[osg-users] vpb and GTOPO30

Cedric Pinson mornifle at plopbyte.net
Mon Sep 1 03:04:52 PDT 2008


Hi Ümit Uzun
If you tell me that the problem does not appear with those map, i will 
try the big one in raw binary format.

thank you for your help


Ümit Uzun wrote:
> Hi Cedric,
>
> I use another elevation data which are grayscale images. To create a 
> good height relief whole earth database;
>
> 1 - Open up the ftp://veftp.gsfc.nasa.gov/bluemarble/ and download 
> land_shallow_topo_west.tif and land_shallow_topo_east.tif
>
> 2 - Open up the http://visibleearth.nasa.gov/view_detail.php?id=8391 
> and download srtm_ramp2.world.21600x10800.jpg (P.S. You can download 
> srtm_ramp2.world.86400x43200.bin.gz.torrent or 
> srtm_ramp2.world.5400x2700.jpg but I created my earth database with 
> using srtm_ramp2.world.21600x10800.jpg)
>
> 3 - Use "gdal_translate srtm_ramp2.world.21600x10800.jpg 
> topo_unreferenced.tif" command to convert jpg to tiff format.
>
> 4 - At this point created topo_unreferenced.tif image hasn't WGS84 
> reference meta-data. So we dig in these data with using gdal_vrt 
> files. For topo_unrefereced.tif images our vrt file is like below;
>
> ------------------------------reference.vrt----------------------------
> <VRTDataset rasterXSize="21600" rasterYSize="10800">
> <SRS>WGS84</SRS>
> <GeoTransform>180,0.016666666666666666,0,90,0,
> 0.016666666666666666</
> GeoTransform>
> <VRTRasterBand dataType="UInt16" band="1">
> <ColorInterp>Gray</ColorInterp>
> <SimpleSource>
> <SourceFilename>topo_unrefereced.tif</SourceFilename>
> <SourceBand>1</SourceBand>
> <SrcRect xOff="0" yOff="0" xSize="21600" ySize="10800"/>
> <DstRect xOff="0" yOff="0" xSize="21600" ySize="10800"/>
> </SimpleSource>
> </VRTRasterBand>
> </VRTDataset>
> ------------------------------reference.vrt----------------------------
>
> 5 - Copy and paste the reference.vrt xml data to the notepad and save 
> on your disk.
>
> 6 - Use "gdal_translate referance.vrt topo_referenced.tif" command. 
> This command create you topo_referenced.tif real whole earth elevation 
> data.
>
> 7 - osgdem --bluemarble-east -t land_shallow_topo_east.tif 
> --bluemarble-west -t land_shallow_topo_west.tif --geocentric -o 
> earth/earth.ive -so build.source
>
> 8 - osgdem -s build.source -d topo_referenced.tif -v 750.0 -l 6
>
> 9 - After build operation you should get well height relief whole 
> earth database.
>
> If any problem you get while the operation, only ask me.
>
> Best Regards.
>
> Ümit Uzun
> ------------------------------------------------------------------------
>
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>   

-- 
+33 (0) 6 63 20 03 56  Cedric Pinson mailto:mornifle at plopbyte.net http://www.plopbyte.net





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