How to download SRTM files
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For example you can use USGS Earth explorer website https://earthexplorer.usgs.gov
Create new account - Register profile
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How to find and download files in EarthExplorer
In EarthExplorer Zoom map on the area of interest for DEM files download
Under first tab – Search Criteria – select Polygon and Use Map
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Under DataSets Tab select Digital Elevation – SRTM – SRTM 1 Arc-Second Global
Click Results to get resulting list
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In the Results tab select file you want to download
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For download select bil type of file
There is option for bulk download of many files, but it downloads not just bil but other formats
Definition of files naming and format:
https://lta.cr.usgs.gov/DD/srtm.html#entity_idAnchor
Entity ID
Field Definition: This field describes the naming convention of each tile.
Format:
SRTM3N35E089V1
SRTM = Dataset designator
1 or 3 (1 = 1 arc-second coverage, 3 = 3 arc-second global coverage)
N or S (N = North, S = South hemisphere)
Next two characters indicate lower left corner Latitude
E or W (E = East, W = West hemisphere)
Next three characters indicate lower left corner Longitude
V1, 2, or 3 (1 = SRTM Non-Void Filled, 2 = SRTM Void Filled, 3 = 1 Arc-Second Global)
Where to find and how to download ASTER GeoTIFF files
ASTER files are provided in GeoTiff format and only available for 1 Arc-Sec resolution (30 m). ASTER stands for Advanced Spaceborne Thermal Emission and Reflection Radiometer done by the Ministry of Economy, Trade, and Industry (METI) of Japan and the United States National Aeronautics and Space Administration (NASA).
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Link to ASTER GDEM Web Site
Format of file name:
ASTGTMV003_XXXXXXX_dem.tif
Field Definition: This field describes the naming convention of each tile.
Format:
ASTGTMV003_N45E015_dem.tif
ASTGTM = Dataset designator
V003 = version of source data
N or S (N = North, S = South hemisphere)
Next two characters indicate lower left corner Latitude
E or W (E = East, W = West hemisphere)
Next three characters indicate lower left corner Longitude
dem = designation for DEM data
Explanation of the format:
Geospatial World, “GeoTIFF – A standard image file format for GIS applications,” Online:
https://www.geospatialworld.net/article/geotiff-a-standard-image-file-format-for-gis-applications/
NASA Earth Data, “GeoTIFF File Format,” 'Online:
https://cdn.earthdata.nasa.gov/conduit/upload/12430/ESDS-RFC-040v1.1.pdf
Open Geospatial Consortium, “OGC GeoTIFF standard,” 2019, Online:
http://docs.opengeospatial.org/is/19-008r4/19-008r4.html
Adobe, “TIFF,” Revision 6, 1992. Online:
https://www.adobe.io/content/dam/udp/en/open/standards/tiff/TIFF6.pdf
Aware Systems, «TIFF File Format,» Online:
https://www.awaresystems.be/imaging/tiff.html
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