CC-BY-SA like the original designs. Using ODbL OpenStreetMap data.

The projection of the sticker map is – although very similar – not completely identical and i produced different variations of the T-shirt design with different generalization levels and rendering styles of the coastline. Further individualization is encouraged.

I hope both the discussion of the issues with the maps in these designs and the demonstration of improvements to those help designers producing such illustrations understand better how quality cartographic work is at the core of any quality graphics design work involving maps. And maybe the few examples discussed here provide the interested reader a somewhat better idea of what constitutes quality in cartography in particular at small scales.

Sticker design with better generalization of the coastline based on OSM data (SVG)

Just the map without logo and text

T-shirt design with improved generalization – low detail version (SVG)

T-shirt design with improved generalization – high detail version (SVG)

T-shirt design with improved generalization – filled color version (SVG)

These are of course also examples of the map design and cartographic data generalization work that i am offering – if you have need for such services you are welcome to contact me about that.

June 20, 2020
by chris

Single symbol patterns in maps

I have written quite a bit both theoretically as well as practically about the use of pattern for area characterization in map rendering. Using either a pictorial or a structure pattern can help differentiating in the characterization of areas without the need to use an extensive and potentially confusing number of different colors and can be more intuitive than using colors alone as well.

Patterns that repeat the same symbol either in a random or a regular periodic arrangement are well suited for area shapes that vary a lot in size. The repetitive nature of the pattern makes sure that its characteristics can be identified even from just viewing a small part of a polygon.

pictorial and structure pattern for differentiating areas

When visualizing polygon shapes of relatively small and uniform shape and size however this advantage is less useful and in case of pictorial symbols the repeating symbol is kind of redundant and adds unnecessary noise in many cases. Traditionally therefore small polygon shapes in interactive digital maps are often visualized with point symbols for detailed differentiation. This however has also a number of disadvantages, in particular point symbols blocking each other or interfering with labeling.

blocking point symbols

One idea for a possible alternative is what i would call a single symbol pattern. This means essentially rendering a single point symbol for the polygon but not rendering it as heavy symbol above all polygon shapes and linework and blocking each other and labels but like a pattern as an extension or variation of the polygon fill.

The use case where i now have tried this idea on is sport pitches. In OSM-Carto sport pitches are rendered with a fairly heavy green tone illustrating the fairly specific nature of these features. But they are rendered all identically – independent of the kind of sport that is being practiced on the pitch.

One solution to illustrating the type of sport on pitches used by maps has been drawing line markings. In the OpenStreetMap context this has been done both manually by mappers mapping sport field markings explicitly with barrier=line – a practice that is not seen farourably by many mappers – or automatically, an idea first featured by the French OSM style and later in a variation compatible to varying map scales at different latitudes in the German style. This technique however has the disadvantage of being (a) only suitable for sports with a distinct line markings (b) difficult to read intuitively because the line pattern is kind of a code for the sport only readble by someone familiar with it and (c) it has the potential to be confused with other types of line signature in the style.

line drawings on the German style

Mapnik does not offer a technically simple and elegant way of rendering a single symbol pattern as a polygon fill. Obviously you can use a normal pattern that is very large with just one symbol in the middle and a lot of empty space around so it does not actually repeat in practical use. But this is neither elegant not does it offer a decent way of properly aligning the symbol. The technique i chose instead is using compositioning by first cutting out the pitch fill (using comp-op: dst-out) and then rendering just the pitches as a backdrop with the background fill and a point marker using comp-op: dst-over.

single symbol pattern rendering for soccer pitches

What i have also tried out with this change is enlarging the symbol to twice the size once the size of the pitch on the map allows this. This helps readability of the symbol especially in cases where there are labels overlapping the symbol (which as mentioned can happen since the symbol is non-blocking).

enlarged symbols for larger pitches

For the symbol design i chose the approach to visualize all sports uniformly with an illustration of a person performing the sport in question. This is a pretty widespread technique in sport symbology in general but in digital maps it is not that common so most of the symbols i had to develop from scratch. Having a uniform design concept avoids confusion and helps recognizing this group of symbols as a certain class within the map.

all the sports for which symbols have been added

As usual this change is available in the alternative colors style. More examples (all of which use ODbL OpenStreetMap data – like the other non-abstract examples above):

June 10, 2020
by chris

Satellite image recording limits

When i announced the Green Marble mosaic version 2 mosaic recently i mentioned that the land coloring is based on MODIS data while the water color is created from Sentinel-3 data. There are multiple reasons for this choice of data sources and one of them is that only very few of the earth observation satellites currently operating actually record the whole planet surface. I discussed recording limits of individual satellites in the past and here i want to take a more systematic look at the matter.

