[Imports] Import of coastlines for Greenland
chris_hormann at gmx.de
Tue Jul 28 19:10:12 UTC 2015
First of all the license situation of GIMP is somewhat unclear, OSM does
not qualify as academic purpose and it is not clear if the citation OSM
can provide on the contributors page on the wiki is sufficient - so you
would need explicit permission.
The current situation of the Greenland coastline in OSM en large (with
the exception of some local mapping in smaller areas) is the following:
- west coast is mostly PGS based
- east coast is mostly GADM based
- north coast is based on MODIS imagery, partly improved by Landsat in
the far north.
The GIMP land ocean mask is higher resolution than most of the current
data in OSM but of varying quality. You'd have to deal with a number
- wrong classification due to shadows and wet snow.
- positional accuracy problems due to bad alignment of Landsat images
- outdated ice coastlines due to 15 year old data basis
Examples showing this (from East Greenland as magenta mask in comparison
to up-to-date Landsat imagery and the OSM coastline (blue line)):
So to get actual improvements out of this compared to current data you'd
need to manually fix a lot of problems and would still end up with data
significantly worse than what you could produce from available imagery
by hand (or where water is ice free in summer with semi-automated
By the way if you have contacts to Greenland mapping authorities getting
data and permission to use for names of islands, mountains, fjords,
bays etc. would be most valuable. For a mapper working in essentially
unpopulated areas like northern and eastern Greenland such are
difficult to determine reliably.
More information about the Imports