Last active
August 29, 2023 05:41
-
-
Save phargogh/f673a1c1c62d930cbb30cc62f5d7a92d to your computer and use it in GitHub Desktop.
Example of pygeoprocessing-based D8 routing, including watershed delineation.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import os | |
| import shutil | |
| import numpy | |
| import pygeoprocessing | |
| import pygeoprocessing.routing | |
| from osgeo import gdal | |
| def doit(dem_path, flow_dir_weights, watershed_source_vector, workspace): | |
| if not os.path.exists(workspace): | |
| os.makedirs(workspace) | |
| aligned_dem_path = os.path.join(workspace, 'aligned_dem.tif') | |
| aligned_weights_path = os.path.join(workspace, 'aligned_weights.tif') | |
| # Align the DEM and weights raster | |
| pygeoprocessing.align_and_resize_raster_stack( | |
| [dem_path, flow_dir_weights], | |
| [aligned_dem_path, aligned_weights_path], | |
| ['bilinear', 'bilinear'], | |
| pygeoprocessing.get_raster_info(dem_path)['pixel_size'], | |
| bounding_box_mode='intersection') | |
| # Flow direction | |
| flow_direction_path = os.path.join(workspace, 'flow_dir.tif') | |
| pygeoprocessing.routing.flow_dir_d8( | |
| (aligned_dem_path, 1), flow_direction_path) | |
| # Flow accumulation with weights. | |
| flow_accumulation_path = os.path.join(workspace, 'flow_accumulation.tif') | |
| pygeoprocessing.routing.flow_accumulation_d8( | |
| (flow_direction_path, 1), flow_accumulation_path, | |
| (aligned_weights_path, 1)) | |
| # Create streams layer | |
| flow_accumulation_nodata = pygeoprocessing.get_raster_info( | |
| flow_accumulation_path)['nodata'][0] | |
| streams_nodata = 255 | |
| flow_threshold = 1000 # This is the TFA | |
| def _filter_streams(flow_accumulation): | |
| out_array = numpy.full(flow_accumulation.shape, streams_nodata, | |
| dtype=numpy.uint8) | |
| valid_pixels = (flow_accumulation != flow_accumulation_nodata) | |
| out_array[valid_pixels & (flow_accumulation >= flow_threshold)] = 1 | |
| out_array[valid_pixels & (flow_accumulation < flow_threshold)] = 0 | |
| return out_array | |
| streams_raster_path = os.path.join(workspace, 'streams.tif') | |
| pygeoprocessing.raster_calculator( | |
| [(flow_accumulation_path, 1)], | |
| _filter_streams, | |
| streams_raster_path, | |
| gdal.GDT_Byte, | |
| streams_nodata) | |
| # Delineate watersheds | |
| target_watersheds_path = os.path.join(workspace, 'watersheds.gpkg') | |
| pygeoprocessing.routing.delineate_watersheds_d8( | |
| (flow_direction_path, 1), | |
| watershed_source_vector, | |
| target_watersheds_path) | |
| if __name__ == '__main__': | |
| # This function call assumes that everything is in the current working directory: | |
| # ./ | |
| # ./my_dem.tif | |
| # ./weights.tif | |
| # ./points.gpkg | |
| # ./workspace/ | |
| doit('my_dem.tif', 'weights.tif', 'points.gpkg', 'workspace') | |
| # You could also use absolute paths for any of these. | |
| # Relative and absolute paths can also be mixed and matched. | |
| # For example: | |
| doit( | |
| '/Users/my_username/Documents/my_dem.tif', | |
| '/mnt/data/my_project/weights.tif', | |
| '/home/points.gpkg', | |
| './workspace' | |
| ) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment