On Mon, 17 Jan 2011 20:24:40 +0200, clipka <ano### [at] anonymousorg> wrote:

> Am 17.01.2011 15:59, schrieb Nekar Xenos:
>> It would be wonderful if we could use .dem and .hgt formats for
>> heightfields as these are the native file formats for terrain data.
>
> Do you have a source for file format documentation? A (not necessarily  
> complete) list of software that generates files in this format might be  
> interesting, too.

Maybe this will help:

"Height files have the extension .HGT and are signed two byte integers.
The
bytes are in Motorola "big-endian" order with the most significant byte
first,
directly readable by systems such as Sun SPARC, Silicon Graphics and
Macintosh.
DEC Alpha and most PCs use Intel ("little-endian") order so some
byte-swapping
may be necessary. Heights are in meters referenced to the WGS84 geoid.
Data
voids are assigned the value -32768."

-From http://freegis.org/pipermail/freegis-list/2004-December/002013.html

and

"GDAL includes support for reading USGS SDTS formatted DEMs. USGS DEMs are  
always returned with a data type of signed sixteen bit integer, or 32bit  
float. Projection and georeferencing information is also returned.

SDTS datasets consist of a number of files. Each DEM should have one file  
with a name like XXXCATD.DDF. This should be selected to open the dataset.

The elevation units of DEMs may be feet or meters. The GetType() method on  
a band will attempt to return if the units are Feet ("ft") or Meters  
("m")."

-from http://www.gdal.org/frmt_various.html

Maybe you can also find more info here: http://grass.osgeo.org/

-- 
-Nekar Xenos-

"The spoon is not real"

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