pybob.coreg_tools

pybob.coreg_tools provides a toolset for coregistering DEMs, based on the method presented by Nuth and Kääb (2011).

pybob.coreg_tools.RMSE(indata)[source]

Return root mean square of indata.

Parameters:indata (array-like) – differences to calculate root mean square of
Returns myrmse:RMSE of indata.
pybob.coreg_tools.create_stable_mask(img, mask1, mask2)[source]

Create mask representing stable terrain, given exclusion (i.e., glacier) and inclusion (i.e., land) masks.

Parameters:
  • img (pybob.GeoImg) – GeoImg to pull extents from
  • mask1 (str) – filename for shapefile representing pixels to exclude from stable terrain (i.e., glaciers)
  • mask2 (str) – filename for shapefile representing pixels to include in stable terrain (i.e., land)
Returns stable_mask:
 

boolean array representing stable terrain
pybob.coreg_tools.dem_coregistration(masterDEM, slaveDEM, glaciermask=None, landmask=None, outdir='.', pts=False, full_ext=False, return_var=True, alg='Horn', magnlimit=2)[source]

Iteratively co-register elevation data.

Parameters:
  • masterDEM (str, pybob.GeoImg) – Path to filename or GeoImg dataset representing “master” DEM.
  • slaveDEM (str, pybob.GeoImg) – Path to filename or GeoImg dataset representing “slave” DEM.
  • glaciermask (str) – Path to shapefile representing points to exclude from co-registration consideration (i.e., glaciers).
  • landmask (str) – Path to shapefile representing points to include in co-registration consideration (i.e., stable ground/land).
  • outdir (str) – Location to save co-registration outputs.
  • pts (bool) – If True, program assumes that masterDEM represents point data (i.e., ICESat), as opposed to raster data. Slope/aspect are then calculated from slaveDEM. masterDEM should be a string representing an HDF5 file continaing ICESat data.
  • full_ext (bool) – If True, program writes full extents of input DEMs. If False, program writes input DEMs cropped to their common extent. Default is False.
  • return_var (bool) – return variables representing co-registered DEMs and offsets (default).
  • alg (str) – Algorithm for calculating Slope, Aspect. One of ‘ZevenbergenThorne’ or ‘Horn’. Default is ‘Horn’.
  • magnlimit (float) – Magnitude threshold for determining termination of co-registration algorithm, calculated as sum in quadrature of dx, dy, dz shifts. Default is 2 m.
Returns masterDEM, outslave, out_offs:
 

if return_var=True, returns master DEM, co-registered slave DEM, and x,y,z shifts removed from slave DEM.

If co-registration fails (i.e., there are too few acceptable points to perform co-registration), then returns original master and slave DEMs, with offsets set to -1.
pybob.coreg_tools.get_aspect(geoimg, alg='Horn')[source]

Wrapper function to calculate DEM aspect using gdal.DEMProcessing.

Parameters:
  • geoimg (pybob.GeoImg) – GeoImg object of DEM to calculate aspect
  • alg (str) – Algorithm for calculating Aspect. One of ‘ZevenbergenThorne’ or ‘Horn’. Default is ‘Horn’.
Returns geo_aspect:
 

new GeoImg object with aspect raster
pybob.coreg_tools.get_slope(geoimg, alg='Horn')[source]

Wrapper function to calculate DEM slope using gdal.DEMProcessing.

Parameters:
  • geoimg (pybob.GeoImg) – GeoImg object of DEM to calculate slope
  • alg (str) – Algorithm for calculating Slope. One of ‘ZevenbergenThorne’ or ‘Horn’. Default is ‘Horn’.
Returns geo_slope:
 

new GeoImg object with slope raster