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Mapping in the Antarctic
Mapping in the Antarctic

Antarctic mapping in OpenStreetMap – a critical look

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About nine years ago i did the first import of up-to-date data for the Antarctic followed by another with more detailed data a short time later.

The intention of those was to provide a solid basis – both in terms of main physical geography features as well as for establishing basic mapping conventions – for a continent that until then had been mostly unmapped in OpenStreetMap. Essentially back then there were a few dozen nodes of research stations and individual POIs as well as some named islands and a crude overall coastline which also formed one giant glacier polygon. Mappers did not really have any context to start mapping locally (either from on-the-ground observations or imagery) what they might be interested in mapping. My hope was that providing such context in at least a rudimentary form would encourage both mapping human infrastructure (buildings, POIs), characterizing and structuring the physical geography in more detail as well as improving and updating/replacing the imported features based on newer and more accurate imagery or to take into account the movements of the ice that constantly reshapes the continent.

This initial import work was also the basis to start some attempts in displaying the Antarctic on OSM data based maps in a meaningful way. This evidently in particular refers to interpreting the implicit mapping of land ice that was established with the imports. But it also included adding support for rendering bare ground (natural=bare_rock and natural=scree) in OSM-Carto – which until then was not shown and which evidently forms the vast majority of ground not covered by ice in the Antarctic.

The state of OpenStreetMap in the Antarctic

So how have these attempts turned out in terms of community mapping in the Antarctic? The result is rather sobering. On the positive side genuine local knowledge based mapping has established itself in the Antarctic quite a bit in the form of mapping of research stations – presumably by people working there or visiting. This involves mapping of buildings, roads and paths around these as well as other human infrastructure in the surroundings of research stations. More than 1000 building and about 500 road lines of various kinds have been mapped so far. This kind of mapping has the potential to be self sustaining in the future.

Research station mapping at the Antarctic coast

Research station mapping at the Antarctic coast


Research station mapping in the Antarctic interior

Research station mapping in the Antarctic interior

However this only covers a minimal part of a vast continent. Outside the immediate vicinity of the research stations it looks much more bleak. Over the past 8-9 years almost the whole continent of the Antarctic was potentially a highly rewarding place to map physical geography, especially since 2013 when Landsat 8 was launched and began providing up-to-date high quality imagery for most of the continent. Essentially you could have taken any not fully cloud covered Landsat scene and have started mapping based on that and in most cases immediately would have produced the most accurate mapping of the area in question in existence. While this is also true for some other parts of the planet, nowhere outside the Antarctic is it that much ensured universally. Some time ago i demonstrated this on two smaller areas – one in the Antarctic interior, the other at the coast of the Antarctic peninsula, based on recent Landsat and Sentinel-2 images as well as other open data sources:

Mapping of the Belgica Mountains

Mapping of the Belgica Mountains


Mapping of Cape Calmette

Mapping of Cape Calmette

However i am nearly alone with such localized mapping of physical geography. This became even more obvious when recently someone made a well meaning but misguided change to the Antarctic coastline disrupting the routine coastline processing by moving it to the location they saw on what is unfortunately 20 year old image data. I had updated the major ice shelf edges where the ice moves most rapidly over larger sections two times since the 2013 import already and i have updated it to the state of 2021 again now (which includes taking into account the major iceberg calvings of D-28 in 2019 on the Amery Ice Shelf and of A-76 in 2021 on the Filchner–Ronne Ice Shelf). But with the exception of the mentioned ill-advised edit i was the only one who has ever worked on these ice edges during the nine years and made sure that they are not off too far. That is definitely not sustainable. And the rest of the Antarctic coastline – the majority of which is moving ice as well – has not been updated for at least nine years now (much of it for longer because the imported data was already older). This has led to inaccuracies exceeding 20km in some places.

Amery Ice Shelf edge history in OSM

Amery Ice Shelf edge history in OSM


Mismatch of OpenStreetMap ice edge data and present day situation in Lützow-Holm Bay

Mismatch of OpenStreetMap ice edge data and present day situation in Lützow-Holm Bay

At the same time the Antarctic has become kind of a playing field for imports and other mass additions of data as well as drawing of abstract labeling polygons with no connection to the observable geography. The almost complete absence of invested local mappers who could object to such edits makes it attractive for such activities.

Inconsiderate import bulldozing over existing data

Inconsiderate import bulldozing over existing data


Example for labeling polygon

Example for labeling polygon

The lack of invested mappers with interest and knowledge

The core of the problem is that OpenStreetMap in the way it functions is based on the collection of local knowledge. In the Antarctic this local knowledge is primarily in the minds of scientists and support personnel working there – not necessarily physically on the continent but on subjects related to it. And while – as pointed out – as far as this knowledge relates to human infrastructure and features significant in everyday life of people, OpenStreetMap has quite successfully recruited people with such knowledge to contribute, this does not extend beyond those narrow thematic fields.

In particular it is noticeable that OpenStreetMap has universally not managed to attract institutional scientists working on Antarctic topics to contribute to OpenStreetMap as part of their professional work. While OpenStreetMap would in principle be well suitable as a platform for scientists to exchange geographic knowledge about the continent, scientists seem to universally shy away from that. Primary reason is probably the very different work cultures and the concerns about everyone being able to edit the data in OSM and that being disruptive for any serious work (which is likely reaffirmed by many not very well informed editing activities like what i discussed before). Another reason could be that countries investing a lot of money into Antarctic research do so to support potential claims of sovereignty on the continent. A component in that is often maintaining a national cartography of the Antarctic or parts of it. And that obviously needs to be clearly attributed to the country to function as such – if mapping work would dissolve into a common international database like OSM right when being made that function would be less well served.

