I have a vector file of river networks in QGIS. Some of the rivers are split up it multiple rows. What I'd like to do is to aggregate the rivers based on the attribute in one column (
S_NAME) and afterwards calculate the length of each aggregated river.
I know there must be some PostGIS commands to do that. I'd be fine with any pointer to anything that relates to it. The pseudo-code I have in my head would look something like this:
output = layer -> groupyby(S_NAME) -> st_distance(.)
I know this is really bad, but maybe someone has any idea:.
The link to the data (18k rows...) is here: https://geoportal.bafg.de/inspire/download/reporting_units/riverWaterBodyForWFD/datasetfeed.xml