I am trying to measure the width of a polygon every km. I have a center line and a polygon, but am unsure what to do next.

In Estimating river Channel Width using Python/ArcGIS/MATLAB/R? I have read about methods which use create perpendicular transects and then using the intersect tool to measure the distance between the two sides of the polygon.

This seems like a reasonable solution, and I have tried it, but for some reason the "Perpendicular Transects" tool is creating lines which do not appear to be perpendicular to me.

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I am using ArcGIS 10.2 for Desktop.

  • 2
    It is almost always the case that a surprising lack of perpendicularity is due to a miscommunication between you and the computer concerning what coordinate system is being used. Note, too, that the lack of perpendicularity in the map might not necessarily indicate a problem, because the distortion could be due to the map display algorithm alone. Therefore it would behoove you to document the coordinate systems you are using for (a) the underlying data, (b) this calculation, and (c) this map. – whuber Mar 15 '16 at 20:17
  • I am using a local coordinate system. I have checked the center line, the transect line, the environment for the script, and the data frame. Is there anything else I should check? All appear to be in the same coordinate system. Could it be possible that my local coordinate system is causing a problem? – Rhizoblaster Mar 15 '16 at 20:41
  • Please use the edit button beneath your question to revise it with any requested clarifications. Potential answerers may or may not have time to read the comments. – PolyGeo Apr 1 '16 at 5:44
  • For this to become answerable I think we will need you to detail the precise steps you performed to obtain the result illustrated. – PolyGeo Apr 7 '16 at 1:26