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I have a file with polylines digitized in several directions (clockwise and counter-clockwise) and I need them to be all digitized in only one direction. This I have solved with creating coverages and then back to lines again. Then I have dissolved them by Z value to get rid of short line pieces or duplicates that somehow appear.

Now I would like to find out actually how many of those new lines have been "fixed" - direction changed from false to correct. Feature compare works on simple and exact duplicates (geometry change), but when the line has been merged for example, then it immediately gives geometry error or as is with my previous solution - the endpoint isn't the same any more and geometry is different.

Is there a solution?

Polylines are contours. More precisely depression contours. They are represented by "ticks" showing the direction of descent. The system representing them is locked, so the depressions have to be made according to this, but errors happen... a lot. Left is digitized counter-clockwise and right is digitized clockwise. Left is correct.

Left is digitized counter-clockwise and right is digitized clockwise.

I haven't found any tool that could find which closed contour is digitized wrong or correct, only thing that has helped is the conversions. But now I need to start finding how many of these errors occur and I thought that if I can't find the errors themselves, I can find how many objects have changed.

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  • If you have dissolved polylines into each other it is not surprising that feature compare tool is not reporting similar geometries. May be a better approach is to select the polylines that are in the wrong direction and flip them and as you have them already selected you could update some flag field.
    – Hornbydd
    Dec 8, 2016 at 17:12
  • You don't say what these lines represent, there may be an elegant solution if say they are rivers... Suggest you amend your question with some images of before and after.
    – Hornbydd
    Dec 8, 2016 at 17:13
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    If they have common IDs preserved, you might use add geometry tool to calculate bearings and compare them after joining original to result
    – FelixIP
    Dec 8, 2016 at 19:17
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    @FelixIP, I think you should add this as an answer.
    – Fezter ♦
    Dec 8, 2016 at 22:22
  • What I do to check witch direction they were digitized I change the symbolization to a line with an arrow to the right. If that's what you want?
    – Kokod
    Dec 10, 2016 at 2:30

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As commented by @FelixIP:

If they have common IDs preserved, you might use add geometry tool to calculate bearings and compare them after joining original to result

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