As i have mentioned on several occasions most earth observation satellites record their images from a sun synchronous orbit meaning that the orbital plane of the satellite rotates against the earth rotation and thereby the orientation of the orbit towards the sun and therefore the lighting condition as it flies along its path stays constant from orbit to orbit. To achieve this the satellite has to be at a specific orbital inclination depending on its altitude. Since the range of orbital altitudes of earth observations is quite narrow their orbital inclinations are also similar. The orbital inclination also defines on how far north an south the satellite flies. When i plot the latitude limit of the ground track of the satellite’s orbit i get the following for the most commonly used open data earth observation satellites.

Southern ground track limits of open data earth observation satellites

Northern ground track limits of open data earth observation satellites

The satellites with the VIIRS instrument (Suomi NPP and NOAA-20) have the highest orbit with about 834km which leads to the lowest latitude limit. The satellites with the lowest orbits are Landsat and the MODIS satellites (Terra and Aqua) at an altitude of slightly more than 700km.

The actual recording limit of the satellites is defined by this ground track limit plus half the width of the recording swath of the satellite. This leads to – as illustrated in the following – Sentinel-2 recording slightly further north and south than Landsat despite a higher orbital altitude. But for Landsat we also have the practice of off-nadir recordings made by having the satellite look slightly sideways. The limit of these recordings as they are routinely being made is indicated by the dotted line.

Southern ground track and recording limits of Sentinel-2 (red) and Landsat (violet) including off-nadir recordings (dotted)

Northern ground track and recording limits of Sentinel-2 (red) and Landsat (violet) including off-nadir recordings (dotted)

The situation becomes a bit more complicated with the lower resolution instruments. Both Sentinel-3 optical instruments record asymmetric views and therefore have different recording limits in the north and south – in the north their view reaches up to the pole meaning there is no recording limit while in the south you have the limits shown in the following illustration in blue. Further south is the limit of the GCOM-C SGLI intrument which has a symmetric view and therefore equal limits north and south.

Southern ground track and recording limits of Sentinel-3 (blue) and GCOM-C SGLI (violet) as well as pole overlaps of MODIS (dashed cyan) and VIIRS (dashed green)

Northern ground track and recording limits of GCOM-C SGLI (violet) as well as pole overlaps of MODIS (dashed cyan) and VIIRS (dashed green)

No limits in either north or south are shown for MODIS and VIIRS – these both reach beyond the pole on both sides. These are the only data sources available that currently offer a truly global coverage of the whole earth surface in the visible spectrum. What i show in the illustrations with a dashed line is the limit of overlap across the pole – within these circles twice as many images are recorded therefore.

What has to be kept in mind is that the satellite orbits as discussed in the beginning are all very similar and the different recording limits primarily result from the different recording swath widths. And the wider view satellites differ in resolution over their area of view quite significantly because at the edges the earth surface is much further away than in the center of the view. Hence even though the poles are recorded by some of the satellites the resolution of these recordings is not as good as it is at lower latitudes where the best available image is always much closer to a ground track of the satellite.

May 19, 2020
by chris

Corruption and OpenStreetMap

This post is about a topic that i have wanted to write about for a long time and that has recently due to various developments in OpenStreetMap and in particular the OpenStreetMap Foundation become much more significant. These development are in particular

  • the large scale donations the OSMF has received during the past two years.
  • The massive increase in the OSMFs inflow of money due to corporate memberships since 2016.
  • The corresponding increase in expenses of the OSMF, in particular as part of the SotM scholarships and the starting microgrants program.
  • The massive increase in paid activities – both mapping and others – within the OpenStreetMap project.
  • The increased presence and activity of employees of corporations with OSM interests within the OSMF – including attempts at taking systematic influence.

What i mean with Corruption

Upon reading the title of this post some might have scowled about the use of the nasty word of corruption. I therefore first want to explain what i mean with it and why i think it is not only appropriate but essential to use this term when discussing the matter.

