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In delineating watersheds, I use publicly available terrain data. I usually opt for ALOS 30m, but sometimes have to compare with SRTM 1 and 3-arc-second resolutions to see which is more accurate at representing the rivers/streams for a certain project area.

I would like to somehow calculate statistics as one would do when calibrating model outputs to observed data. Is this in any way possible on vector line data?

To illustrate what I'm trying to achieve, see below. The light blue (cyan) line is the river I drew by hand in Google Earth for reference which is my "observed data". The pink (SRTM) and orange (ALOS) lines, are rivers delineated in Global Mapper using the "Create Watershed" tool.

How can I determine which river, pink or orange, more closely resembles that of the observed Google Earth River?

enter image description here

The rivers are pretty close in the grand scheme of things, but I would like the assurance that I'm using the most representative DEM for the area in question without having to guess or go through entire reaches meticulously.

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  • Have you tried typing into the search box of this forum "comparing rivers". lots of relevant Q&A...
    – Hornbydd
    Commented Jan 24 at 14:22
  • Just tried it. Cannot seem to find something specific to my question.
    – Chané de Bruyn
    Commented Jan 24 at 14:38
  • For a given stream segment try calculating the RMSE on the coordinates. You will need to figure out how to match coordinates, perhaps by a distance threshold, otherwise this is something that could be done in a spreadsheet.
    – Jeffrey Evans
    Commented Jan 24 at 14:52

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