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I have a polygon with a point outside. I was able to calculate the shortest distance between the point and polygon and draw a line for the same. Now, I need to draw radiating lines from the point, on either side of the shortest line, such that they meet the polygon. The shortest line is the reference and the radial lines are decided by angle between them. The angles are theta,2*theta,3*theta etc


I didn't come up with a code for whatever I have managed so far; rather, I used a bunch of functions using arcpy. I'm still in the initial process of understanding the possibilities and what part of my requirement needs custom coding.

The steps that I followed are as follows:

  1. Used Near_analysis to find the nearest point on the polygon from my point. It added the location(X and Y) of the nearest point in the attribute table
  2. Using the coordinates of the nearest point and the coordinates of my point, I implemented the XYtoLine_management to draw the line.

At this point I'm stuck. I've been trying bearing to distance but that uses geographic north as reference.

It not much of a code as it has several errors which are irrelevant, with a few results generated as per my needs.

I'm still exploring some options.

Image describing the geometry

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  • Do you just have one point and one polygon? How many times do you need to do this? I am wondering if you need a script or if you don't have too many you can use the edit tools manually.
    – DMusketeer
    Commented Sep 29, 2016 at 10:34
  • It sounds like you already have some code "to calculate the shortest distance between the point and polygon and draw a line for the same" so I think you should present that to show us what you have tried and where you are stuck.
    – PolyGeo
    Commented Sep 29, 2016 at 10:45
  • You can use plugin "Azimuth and distance" and make lines to your object with azimuth. Then , cut overlapping lines with geoprocessing tool difference, and calculate lenght. I have screenshot but I cannot answer on your question, only comment. QGIS
    – Frodo
    Commented Sep 29, 2016 at 12:22
  • @DMusketeer From one point ill generate those lines at incremental values of theta till some threshold criteria is reached. In this case I will effectively have a triangle with my point and the two points at intersection of the two lines on either side of the shortest distance, with none of the intermediate lines that are visible in the sketch Then repeat this for hundreds of points all around the polygon leaving me with that many triangles with overlapping regions on the polygons I hope that provides enough clarification
    – K_D
    Commented Sep 30, 2016 at 5:06
  • @PolyGeo I have edited the post to explain the process that I employed. You may also refer to my reply to the comment by DMusketeer. Please do let me know if this added information is sufficient. Your guidance is valued. Thankyou!
    – K_D
    Commented Sep 30, 2016 at 5:20

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