OpenStreetMap maintains the claim that it wants to create and maintain the best map of the world. For the Antarctic that goal has – despite some noticeable progress in the mapping of human infrastructure – become overall more distant and less achievable over the past nine years because – with very few exceptions – OpenStreetMap’s representation of the physical geography of the continent has remained static over that time period while the continent has continued to rapidly change and at the same time much better and more precise data sources have become available (in particular better and more frequent open data imagery) that increases the gap between what we have in OpenStreetMap and what would be available for mapping (and what is available to other mapping projects that compete to be the best map of the Antarctic – or parts of it).

Contributing factors

As already mentioned the Antarctic is different from other parts of the world in particular due to the absence of a larger local population from which mappers can be recruited. There are however also other circumstances that make mapping in the Antarctic particularly difficult.

Imagery is one of the main problems. Not because suitable images are not available – i already mentioned that a wide spectrum of recent open data images meanwhile exists covering most of the continent. The problem is that mappers are used to finding decent images they can map from in the main global image layers like from Bing and Maxar. But for the Antarctic that is predominantly not the case and mappers need to rethink their image choices. All global image layers use the 20 year old LIMA as base imagery for the majority of the Antarctic. And no one should map from that these days – it would be best if editors would actually prevent that.

I have made more recent images available for some quite extensive parts of the continent that mappers can use as a starting point for mapping. You can also use image layers featuring the latest data from low resolution open data satellites like the ones from GIBS. JOSM has meanwhile support for the time parameter of WMS layers – allowing you to choose the date of image recording in those. It does not work for TMS layers though and it is not very comfortable to find a day with no clouds in the area you want to map. Beyond that you are bound to manually looking for recent open data images from Sentinel-2 and Landsat and process them yourself. That might seem like a high hurdle to some – but compared to the time you also will need to invest in familiarizing yourself with the area you want to map this is actually not terribly much work.

In general OpenStreetMap’s focus on the Mercator projection also creates tons of additional practical hurdles when mapping at high latitudes like in the Antarctic. Most map styles are basically useless for feedback because you have to zoom in way too far for things to turn up. And for mappers the download area size limitations of the OSM API are annoying as well.

What i have been asking myself – and where the title of this blog post also aims at – is if the data imports back in 2013 have helped or hurt manual mapping efforts. That is not easy to answer. What we can try to do to get an idea is using the northern polar region as a point of comparison. Here different regions have seen different intensities of base mapping and imports (in Canada) in the past. It does not seem that localized mapping contribution vary very systematically between such settings. Overall manual mapping contributions are rare and usually small, independent of if there is significant pre-existing data or not. Still my observation is that because mappers of human infrastructure seem to shy away from also mapping the physical geography, providing a basic context of that can help with supporting manual mapping.

Physical geography context of station mapping

Physical geography context of station mapping

That the presence of the imported data has in some cases discouraged mappers from engaging in physical geography mapping is a possibility. Some mappers definitely find it more appealing to map on a fully clean slate instead of dealing with pre-existing data. But the data from the import is rudimentary in detail so even when mapping from Landsat or Sentinel-2 images it is clear that you can in most cases simply get rid of the pre-existing data in your area of mapping and start with nothing if you want to. So i doubt this potential influence is that significant. And there are definitely also a lot of remote mappers who like working on pre-existing geometries and simply adding detail to existing ways. This can be frequently observed in other parts of the world.

Possibly the largest influence the Antarctic imports had were the establishment of the Antarctic mapping convention of all land being implicitly ice covered unless tagged otherwise. The problem with that decision is that it was technically without alternative because plastering the whole continent with glacier polygons (or with one big glacier polygon with tens of thousands of holes) would have been unfeasible. Yet this might have been a significant negative impact factor on mapping activities because mappers receive feedback from the map with delay and mapping in this inverse fashion is not always that intuitive, especially near the coast. And among map styles interpretation of these Antarctic mapping conventions is almost fully absent beyond OSM-Carto and derivatives.

Also with the two experimental localized mapping projects i have shown above i realized that there is a significant gap in properly established and documented mapping conventions for polar regions and glacial features. A mapper working in the Antarctic who wants to properly document the reality they see on images or on the ground will often need to think about inventing new tags and mapping rules to represent this. And inventing such specific mapping rules can be very frustrating, especially if you realize that because of the exotic nature of these features the chances that data users will actually make use of them at some time are rather small.

And while the combination of all these challenges is unique globally, each of them individually can also be found elsewhere on Earth. That also means the Antarctic with its fast changing physical features might give us a glimpse into what kind of problems we can expect in other parts of the world in terms of data maintenance in OpenStreetMap also elsewhere in the future.

Conclusions

Mapping of the Antarctic – which constitutes around ten percent of the Earth land surface – represents a significant challenge for mapping in OpenStreetMap. As the data of the continent in the OSM database ages while the geography changes rapidly and increasingly more and better data becomes available that provides information on the region, this challenge will become more pressing in the future. If the OpenStreetMap community wants to maintain its goal to become the best map of the world, it needs to invest systematically in mapping of this continent and in improving the conditions for mapping it in the technical and social framework of mapping in OSM to attract more competent volunteer to contribute in that region.

There might be voices in the OSM community that suggest essentially giving up on the goal of creating the best map w.r.t. the Antarctic and focus on the naturally populated parts of the world instead. That however would create a slippery slope because the universality of a global map – aiming to map the whole planet and not just select parts of it – is a significant part of the attraction and the usefulness of OpenStreetMap for the map and the data user.

But this raises also an important further reaching question – if and to what extent the success of OpenStreetMap depends on and is tied to a functional hegemony of the project in its domain. An interesting topic for future discussion.

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