What i mean when i talk about corruption is when power entrusted to someone for the common good is used for the benefit of special or private interests. The important thing to keep in mind is that corruption is often not generally illegal. There are acts of corruption like bribery or extortion that are often forbidden, at least on the side of the beneficiary, but there are also activities that fall under the above definition that are broadly accepted and even considered admirable as for example clever networking. What has in addition also led to cases of legal corruption is that policy in certain contexts (be that legislation in a country or small scale policy making for example in OpenStreetMap) has already been designed to serve certain special or private interests against the common good or has been specifically designed to allow and endorse corruption that is considered either harmless or beneficial by the powers that be.

A lot has been analyzed and written about practical corruption, its effects and its dynamics. Broadly accepted aspects of corruption are for example:

  • Existing corruption or even just the perception of it often breeds more corruption because people loose the confidence to be able to make progress without corruption.
  • As a result, the damage of corruption on a community is often much larger than the material damage directly coming from the benefits channeled away from the common good towards special interests.
  • Corruption frequently is a double awareness issue – people engaged in corrupt activities often do not consider themselves to be corrupt and people in a corrupt organization/community often don’t see the signs of corrupt activity as such.
  • Related to that corruption – while being ultimately a moral issue – is for those faced with its presence in a community – not a decision between good and bad but a real moral dilemma.
  • Money is the main catalyst for corruption but by no means the only way corruption can function.
  • Corruption tends to be highly resilient towards attempts to eradicate it where it happens – largely because it becomes deeply rooted in the attitudes and beliefs of people and these are very hard to change through imposed regulation or even through shifting social norms.

Businesses tend to have an ambivalent relationship to corruption. Someone working for a business being corrupt and serving external interests as opposed the overall interests of the business is obviously bad for it. But using corruption outside the business itself to benefit their private interests is at the same time something potentially useful and profitable.

Conflicts of interest and corruption as a compliance problem

That corruption is widely considered a nasty word has a lot to do with the ambiguous relationship our societies and in particular the business world has towards corruption. Because of that in the English language a term has been established as a less problematic code to talk about corruption – the conflict of interest. A conflict of interest is essentially a situation that might lead to corruption. This is more harmless to talk about and in the English speaking domain widely has been adopted as the more socially and politically accepted way to talk about rules and procedures for compliance with those rules without actually identifying and pointing out corruption happening. The actual corruption can stay hidden in the closet, so to speak, while procedures for conflict of interest handling can be pointed to for showing that you are doing something or to meet legal requirements.

  • Because the conflict of interest is not considered bad per se, procedures almost always call for mitigation and not for avoiding the conflict of interest. Mitigation however often does not reliably prevent corruption, it often moves corruption to less open channels where it is harder to identify and address.
  • Trying to identify conflicts of interest is almost always a perception problem. If you rely on people identifying their own conflicts of interest that usually does not work. See above for the fact that corrupt people rarely consider themselves to be corrupt and have limited or no awareness of the problem. External evaluation can help but is potentially subject to corruption as well.

Overall conflict of interest procedures can only help with corruption to some extent and will typically not prevent it reliably. And if such procedures are implemented with the aim of compliance only (with legal requirements for example) they can be counterproductive even because they can prevent other more effective measures against corruption.

Corruption in OpenStreetMap – why is it a problem

So given that corruption is not necessarily illegal and that legal requirements can be met by implementing procedures for conflict of interest handling why should it still be a problem for OpenStreetMap?

OpenStreetMap as a project of egalitarian cooperation of individuals has as such inherently a small surface of attack regarding corruption. But despite the egalitarian nature of the project on the social level in principle people have different roles within the project and such roles involve some people having various sorts of power entrusted to them. The do-ocratic system the OSM community is proud of (and which is often the basis of assigning power in OSM) is inherently prone to corruption because the ability of people to do things – the basis of the do-ocratic system – can often be massively influenced by outside interests and money. We see this on the level of mapping obviously, where organized and paid activities in many parts of the world account for a significant fraction of all mapping activities but we also see it on the development level, where many influential positions are filled by people who are paid by special interests.

This kind of corruption has the potential to completely undermine the very foundations of OpenStreetMap as a social project. If the volunteers in the project see that to accomplish something and improve things in the interest of the project they have (a) to primarily interact with people who are getting paid for their work by outside interests and (b) to fight an uphill battle against or need to align themselves with these special interests to accomplish things for the common good, that can be massively demotivating and will lead to in particular qualified people interested in the common good withdrawing from activities – or adjusting and becoming corrupt themselves.

