[OSRS-PROJ] Orthographic Projection in Mapserver
hwehr at hs-harz.de
Fri Jan 23 01:29:02 EST 2004
Sorry for posting to this list as my problem seems to be related to
mapserver. As I get no answer on their mailing list I describe my
problem here hoping to find an answer:
I want to provide an earth in Mapserver view that looks like a globe. I
therefore use the orthographic projection but get some problems here.
As I dont' know whether it is possible to attach binary files in this
mailing list i put all example files under this url:
I made 3 examples, every example has a map file, a template output and
the resulting image.
Let me explain the examples. My data resides in a tif-file with world
information in lat/lon format. Example 1 is working as you can see in
the files containing the number 1. This example uses normal lat/lon
In the 2nd example I switched to orthographic projection with the
extends -4000000 -4000000 4000000 4000000. Projection center is lon=0
and lat=0 and does not change in these examples (I know that this has to
change every time the user performs a click. My client is able to handle
this). This output looks ok to me.
If I enlarge the extend in example 3 the output picture is cut in the
north south direction and I don't know why. I want to be able to enlarge
the extent further so that the user thinks he "moves away" from the
earth but pictures become smaller and smaller in north south direction
when I enlarge the extent further (e.G.-6200000 -6200000 6200000 6200000)
Every extent that is "higher" than the earth radius (6378000) results in
a blank image.
Can you help me here?
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