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Holger

What filetype for read_dem.exe?

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Hi,I just wanted to get into converting USGS elavation data to flight simulator, but it looks like there are no tutorials for the current situation available. :(The link for DEM data mentioned in the FS2004 Terrain SDK (http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_demfig/index1m.html) isn't available anymore. It looks like that all USGS elevation data is obtainable from the new Seamless Server only.But that's where the problem starts. The seamless server offers so many elevation data formats that I don't even know what to download. What I get is a zip file with many files not readable by Microdem or Read_Dem.exe.Does anyone know what data format to download from the Seamless server to get it usuable for the FS2004 Terrain SDK?ThanksSascha

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Hi,the BIL format from the seamless server is usable directly for the terrain SDK resampler. The simple *.bil data matrix is 16-bit least significant byte first (LSB, also called Intel). Metadata for the source section of the inf fileLat =Lon =NumOfCellsPerLine =NumOfLines =CellXDimensionDeg =CellYDimensionDeg =are all in the files *.blw and *.hdr.The srtm data needs corrections for the precise positioning of the upper left point, the 3arc sec from the formulas ULXMAP : = ULXMAP + sign(lon)*0.00041667 (west minus, east plus) ULYMAP : = ULYMAP + sign( lat

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Hi Sascha,here's a thread that explains the necessary steps: http://forums.avsim.net/dcboard.php?az=sho...ing_type=searchYou can use the raw data as is but make sure that you're familiar with the mesh LOD grid system: http://www.fs-traveler.com/tips-d.shtmlIn addition, you can either use MircoDEM - http://www.usna.edu/Users/oceano/pguth/website/microdem.htm - to subset the raw data or use Slartibartfast - http://www.jimkeir.co.uk/FlightSim/AutoGen/index.html - to fill in the holes of SRTM data, should you prefer/need to use SRTM. Finally, never forget to check your compiled bgl files with either TMFViewer (comes with the Terrain SDK) or LWMViewer ( http://www.jimkeir.co.uk/FlightSim/LWMViewer.html ); it's easy to miss mesh problems in the sim but they are usually very easy to spot in either viewing tool.Cheers, HolgerP.S.: Hi Vlada - we posted at the same time ;-)

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