Corruption as a central issue of the OpenStreetMap Foundation

In principle much more directly affected by the problem of corruption than the OSM community as a whole is the OpenStreetMap Foundation. At the beginning of this post i listed various material changes that more recently started contributing as strong driving factors for corruption in the OSMF. What however makes the problem much more drastic is the almost complete lack of problem awareness within the OpenStreetMap Foundation.

The OSMF board has recently adopted a new policy regarding conflict of interest handling that makes it explicit that they regard corruption purely as a compliance problem. What they essentially do is codify the status quo in looking at corruption risks (which is already questionable regarding legal compliance but is quite clearly insufficient regarding actual corruption prevention) and postulate it to be sufficient to satisfy British law. Beyond that there are no documented general measures for corruption prevention in the OSMF at all. In particular

  • there are no rules at all regarding what would disqualify someone for any position in the OSMF. Some of the working groups have their own rules for membership preventing people to become a member with an obviously high risk for corruption. But this is just tolerated by the OSMF board and such working groups sometimes are viewed with envy and resentment by the rest of the OSMF due to the higher level of trust they tend to receive from the community because they are being perceived as islands of integrity.
  • There is no independent oversight whatsoever or detailed transparency regarding money spending beyond the formal financial auditing – which again is regarded exclusively as a compliance issue. This equally applies to the purchase of IT infrastructure and services and to things like SotM scholarships. In the latter case, the OSMF board seems to even actively ignore the problem – dismissing responsibility and accountability for the spending of money by declaring a financial independence of the SotM working group.
  • The previous point is visibly not a problem of legacy structures maintained from a time when the OSMF and OSM were both much smaller but is a current issue grounded in either a lack of awareness or an unwillingness to act. This has become visible with the recently introduced microgrants program. This kind of money spending has inherently a very high risk for corruption as probably anyone can imagine. Yet the OSMF board in their framework has not formulated any rules as to how corruption within the microgrants program can be prevented. There are again no criteria what would disqualify anyone from playing any role in this program – be that in the committee tasked with selecting applicants (where most of the members have formal connections to external interests that could lead to corruption) or as an applicant or in some other role (translating texts, mentoring projects etc.).
  • Also otherwise there are no codified documentation requirements within the OSMF for decision making processes beyond the basic legal requirements of British corporate law. The board routinely deliberates and negotiates – also with lobbyists – about political decisions, even of significant economic and social reach, on non public communication channels without records and there are no rules requiring disclosure of such negotiations to the OSMF members. Where records likely exist (like for example for internal mailing lists of board and working groups) there are no rules for retention periods and access rights.
  • There is – and i have criticized that countless times already – a deeply rooted culture of non-transparency within the OSMF and the aversion to daylight of people within the OSMF seems to be increasing. Unfortunately this is a self emphasizing problem. When an organization increasingly performs work in secrecy, initiating transparency on specific things is increasingly perceived as inconvenient because it requires a lot of compartmentalization efforts from those involved. Looking only at the OSMF board you can observe for example while the volume of board decisions has increased from previous years quite visibly, the volume of public deliberation and discussion of these decisions has not. Most of the public communication of board activities now happens in an indirect, synthesized form through minutes and other selective reporting of activity that has happened in private, not through that activity itself being transparent.

These deficits alone however are not the main problem that worries me and that makes me conclude that corruption within and through the OSMF has the potential to be a massively destructive force in the OSM community in the future. What really worries me is that the OSMF has meanwhile and is continuing to separate itself from the OSM community in terms of social norms and values. I already mentioned the matter of transparency where the OSM community is accustomed to a very open work style in everything while the OSMF generally has a culture of working non-publicly by default. But there are other fields as well in which the OSMF increasingly makes decisions that lead to astonishment within the community. Such a widening social and cultural gap between the organization OSMF and the community whose interests and common good it is supposed to support nurtures the development of systemic corruption as within the organization special interests start being perceived to be identical with the common good.

