Laser altimetry data from the NASA IceSAT spacecraft is used to compute x, y, and z offsets for ArcticDEM strip files. The values of these offsets are contained within the DEM metadata, but are not applied. How can I apply these altimetry-derived offsets myself? Solutions using Python / GDAL are ideal but I am really just looking for the logic.

An example metadata file and translation vector:

DEM Filename: WV02_20160702_10300100590AAE00_1030010058954200_seg1_2m_dem.tif
Registration Dataset 1 Name: GLA14_rel634
GCP Month Range (+/- months)=1
# GCPs=563
Mean Vertical Residual (m)=0.004
Median Vertical Residual (m)=-0.003
Translation Vector (dz,dx,dy)(m)= 1.213, 0.366, 0.097 
Vertical Deviation Percentiles(m):
50th percentile=0.340 
55th percentile=0.372 
60th percentile=0.417 
65th percentile=0.462 
70th percentile=0.519 
75th percentile=0.580 
80th percentile=0.640 
85th percentile=0.741 
90th percentile=0.849 
95th percentile=1.043 
100th percentile=5.235 

There is a Python code for this on the ArcticDEM page: "Strip DEM files are provided at 2-meter spatial resolution in 32-bit GeoTIFF format. Elevation units are meters and are referenced to the WGS84 ellipsoid. Strip DEM files include metadata text files describing the xyz offsets to filtered IceSAT altimetry data, although these translations have not been applied to the DEM files. A Python script for applying these translations on the downloaded strip DEM files is hosted on the Polar Geospatial Center GitHub page, along with other useful geospatial data processing utilities."

Having said that, I'm not sure exacytly how the translation is applied (i.e. whether the xyz offsets should be added or subtracted.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.