Hi David,

The OSG doesn't have any particular units, it just works with the data
you have.  If your data ranges from 0 to 10 then its just render that,
its up to your app how your interepret it.

Robert.

On 8/1/06, David Colbert <[EMAIL PROTECTED]> wrote:
Antoine, thanks for the osgpick suggestion. It confirmed my problems...

It appears to be a units problem that I am having. OSG app units are meters.
My terrain units are all  degrees, so a 10 degree by 10 degree terrain shows
up in OSG as a 10 meter by 10 meter terrain. Does anyone know how to output
the terrain in  meters?  I tried  gdalwarping the file from degrees into
meters by running  it through a gdalwarp -t_srs 'EPSG:4326 +units=meters'
in.tif out.tif, which did change the "degree" unit to "metre" unit as
returned by gdalinfo.

However, when I run the new file through osgdem, I still get a 10 meter by
10 meter terrain. Does osgdem recognize these units changes? I went back and
made a bunch of test terrains with DEM, SRTM, geotiff, DTEDs, and they all
ended up as many meters wide as they were degrees wide, no matter how I
warped them or changed their metadata.

Any ideas?

Thanks in advance,
David




On 8/1/06, Antoine Hue <[EMAIL PROTECTED]> wrote:
> David Colbert wrote:
> > Hello All,
> >
> > <snip>
> >
> > My terrain looks okay in osgviewer, but when I load it into my app,
> > it's tiny. Like less than 10 meters across tiny. Obviously, my scale
> > is messed up, but I cannot find out what more I need to do. I set the
> > corner anchors using -a_ullr; I tagged 3 points with gcp to provide
> > additional geocorrelation information; and I set the coordinate system
> > to match the coordinate system in the README pdf for the blue marble
> > imagery.
> >
> > Did I do something wrong? Is this a bug? Any help would be much
> > appreciated. The example with pegout says that -xx -yy is unecessary
> > if you have all the geo metadata, which I believe that I do.
> >
> Hello David,
>
> You are right, -xx and -yy are not needed in your case.
> You may check the actual coordinates using osgpick instead of osgviewer
> (same command usage).
>
> Antoine
>


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