There are a number of social factors that are likely to promote systemic corruption that i find present in the OSMF and to some extent also in the OSM community in general:

  • The increased presence of people, especially also in positions of power, who engage in OpenStreetMap as part of or connected to their professional careers – and due to that often have a lot to gain and to loose personally through their position. This inherently incentivizes corruption.
  • The rather limited level of awareness of the overall goals and values of the project in everyday work and the cavalier attitude of many towards them.
  • The apparently very small role ethics play in decision making in the OSMF in general. I am for example fairly staggered that in discussions of diversity in the OSM community, ethical considerations seem to be fairly alien to a large fraction of the people who contribute to the discussions.
  • The persistent dismissal and lack of awareness of the failure of the OSMF to proportionally represent the OSM community and its cultural diversity in its structures and decision making processes.
  • The lack of a culture of argument and constructive debate in decision making processes in the OSMF and that decisions are mostly regarded purely as matters of negotiation between different interests rather than a competition of arguments and reason.

What to do about it?

I am somewhat at a loss with how to substantially address these issues (without the nuclear option so to speak to bury the OSMF into insignificance) so i would welcome input from people with practical experience in fighting and preventing corruption, in particular in organizations in developed countries.

There are however a few suggestions that i would likely consider helpful measures:

  • Everyone involved in the OSMF should aim for transparency as much as possible. I would encourage anyone who is engaged in non-public OSMF processes of some form – be that within the board, the working groups, some committee or otherwise – to publish and report on what is happening beyond the officially presented record like minutes. Especially if you see signs of possible corruption, decisions being made and implemented that are likely more serving special interest than the common good of the OSM community. Or non-public attempts of influencing processes and decisions by special interests. Or the failure to address risks of corruption or other ways decisions are made and mechanisms work that are not in the interest of the OSM community. If you feel the social structures do not allow you to openly point out the issues you see, you can contact someone you consider trustworthy to disclose such things for you in anonymity.
  • If you feel like you can’t contribute in a certain context any more without betraying your values then withdraw from that field. I have in the past encouraged people to involve themselves in the OSMF where they think they can productively contribute and i would continue to do so. But i also can very well understand if people feel they are not able to do so because they would have to sacrifice their values to do so. Voting with your feet to show where unacceptable structures exist within the OSM community is ok. The standing of an OSMF working group or any other structure within the OSM community does not derive from its formal existence but from how far it practically works for the common good of the community.
  • Create platforms and publicly cooperate to discuss and develop OSM related political ideas and strategies outside the realms and the cultural constraints of the OSMF.
  • Hold people in positions of power accountable for what they do. Openly question decisions and processes you find questionable and do not refrain from doing so because you perceive it to be socially inappropriate.
  • Help establishing moral criteria, in particular personal integrity, as the main qualifications for people to get into a position of power.

May 18, 2020
by chris

40 years since Mount St. Helens eruption

Yesterday 40 years ago in 1980 was the date of the first major volcanic eruption that was recorded by earth observation satellites. There is also imagery of the eruption itself but the more interesting images are those recorded before and after the eruption in higher resolution. Here a pair of images from Landsat 2 MSS – with color rendering based on an estimated blue channel (since the MSS instrument does not record a blue spectral channel).

For comparison here a more recent image from 2019:

April 18, 2020
by chris

Introducing the Green Marble version 2

Like almost everyone else i have been constrained in my work and life during the past weeks due to the global pandemic we are experiencing and the measures enacted to counter its spread. I used parts of this time to complete a project i have been working on on the side for the past few months and i want to introduce the results here.

That project was the update of the most successful product i have in my portfolio – the Green Marble global satellite image mosaic. Introduced in 2014 this was – and still is – the highest quality solution for an accurate visual color depiction of the whole earth surface on the market. But despite this still being the case the data basis of the image was becoming a bit dated and there are also a number of quality deficits i was looking into improving on for quite some time.

I am going to cover the various elements of improvement in more detail in the following.

Redesigned data processing for the polar regions

Arctic coverage of Green Marble 2

The so far unsurpassed quality of the Green Marble version 1 was the result in large parts of an innovative adjustment of the data processing to the different climate zones and seasonalities of the planet. Yet the fundamental process used was the same for the whole planet. This approach had its limitations in particular in the Antarctic (due to the very different climate as well as the differences in upstream data processing) and in some high latitude areas on the northern hemisphere. For the new version of the mosaic i therefore designed a new process for mosaic generation at high latitudes – both in the north and the south – that allows for lower noise levels and better differentiation of the color nuances. Source data for this is MODIS surface reflectance data like for the lower latitudes which allows seamless integration with the rest of the image.

As a byproduct this process offers (with some quality constraints on the northern hemisphere) the production of separate mosaics featuring different shading from the Terra and Aqua satellites (showing morning and afternoon lighting respectively) in addition to the standard partly shading compensated version. Here an example for these different variants from the Antarctic.

