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flyfisher

Importing STRM elevation data with Sceenry Editor

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Happy New Year to all,I have tried to import some elevation SRTM data using the Fly II Scenery Editor with surprising results,see screenshots.Is it because I used the wrong settings for the Samples, (Width and height) boxes or the wrong Subdivide Tolerance or is it because of the holes in the SRTM data?I set the maximum density to 8X8.I used about a quarter of a 3 Arc- sec file converted by 3DEMBIN2RAS Can anyone help me improve on this?Thanks,:-hmmm

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Hi Flyfisher,the geographical coordinates are exact?-Samples (Width and height): dimension of the image RAS (1201x1201).-Subdivide Tolerance: 50 foot.Dan

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Dan,Thanks. Yes the coordinates were taken directly from the 3DEM image I had opened.Could there be any conflict with the data in the FlyII database?Sample size 1201X1201 and Subdivide Tolerance 50.

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Hi,It looks to me as though the textures are wrong.Is this an area that you have TerraScene'd or does it just have default textures?Which tile is it?Colin

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Colin,I wondered whether it is due to holes in the SRTM data.The tile is 124,100 and I used the default textures.I tried a second time after using SRTMFill and it was even worse and kept crashing to desktop.

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Hi,It *shouldn't* be the holes, if there are any.Holes would normally just create false lakes at 0 elevation and shouldn't crash the program.If you can mail me the 4 g**.trn files from the D124100 folder that the scenery editor created I can take a look for you.I still think that it's a texture problem.Colin

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Hi Flyfisher,If you merged several SRTM blocks, with 3DEM :- did you export BIN file from 3DEM with "signed integer format" ?- The lat/lon for DEM import are always round values (as 48.0N 1.0W TO 51.0, 0.0W), beware of the right way when you are working West (higher values go "Lower left" input.Then the nbr of points you have to fill in FlyEditor are related to the number of SRTM merge in both dimensions (DemBin2Ras give you the width):width = (1201 * nbr HorizontalSRTMBlocks) - (nbr HorizontalSRTMBlocks - 1)height = (1201 * nbr VerticalSRTMBlocks) - (nbr VerticalSRTMBlocks - 1)- roland -* ROTW member *

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Hi Ian,I got my answer with the first file I opened :-)It IS the textures, or rather, the lack of them that is causing the problems.This is because the underlying type of a lot of the ground tiles is wrong.Basically, Fly works like this:TRI built in a rather rough map of the world cut up into 256 x 256 globe tiles.These globe tiles are then split into a 64 x 64 grid of ground tiles.Each ground was given a value based on some kind of land cover data.These values are the ones you see in TerraScene like water/ocean, Euro mixed farm, USA city etc.All these values are placed in 1 huge file called tiletype.img which is in Globe.pod.This file is 256 x 256 x 64 x 64 bytes long, i.e. 268435456 bytes or 256mb!A lot of the ground tiles that you have now given elevation values to are classed as water, hence the strange looking scenery.Obviously, the geography of NZ is way out in Fly

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Colin,Thanks very much for your help.I had noticed that there are a lot of tiles in NZ that should be land and yet are water and have corrected a lot of them with Ground Tile Transformer already.I didn't realise the island suffered from the same problem but I guess it does explain why when I flew through one of the vertical elevations I went through a vertical wall of water!!!I shall continue with my efforts at creating some worthwhile NZ scenery. At least with no FlyIII in the offing we are able to add to FlyII without feeling our efforts will be superceeded in the near future.:-wave

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