topic Re: An arcpy solution for randomizing overlapping points within a shape? in Python Questions

An arcpy solution for randomizing overlapping points within a shape?

BrianBowers1 — Sat, 22 Jan 2022 01:18:41 GMT

I have a shapefile layer with polygons for the 50 U.S. states ("States"). I also have a point featureclass with potentially many overlapping points at the centroid of each state polygon ("Dots").

I want to use the CreateRandomPoints_management() function to find new placements for all the points in each state, essentially creating a 1:1 dot density map with clickable point features.

Here's the workflow I have envisioned:

Loop through and select each state, one by one
Get the count of points contained within each state polygon boundary
Use CreateRandomPoints_management to generate count number of randomized points within each state boundary
Move the original points to the new random locations and then delete the random points layer -or- Add fields and assign values to the newly created random points layer from the original points [Whichever's simpler and more reliable]

I've tried several times to write this code, but my arcpy chops aren't that great yet. Any ideas or examples would be greatly appreciated!

Re: An arcpy solution for randomizing overlapping points within a shape?

JayantaPoddar — Sat, 22 Jan 2022 02:03:38 GMT

Solved: Re: Dispersing geocoded points within a Polygon - Esri Community

Hope the following script works for you (Courtesy @XanderBakker and ArcPy Team)

#------------------------------------------------------------------------------- # Name: Disperse3.py # Purpose: Disperse points in multiple polygons # Author: arcpy Team # http://arcpy.wordpress.com/2013/06/07/disperse-overlapping-points/ # Created: 02-dec-2013 #------------------------------------------------------------------------------- import arcpy import random def main(): fcPoints = r"C:\Project\_Forums\Disperse\test.gdb\points3" fcPolygon = r"C:\Project\_Forums\Disperse\test.gdb\Polygons" arcpy.env.overwriteOutput = True with arcpy.da.SearchCursor(fcPolygon, ("SHAPE@")) as cursor: for row in cursor: polygon = row[0] disperse_points(fcPoints, polygon) del row print "ready..." def point_in_poly(poly, x, y): pg = arcpy.PointGeometry(arcpy.Point(x, y), poly.spatialReference) return poly.contains(pg) def disperse_points(in_points, polygon): lenx = polygon.extent.width leny = polygon.extent.height with arcpy.da.UpdateCursor(in_points, "SHAPE@XY") as points: for p in points: if point_in_poly(polygon, p[0][0], p[0][1]): # I changed code here! x = (random.random() * lenx) + polygon.extent.XMin y = (random.random() * leny) + polygon.extent.YMin inside = point_in_poly(polygon, x, y) while not inside: x = (random.random() * lenx) + polygon.extent.XMin y = (random.random() * leny) + polygon.extent.YMin inside = point_in_poly(polygon, x, y) points.updateRow([(x, y)]) else: pass # don't update location if point doesn't originally falls inside current polygon if __name__ == '__main__': main()‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

*Change the path of the point and polygon feature classes in Line No. 13/14.

Re: An arcpy solution for randomizing overlapping points within a shape?

BrianBowers1 — Sat, 22 Jan 2022 11:10:15 GMT

Thanks, Jayanta! That function does look like it might do what I need.