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Hamish wrote:
<blockquote cite="mid:961097.25964.qm@web45812.mail.sp1.yahoo.com"
type="cite">
<pre wrap="">Richard:
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<pre wrap="">I hope this is the last maddening issue; working with:
g.region n=33S s=34S w=150 e=151 nsres=00:00:05 ewres=00:00:05
r.in.wms -c
mapserv=<a class="moz-txt-link-rfc2396E" href="http://www.ga.gov.au/wms/getmap?dataset=national&">"http://www.ga.gov.au/wms/getmap?dataset=national&"</a>
-g layers=dem_9sec output=dem_9sec format=png srs=EPSG:3112
(The small region keeps the the tile size down)
I get the 9-second DEM. It looks and displays okay, but the
elevation data is wild.
r.what -f input=dem_9sec@PERMANENT
east_north=150.8177882,-33.785157971
produces:
150.8177882|-33.785157971||31407|
Since I can reasonably assume that the elevation isn't
31,407 metres, nor that the elevation in the mountains
is lower than near the ocean, something's awry with the
elevation...
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<pre wrap=""><!---->
I am afraid you are not looking at the elevation, but rather the color palette entry of the PNG file. ie this is a "visual only" exercise.
WMS servers can dish up real data, but I suspect that to do that they need to support geotiff format, and the GA server only provides tiff/png/jpeg/wbmp pretty imagery. I'm not sure about that though, maybe someone reading knows better about this.
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Damn, I think you're right. The TIFF, which I thought included
elevation data, seems to suffer a similar problem. Still, all is not
lost, because I can get the elevation data from a vector map of the
relevant area and create a real DEM ... <br>
<br>
Richard<br>
<blockquote cite="mid:961097.25964.qm@web45812.mail.sp1.yahoo.com"
type="cite">
<pre wrap="">
if you look in the capabilities XML file you will see that geotiff is conspicuously missing from the available image formats:
<a class="moz-txt-link-freetext" href="http://www.ga.gov.au/wms/getmap?dataset=national&request=capabilities">http://www.ga.gov.au/wms/getmap?dataset=national&request=capabilities</a>
If you find no joy, I'd suggest contacting Geosci Aust and asking about it; and also on the Aust-NZ OSGeo mailing list as well. There are some talented people at both places who may be able and keen to help.
Hamish
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