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Guest Dasher7

FSdem render time? GTOPO-30 reproject?

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Hi Emerson and all you others.After setting up my GTOPO30 tile and everything looks good, I have some other question:1)What do you estimate the rendering time for the entire DEM in LOD7on my rather quick P4 computer? Are we talking two hours or two weeks?Mine has been rendering for quite a while and I'm still only getting sealevel values (of which there are many in the particular DEM).2)Is there a way to repoject the file? I tried simply halving the geographical extents of the file with Globalmapper, then I inserted in FSdem half the number of rows and columns as the original file. (6000/4800 to 3000/2400).FSDem then gives me "wrong size" error.Did I make a mistake when reprojecting or is the nature of the DEM format not so simple?Hope to hear from you all,Dasher7

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>1)>What do you estimate the rendering time for the entire DEM in>LOD7>on my rather quick P4 computer? Are we talking two hours or>two weeks?>Mine has been rendering for quite a while and I'm still only>getting sealevel values (of which there are many in the>particular DEM).Which rendering time you mean? Frame rate in Flight Simulator? Load time? Whatever: it should be high frame rate and "fast" loading (less than a minute :) ). If not, there's something wrong with your mesh, or your computer is under the minimum specs (seems not be the case...).The rendering time (in FSDEM) mainly depends on how much RAM memory is available, because the whole mesh is loaded into RAM memory at once. There's no memory/tile swapping mechanism embedded in FSDEM. A single GTOPO 30 tile is not a problem for most systems. In my "weakest" computer, a P4 2.8Ghz, 1Gb RAM, GeForce2 GTS 64Mb, the rendering time is pretty good at 1x zoom and lower. If you have less than 256MB of RAM, or is running Windows 98, you might have performance problems with FSDEM. Check the minimum hardware requirements in the README.TXT file.>>2)>Is there a way to repoject the file? >I tried simply halving the geographical extents of the file>with Globalmapper, then I inserted in FSdem half the number of>rows and columns as the original file. (6000/4800 to>3000/2400).>FSDem then gives me "wrong size" error.>Did I make a mistake when reprojecting or is the nature of the>DEM format not so simple?Probably a mistake. Check if the resulting file format is correct.Regarding the error message from FSDEM:FSDEM can read 16-bit signed integer binary raster files only, i.e., each elevation value must be stored as a 16-bit word (=2 bytes), in binary format (not ASCII format, aka "text"). By the way, this is the same format required by Microsoft Resample, which is the tool that actually creates the BGL file. Your input DEM file must have exactly 14,400,000 bytes (= 3000 x 2400 x 2). If not, FSDEM will refuse to load the DEM, because the file size mismatch for the given dimensions. So check if the file size is correct. And check the file format as well.Emerson

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Hi!Thanks once again, Emerson.The reason I asked about rendering time (from when I press create BGL until the BGL is compiled) is that my comp is on day 4 now! I must have messed something up AGAIN then ;(Since I'm not online at home, I'll have to get back to you on my reprojection errors. I'm still new at mesh-creating, but getting there.I'll get back to you when I worked it out!Thanks,Dasher7

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>The reason I asked about rendering time (from when I press>create BGL until the BGL is compiled) is that my comp is on>day 4 now! I must have messed something up AGAIN then ;(OK, now I understand what you meant: Resample processing time as "rendering time".First thing to do: stop Resample! It

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Hi againTada! I got it all working now that I changed the elevation values to 0. I made both a LOD5 and LOD6 file, the LOD7 bgl was not succesful. As it turns out, the LOD5 bgl was EXACTLY like the default FS mesh, so at least for Geenland the default mesh is certainly GTOPO LOD5.As a function of using corrected coasts and lakes the LOD6 file is not only more detailed but, I believe, more precise because it adapts better to those coasts and lakes. Thanks for all your support, Emerson, looking forward to seeing FSDem v.2.Cheers,Dasher7

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