Atilla, osgdem is creating your model in what's called a "plate carre" projection -- in which degrees are simply reinterpreted as meters. That is why your 2x2 degree cell is appearing as 2x2 meters.
You need to reproject into a proper projected spatial reference system (like UTM) to get the correct extents. Check the bottom of this page for tips: http://www.openscenegraph.org/projects/osg/wiki/Support/UserGuides/osgdem Glenn Waldron / Pelican Mapping / @glennwaldron On Thu, May 5, 2011 at 12:25 PM, Atilla Selem <[email protected]>wrote: > 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 > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=39045#39045 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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