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Question

Create polygon from parallel to line

  • Aug 18, 2026 2:24 PM UTC
  • 7 replies
  • 141 views

katta
Contributor
Forum|alt.badge.img+3

Good day, I have a couple of points on a line feature. I would like to draw one polygon around each point, the point serves as center point of the polygon. The polygons should be 1.5m x 1.5m. Two sides should be parallel, two sides perpendicular to the line. See screenshots. What is the fastest way to achieve it ?

7 replies

ebygomm
Evangelist
Forum|alt.badge.img+54
  • Evangelist
  • Aug 18, 2026 2:57 PM UTC

Buffer points by 0.75, use the buffered points to clip the line, then buffer again by 0.75 with end type None (edited as i wrote incorrectly originally)

 


katta
Contributor
Forum|alt.badge.img+3
  • Author
  • Contributor
  • Aug 18, 2026 5:55 PM UTC

 

ebygomm, would you mind to attach the fmw ? I still have troubles to attain the same result. What version of FME are you using ?


DanAtSafe
Safer
Forum|alt.badge.img+23
  • Safer
  • Aug 18, 2026 7:56 PM UTC

​@katta The End Cap Style in the 2nd Bufferer should be “None”

 


redgeographics
VIP
Forum|alt.badge.img+63

Buffer points by 0.75, use the buffered points to clip the line, then buffer again by 0.75 with square ends

 

That’s brilliant!


geomancer
Evangelist
Forum|alt.badge.img+69
  • Evangelist
  • Aug 24, 2026 10:24 AM UTC

Such a simple and elegant solution!

​@katta If this solution works for you, you can mark this question solved.


katta
Contributor
Forum|alt.badge.img+3
  • Author
  • Contributor
  • Aug 24, 2026 6:42 PM UTC

Hi ​@ebygomm , I have a question for some special cases. In this case (see screenshot) I can’t create a polygon parallel to the line because of the change of bearing at the point. How can I create it parallel to one segment only (the segment I want to choose depends on some specific attribute values) ?

 


DanAtSafe
Safer
Forum|alt.badge.img+23
  • Safer
  • Aug 25, 2026 11:07 PM UTC

Hi ​@katta I think you’ll first need to test if the clipped line is straight or not. I’ve done this with a LineCloser, AreaCalculator, and a Tester.  If it’s area is GT 0, then the line isn’t straight and the Chopper reduces the clipped line to line segments, then the Sampler takes the first segment and the LineExtender extends it enough to cross the first round buffer.