Hi,

i have tried to generate a terrain (.ive) database using osgdem commandline 
options in order to buid a flat database where coordinates are in meters. After 
successfull generation i put that terrain in my osg application and really 
shocked! Before telling you what i saw as the output let me tell you my inputs.
 - i have four Dted-2 elevation file,
 - i have one GeoTiff image which is successfully mapped on dted files.
 - Dteds are starting (from 36N, 128E to 38N, 130E). So there are 4 1x1 degree 
cells [ Total size is 2x2].
 - GeoTiff image also extends from 36N, 128E to 38N, 130E. So it covers [2x2] 
elevation file without no problem.

Dted and Image Coordinate Systems are:
Geographic ( Latitude / Longitude )
Datum : WGS84
Unit : Arc degrees.

after putting dteds and image in seperate folders ( MyDted, MyImage ) i 
executed the following vpb command to generate my flat database.

- osgdem -t MyDted -d MyImage -l 8 -v 0.1 -o MyTerrain_Flat.ive

after executig above line and loading Terrain_Flat.ive on my osg application it 
was really difficult to find where is MyTerrain_Flat.ive on my view. 
When i zoom in What i saw was a 2x2 meter flat database in osg size. !!!It was 
located on x = 128 , y = 36 on my view according to ( 0,0,0) of my scene!!!
Real size of Dteds of Image was 178 km in Easting and 221 km in Northing.. i 
have checked size and everythings was ok with Dted and Image.

Now the question is 
1 - Is there a problem with vpb when creating flat database in meters? 
2- Have i missed a command line option?
3- Why is the generated terrain covers 2x2 meters although it is 178 x 221 km 
in real size?
4- Why it is located in x = 128 , y = 36 ? Those were Lower Left Lat/Lon 
coordinates of dteds and image file?
4- Isn't it possible to generate real size flat terrains in meters in x,y,z 
using vpb?

Any help is really appreciated...

... 

Thank you!

Cheers,
Atilla

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http://forum.openscenegraph.org/viewtopic.php?p=39046#39046





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