[OSM-talk] Contours, hill shading, and holes problem
sylvain letuffe
liste at letuffe.org
Tue Dec 30 20:30:01 GMT 2008
Hi,
It's probably right under my nose but I don't see it :
I followed :
http://wiki.openstreetmap.org/wiki/HikingBikingMaps
and still got trouble with :
1)
I seam to have a projection problem with the raster hill shaded image
generated by :
$ gdalwarp -of GTiff -co "TILED=YES" -srcnodata 32767 -dstnodata
32767 -t_srs "+proj=merc +ellps=sphere +R=6378137 +a=6378137
+units=m" -rcs -order 3 -tr 30 30 -multi alpes.tif alpes-mercator.tif
(+hillshading)
While contour lines are okay (I checked it with osm data I know) The hill
shaded image is somehow shifted from north to south of about 40km
See here what I mean :
http://beta.letuffe.org/?zoom=12&lat=45.51228&lon=6.21422&layers=000000000B0
Unfortunelty, when it comes to mercator projection, I'm somehow level 0, If I
am supposed to modify the line :
-t_srs "+proj=merc +ellps=sphere +R=6378137 +a=6378137" to get the good shift,
could someone point me to a rather simple mercator first step ?
2)
Holes in the srtm data seams to be considered has -30000 meters, and thus
giving me hugly artifact you can see in the upper link.
I thought the :
$ gdal_contour -snodata 32767
would get rid of them, but it seams that no
Same for the hill shading :
$ gdalwarp -srcnodata 32767 -dstnodata 32767
seams to have no effect
On the contour problem, I added
"WHERE height>0" at the mapnik layer to get a little better, but I don't think
that's the way to go
Many thanks for reading.
PS:I didn't know if talk or dev was the best place to go, so just tell me if I
should move to dev
--
Sylvain Letuffe liste at letuffe.org
qui suis-je : http://slyserv.dyndns.org
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