[Imports] Import of coastlines for Greenland
chris_hormann at gmx.de
Wed Jul 29 10:58:48 UTC 2015
On Wednesday 29 July 2015, Karl Zinglersen wrote:
> On the data quality, I agree, that particularly a portion of North
> East Greenland near Daneborg is filled with problems, possibly
> because of ice conditions, shadows and more. Unhappily this is more
> or less the same regions as the GADM coastlines. Otherwise I feel,
> that the coastline is more reasonable in other areas, [...]
From looking at a few locations all around Greenland it seems while the
problems are most significant in the northeast they actually all occur
throughout all of Greenland.
> Positioning: I am afraid that many images, also from DigitalGlobe via
> Bing are badly positioned in Greenland. A couple of months ago, I
> realized a new hi-res satellite image for Nuuk instead of the older
> aerial image from Asiaq Greenland Survey. Furthermore the rest of the
> Asiaq aerials had disappeared also. The new imagery was in some
> places 30 m misplaced. I had to contact Wolfgang Walcher from
> Microsoft to bring back the Asiaq aerials (some 15 years old), I
> delivered to them some years ago, so Bing imagery was aligned with
> OSM vectors and the real world in the towns and settlements. I have
> promised Wolfgang to make a list of DigitalGlobe scenes to be
> included in Bing - to cover the less covered wilderness areas.
Note a good source for aligning images might be data from operation
icebridge (http://nsidc.org/data/icebridge/index.html). However at sea
level newer DigitalGlobe imagery is probably pretty accurate.
> Placenames across Greenland are managed by Oqaasileriffik, the
> Language Secretary, also a governmental body, whom I know very well.
> I could certainly explain and ask for openess and OSM use of their
> quite comprehensive data set.
This is probably the best place to start since they should have a
genuine interest in making their names available.
Currently the most promising and legally sound approach to find names of
features in remote areas of Greenland is to study expedition reports
and publications and cross check them with GEUS maps. Having name
lists, preferrably of course with coordinates and the permission to use
them, would be very helpful here.
In general the individual names are never subject to copyright, it is
just the collection of names that might be protected as a database.
> Chris, how do you suggest I, and hopefully others, should proceed for
> Greenland? Using new Landsat8 imagery for classification? Follow up
> on getting Microsoft to add more WorldView scenes to the map service,
> and map manually? Digitizing coastlines on the baselayer of Bing with
> only Landsat7 mosaic is probably not recommended.
Yes, using up-to-date images is generally the best approach. Priorities
of image providers like Bing and Mapbox to add new images are usually
not in remote areas so i see little chance in that outside major
settlements and prime tourist areas (like Ilulissat Fjord). The
limiting factor will always be work power since there are few mappers
who are interested in mapping these areas. Especially in light of this
it is important to not waste these ressources by letting them map from
outdated and poor quality images.
If there is a particular area you or other Greenland mappers are
interested in i can put up suitable images for mapping as i did for
but i don't have the time do this prophylactically on a larger scale.
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