Transantarctic mountains with default partial shading compensated rendering

Transantarctic mountains with morning lighting

Transantarctic mountains with afternoon lighting

Water rendering from Sentinel-3 data

The second big change is that water depiction is now based on Sentinel-3 OLCI water relectance data. This means the oceans are now shown in approximately the same resolution as the land areas while in the version 1 mosaic only coastal waters were in high resolution and the open ocean was shown based on lower resolution data. Overall this change leads to a much more uniform ocean rendering. The use of MODIS land surface relection data for water depiction was always not quite ideal.

A few words on resolution in this context – some might wonder if the 300m vs. 250m nominal resolution difference of Sentinel-3 OLCI vs. MODIS makes a difference here – it does not. MODIS only offers 250m resolution in the red band anyway and water reflectance is primarily in the blue domain. All data processing was performed on a 250m grid and in the results i could not tell which is better. But definitely the final results due to the broader data basis offer lower noise levels and better acuity.

Great Barrier Reef

West African coast

The Bahama Banks

The Caribbean Sea

More accurate colors

On the land surfaces changes in upstream processing and improvements in the mosaicing process allowed for more accurate and consistent color rendering in particular of unvegetated and sparsely vegetated areas. This is the third big change.

Broadened data basis

And finally the fourth big improvement comes from widening the data basis. This means globally extending the range of priority use data from three to four years as well as widening the extent of the further broadened data basis in the tropics. This leads to lower noise levels in particular in high cloud incidence areas. Overall more than 60 TB of MODIS data and more than 50 TB of Sentinel-3 data were processed for the production of this image.

Northern South America

And of course the updated data basis also shows more recent changes in appearance of the earth surface.

Improved tone mapping

One of the problem in practical use of the Green Marble version 1 was the large range of reflectances across different parts of the earth surface – from dark green forest areas and dark blue ocean to bright snow and ice in the polar regions – and the difficulty of depicting that on screen. While the Green Marble version 1 was available as linear surface reflectance values and could be adjusted and optimized in rendering for specific settings the global mosaic in its default rendering was essentially overexposed in the Antarctic.

To actually be able to properly depict the high quality of the Antarctic data in the new mosaic i decided to by default use a locally adjusted tone mapping in the Antarctic region. Since this departs from the idea of a globally uniform depiction you can of course also obtain a constant tone mapping version.

Antarctic with locally adjusted tone mapping

Antarctic with globally uniform tone mapping

More samples

Here a few more samples from various parts of the world.

Southern Alaska

The Torres Strait

The Ganges delta and the eastern Himalayas

The Lambert Glacier

Europe with relief shading

An interactive map in Mercator-Projektion for further browsing can be found on

You can find the updated specifications page for the Green Marble mosaic on Existing customers with a Green Marble version 1 license are eligible for a reduced price update to the new version. If you are interested in using the Green Marble in your application contact me through the form there or via email.

February 14, 2020
by chris

Journey of an Iceberg

Two and half a year ago i showed pictures on a large iceberg calving in the Antarctic producing a more than hundred kilometer long iceberg east of the Antarctic peninsula. The iceberg has since then slowly moved away from its original location northward with the general direction of the Weddell sea ice drift and is now about to leave the area of more or less permanent drift ice and enters the open ocean. A few days ago during clear weather the following views were recorded by satellites showing this rather impressive situation.

First the larger area view based on data from Sentinel-3A shows the massive size of the iceberg dwarfing the smaller islands around the Antarctic peninsula.

Iceberg A-68 in February 2020

The second image image is a more detailed one recorded by Sentinel-2B providing a good look at the details of the iceberg itself.

Iceberg A-68 closeup

Although it is not visible on the bulk of the iceberg surface – which is covered by a thick layer of snow – as it drifts further north the iceberg is now during summer massively melting both from the bottom and the top. You can see this on a smaller sea ice area attached to the iceberg at the southeastern end shown in the following crop.

Iceberg A-68 detail

Despite this rapid melting that will increase as the iceberg floats further to the north it can take many years until the iceberg is fully dissolved. As the ice thins it will probably at some point break up into smaller pieces which can drift pretty far north – i have shown a pretty large iceberg piece north of South Georgia in 2017 at a latitude of 54 degrees south. The iceberg featured here will likely head in a similar direction.