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I have a polyline shapefile with streams. I would like to turn this to a raster where there would be a cumulative length sum value in each pixel moving downstream. In other words, this would be an downstream increasing cumulative sum based on polyline length.

Unfortunately though, I'm unable to use DEM for calculating flow direction and do this through normal flow accumulation as the stream shapefile and DEM are slightly mismatching. Another problem is that the flow directions are set to both directions of the lines. Thus, I would like to first reset the flow direction of the polylines and then calculate the cumulative sum straight from the polyline file.

I would need 2 tools for this>

  1. Tool that would redirect the line direction based on the DEM value of the two end points
  2. Tool that would calculate cumulative length from the redirected polyline features.

Is anything like these existing?

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  • It sounds like you explored using a DEM. Why not burn the streams into the DEM?
    – jbchurchill
    Commented Apr 7, 2015 at 13:14
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    The techniques explained in my answers at gis.stackexchange.com/a/11041/664, gis.stackexchange.com/a/13804/664, and gis.stackexchange.com/a/87690/664 can be readily adapted to solve these problems simultaneously.
    – whuber
    Commented Apr 7, 2015 at 15:08
  • How did you get on trying to implement the three suggested techniques to meet your first question/requirement? At the moment your question contains two requirements/questions making it to broad but it sounds like focussing on the first one may solve the second one anyway. If not, it can always be asked separately.
    – PolyGeo ♦
    Commented Jun 11, 2016 at 8:57

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