[osg-users] vpb and GTOPO30

Cedric Pinson mornifle at plopbyte.net
Mon Sep 1 07:05:33 PDT 2008


I tried with the small jpg and it works. I tried with the big one and 
with the vrt below it works. I will split it with a geotiff like the 
bluemarble notation A1 A2 ...

srtm_ramp2.world.86400x43200.vrt:
<VRTDataset rasterXSize="86400" rasterYSize="43200">
  <VRTRasterBand dataType="Int16" band="1" subClass="VRTRawRasterBand">
    <ColorInterp>Gray</ColorInterp>
    <ByteOrder>MSB</ByteOrder>
    <ImageOffset>0</ImageOffset>
    <PixelOffset>2</PixelOffset>
    <LineOffset>172800</LineOffset>
    <SourceFilename 
relativeToVRT="1">srtm_ramp2.world.86400x43200.bin</SourceFilename>
  </VRTRasterBand>
</VRTDataset>

Thank you for the tips
Cedric

Ümit Uzun wrote:
> And another tick, if you will use different srtm elevation image while 
> creating database, you should chage the vrt xml data for new image 
> resolution values.
>
> 2008/9/1 Ümit Uzun <umituzun84 at gmail.com <mailto:umituzun84 at gmail.com>>
>
>     Hi Cedric,
>
>     Yes, you can make your terrain with this method. There would not
>     be any problem because I create
>     http://img222.imageshack.us/my.php?image=tasimearthjb4.png
>     database with using this way. But I suggest you to create smaller
>     one and if there is not problem you can create bigger one with
>     comfort.
>
>     May it be easy. Best Regards.
>
>     Ümit Uzun
>
>     2008/9/1 Cedric Pinson <mornifle at plopbyte.net
>     <mailto:mornifle at plopbyte.net>>
>
>         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 <mailto:mornifle at plopbyte.net>
>         http://www.plopbyte.net
>
>
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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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