i am working on a project which is not commercial and i need some digital elevation data for visualization. in net i have found a link and i have downloaded .asc data from following link..
with arcmap in toolbox, Conversion Tools > To Raster > ASCII to Raster , with floating options i can convert it to what i want. but when i export it as tiff and taking info with gdalinfo i am getting no coordinate system information and three band (RGB)…
in normal dted2 file with gdalinfo i am getting this result with other coordinate info:
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]]
Pixel Size = (0.000277777777778,-0.000277777777778)
Image Structure Metadata:
INTERLEAVE=BAND
Band 1 Block=3601x1 Type=Int16, ColorInterp=Gray
NoData Value=-32767
Unit Type: m
Can you help me how can i convert srtm asc data to dem or dted as below with arcmap or gdal? and is there any batch conversion for this?
Best Answer
I do it this way:
I download srtm data from : http://srtm.csi.cgiar.org/SELECTION/listImages.asp Also, I just checked, use ftp to download, its a lot faster than http.
Then load it in Global Mapper, re-project in to desired coordinate system and export as 32 bit floating point elevation data. (yes its that simple, 2 min job at max). I tried in ArcMap and did some google search, seems like ArcMap doesnt like DEMs very much.
If you dont have GlobalMapper, go for GRASS. There you have to read a few things to make what you want, but it will work I believe.
Cheers N