[OSM-talk] SRTM relief
Artem Pavlenko
artem.mapnik at googlemail.com
Wed Jan 2 21:55:44 GMT 2008
Hello lists,
Sometime last year I was inspired by http://www.srtm.com and I even
contacted developer to see if we can use SRTM derived relief maps in
OSM.
I don't remember all details but reply was somewhat ambiguous: yes
OSM can use pre-rendered tiles from the site above, source code (in
Java ) is a bit messy, cause my crazy mate coded something ...
Anyway, while srtm.com tiles look good on its own, colour scheme is
not suitable for overlaying with OSM data IMHO. So I thought it would
be fairly straight forward to implement something from scratch.
Here is what I'm thinking about - a c++ command line app, which given
bounding box in geographic coordinate system (WGS84) would read
compressed raw SRTM files and output 'nice' looking maps (tiles) in
specified projection (I only care about Mercator and OS NatGrid but
others will work as well).
Here is more detailed feature list:
1. highly configurable
2. all steps needed to produce final relief map included (relief,
blending , warping etc)
3. read raw compressed SRTM directly
4. easy to add new algorithms
5. using GIL from Adobe for accessing pixels and implementing algos.
6. mapnik and OSM ready
7. perhaps it can be used for outputting contours as well (?)
I've coded a prototype based on excellent posting on http://
perrygeo.net/wordpress/?p=7 and I'm looking for a good color scheme
that would work for the whole planet, any pointers?
Here is some test outputs:
http://artem.dev.openstreetmap.org/files/relief_osgb.png
http://artem.dev.openstreetmap.org/files/srtm_relief.png
(red pixels are voids and I'm yet to fill them, did someone mentioned
some good algorithms a few months ago?)
The kind of reliefs I think might work well for OSM are gmap terrain
or perhaps Yahoo style.
Any ideas or comments? Cartographers?
Thanks in advance
Artem
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