[mapserver-users] How to get maximum and minimum height from DTED file

[Frank Warmerdam]

Admin wrote:
> Hi, I have to get maximum and minimum height from DTED file. MapServer
> render it as 8bit gray image. Thats ok, but i also need some information
> about height of this map. When i open my dted file in OpenEV and i go to the
> layer properties (Raster Source tab) i see values for Scale Min: and Scale
> Max:, that means that in dted are stored height information, but when i use
> gdalinfo i don't see this information. I wrote simple additional cgi
> program, which have to return me hight information (it will be using
> external application such as gdalinfo, ogrinfo or something else), but i
> don't know which console program from FWTools can i use to get this max and
> min height. Have you got any idea how do this? 

"Admin Mail Deamon",

OpenEV does not get the min/max for scaling from the image header, it samples
the image and does various computations with the resulting histogram.

To get the exact min/max with gdalinfo pass the -mm switch to compute the
min and max by scanning the whole image.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org