Updates to the receding Caspian Sea

I have been adding unmaintained dirt roads that our local cycling club uses on a regular basis. These roads happen to be located in the old seabed of the north Caspian Sea in western Kazakhstan near Atyrau. I have also been adding structures, farmyards, canals etc that occupy this area. The problem is the sea left this area long ago and likely will never return. Google has the more accurate outline of the coastline but OSM has not been updated.

Is there a reason the northern coastline has not been updated? Can it be updated to mimic the Google data or can I use data from local exploration and mapping to fix it?

This is complicated by the fact that 5 countries share the Caspian and since it is defined as a lake each gets rights based on shoreline length. By losing shoreline Kazakhstan would not benefit from an accurate update if it was ever used in international arbitration.

Lacking updates the features I add have direct conflict with the shoreline. Canals that exist in open water etc. This is not a tidal area, the water is gone and has been for decades.

Please advise. I have been searching the knowledge base on how to handle this to no avail.



Firstly, a crowd sourced map, like OSM should never be used as the basis for resolving legal disputes, particularly international ones. Although not quite the same thing, there is a disclaimer page, aimed at diplomats, about why names and ownership may not match particular national claims.

If the Caspian is mapped as a lake, it will be normal user modifiable data, so any surveyor in a position to provide reliable improved surveys can update if it is wrong and they have done the surveys in person. If the original was based on professional surveys, unless the changes are so large as to completely invalidate all existing mapping in the area, the normal advice would be to overlay the OSM and professional outlines, and then visit the places where they disagree and make individual decisions, or even new measurements, to get improved data.

Almost certainly, for any solution, most of the work will need to be done by interested individuals. The most common reasons for an area not being updated is that there are not enough OSM contributors in that area. In fact, there have been changes in the last day to parts of the Caspian Sea coastline, although there is inadequate information on the source, which makes the changes even more unsuitable for any legal use. The worst case is that they have been copied from Google, which would be illegal. The lack of detail in the changeset comment indicates that they have been done by an ordinary, amateur mapper.

Incidentally, I thought that coastlines where fractal, and of infinite length, so, without some further constraints, the country with the most detailed maps would win in any decision based on coastline length!