Line distance over contours - Slope length

[WadeLobb]

Hello

I am lazy and hoping someone could help me. I want to work out the true distance of a line taking into account contours. That is although the line is 100m on the flat if I take into account the contour lines I have I imagine the true line distance will be more like 150m.

I am guessing I can use spatial analyst to do this?

[EricRice · Accepted solution]

Hi Wade,

You need a surface (not contours) to calculate this in ArcGIS.  The tool is called Add Surface Information, and for polylines it will return the 3d length (surface length) of the line.  If you do not have the DEM originally used to derive the contours, you can interpolate a new DEM from the contours using the Topo to Raster tool.  Otherwise, just use the original DEM the contours came from.

Best,
Eric