How to Extract the River Reach Geometry for HMA2_RSRD using GDAL

This article provides a guide on how to extract and export river reach geometry data contained within the High Mountain Asia Daily Reach-Scale River Discharge using Data Assimilation, 2004–2019, Version 1 NetCDF file -- HMA2_RSRD_2004-2019_daily_discharge_V01.0.nc.

Prerequisites

To extract the river geometry, you must have the Geospatial Data Abstraction Library (GDAL) installed on your system.

GDAL Website: http://gdal.org/

Extracting the Reach Geometry

Within the NetCDF file, the river geometry information for all river reaches is stored in the variable named geometry_container.

To extract the geometry_container data and export it as a GeoPackage (.gpkg) file, execute the following command in your terminal:

ogr2ogr -f GPKG <output_filename>.gpkg HMA2_RSRD_2004-2019_daily_discharge_V01.0.nc geometry_container

Note: Replace <output_filename> with the desired name for your output file.

The river geometry may also be exported to various other supported formats by simply changing the output format flag (-f) and ensuring the output file extension matches.

For example, use the following command to export the geometry as a shapefile:

ogr2ogr -f "ESRI Shapefile" <output_name>.shp HMA2_RSRD_2004-2019_daily_discharge_V01.0.nc geometry_container

Note: If the .shp extension is not included in this command, a new directory named <output_name> will be created. This newly created directory will contain the .shp file as well as its sidecar files (e.g., .prj, .dbf, .shx).
- If .shp is included in the command like the example above, the .shp and its sidecar files will each be placed in your current working directory.

For more information on the ogr2ogr command, including other supported formats and advanced options, refer to the official GDAL documentation: https://gdal.org/en/stable/programs/ogr2ogr.html