PSA: Gratiot County 1m DEMs are in ft, not m

29 October 2021

The US 1m lidar DEM dataset (from the USGS 3DEP programme) is made up of 685 (at time of writing) projects. Each project contains multiple rasters with elevation above sea level in metres. Except one.

The Gratiot County project, named Gratiot_County_MI_QL2_LiDAR_FY15_BAA, has elevation in units of feet. This is frustratingly inconsistent, though is a good test for your QA processes!

The 25 files can be converted to metres with gdal:

 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x67y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x67y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x67y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x67y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x67y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x67y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x67y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x67y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x67y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x67y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x68y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x68y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x68y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x68y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x68y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x68y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x68y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x68y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x68y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x68y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x69y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x69y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x69y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x69y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x69y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x69y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x69y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x69y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x69y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x69y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x70y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x70y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x70y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x70y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x70y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x70y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x70y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x70y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x70y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x70y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x71y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x71y478_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x71y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x71y479_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x71y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x71y480_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x71y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x71y481_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif
 gdal_calc.py --calc="A/3.28084" -A USGS_1M_16_x71y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif --outfile ./m/USGS_1M_16_x71y482_Gratiot_County_MI_QL2_LiDAR_FY15_BAA.tif

Elevation API

GPXZ is an API for elevation data, including 1m lidar DEMs for much of the US. If you need elevation data, or help processing USGS DEMs, reach out at [email protected]!