I recommend reprojecting them first. You can use gdalwarp, or a tool like Global Mapper.
You may also want to investigate osgEarth as an alternative approach to doing terrain with OSG. Glenn Waldron / Pelican Mapping / @glennwaldron On Thu, May 5, 2011 at 1:08 PM, Atilla Selem <[email protected]> wrote: > Hi Glenn, > Thanks for the tip.. but i really need to know, > > Where should i do reprojection? In my dted-2 files and/or in my > GeoTiff.file (since their projections are both Geographic - Lat/Lon) before > executing osgdem? > Or should i do re-scaling or whatever after i load terrain in osg > application? > And What tool or command option should i use to reproject to UTM? > > thanks in advance.. > > Atilla. > > > > Glenn Waldron wrote: > > 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( > 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 < ()> 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 ( > http://forum.openscenegraph.org/viewtopic.php?p=39045#39045) > > > > > > > > > > > > > > > > > > _______________________________________________ > > > osg-users mailing list > > > () > > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org( > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org) > > > > > > > > > ------------------ > > Post generated by Mail2Forum > > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=39053#39053 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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