nasadem

Scripts to download and process the NASADEM SRTM products

• Note: TanDEM-X global mosaic processing scripts moved here: https://github.com/dshean/tandemx *

NASADEM SRTM products (provisional)

Information about the NASADEM project: https://earthdata.nasa.gov/esds/competitive-programs/measures/nasadem

Offical data product release: https://lpdaac.usgs.gov/news/release-nasadem-data-products/

Provisional tiles (used for this repo) downloaded from: https://e4ftl01.cr.usgs.gov/provisional/MEaSUREs/NASADEM/

Requirements

Some scripts rely on utilities in these packages:

• pygeotools
• gdal_tools
• GDAL/OGR
• NASA Ames Stereo Pipeline (ASP)
• NumPy

Tools

• srtm_proc.sh - wrapper to process all downloaded tiles and create mosaics
• srtm_tilelist.py - script to fetch tiles for given lat/lon bounds and product type
• srtm_hdr.sh - create an ENVI header for the raw tiles
• srtm_post.sh - post-process mosaics with error filter, vertical datum shift, reprojection, shaded relief map generation
• srtm_errmask.py - apply max error threshold filter to hgt tiles

Note: these were written for one-time processing of regional mosaics for existing projects. They call several other scripts (listed in Requirements section), with limited error checks. I've tried to clean up and generalize, but don't currently have time for further refinement or usage improvement. Please treat them as a reference, and feel free to fork and modify hardcoded values for your own needs.

High-mountain Asia mosaics

Mosaic parameters:

• Resolution: 30 m
• Extent: (25N, 65E, 47N, 106E)
• Projection: WGS84 (EPSG:4326) and Custom HMA Albers Equal Area

Available Products:

The following are available for HMA and CONUS.

All products have external overviews (*.ovr) derived using average resampling. These enable fast visualization of the otherwise unweildy full-res tif files.

Elevation

Geographic coordinates

• hma_nasadem_hgt.tif - srtmOnly elevation, height above WGS84 Ellipsoid, 32-bit float
• hma_nasadem_hgt_lt5m_err.tif - srtmOnly elevation, masked to preserve pixels with <5 m error, 32-bit float

Equal-area projection:

• hma_nasadem_hgt_aea.tif - same as above, reprojected with Albers Equal Area
• hma_nasadem_hgt_lt5m_err_aea.tif - same as above, masked for error <5 m
• hma_nasadem_hgt_aea_hs_az315.tif - shaded relief map, illumination azimuth 315°, elevation 45°
• hma_nasadem_hgt_lt5m_err_aea_hs_az315.tif - shaded relief map

Error

• hma_nasadem_err.tif - elevation error in mm, 16-bit Int

Color ramp from 0 to 10 m

Image

• hma_nasadem_img.tif - mosaiced radar backscatter images, 8-bit

Note that some tiles were missing when this figure was generated. These will be available in the final product release.