Question

Splitting lines with points is creating very slightly different coordinates when they should be the same?

  • 6 December 2021
  • 2 replies
  • 3 views

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I'm using a point on line over layer to split a long line into sections, I then need to create start and end points of each section. Simple process i've done a million times. This particular output needs to have the coordinates identical at the start/end of each section, theoretically they should be as they are split by the point at that location. The measure values are coming out identical, but some lat/longs are coming out wrong to the 9th decimal place - the issue is that its only a handful and so i'm not sure whats causing it. Any ideas?


2 replies

Userlevel 6
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Probably caused by the floating point precision issue? I think you should work in a projected CRS to do this very precise. Also 9 digits precision in lon/lat... see XKCD.

 

Maybe this can be fixed using a AnchoredSnapper? But not sure.

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Yeah, unfortunately because of the nature of the work it has to be completed in lat/long as the data crosses multiple Australian MGA zones and the reprojection back and forth would be a bit much. You are correct though, I blew out my point tolerance to 0.000000000001 or something similar and it has fixed the problem for now.

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