inpolygons

Finds points inside multiple polygons, holes possible.
3.6K Downloads
Updated 23 Sep 2021

inpolygons.m Documentation

Author: Kelly Kearney View inpolygons on File Exchange

This function checks whether a point or points is inside one or more polygons. The polygons can have holes in them. When dealing with a large number of points and/or polygons, this can be faster that inpolygon.m.

Syntax

in = inpolygons(x,y,xv,yv)
[in, index] = inpolygons(x,y,xv,yv)

See function help for description of input and output variables.

Example

We'll start with two polygons: a rectangle with square- and triangle-shaped holes, and a solid diamond:

xv = [1 1 7 7 1 NaN 2 3 3 2 2 NaN 5 6 5 5 NaN 7 8 9 8 7];
yv = [1 4 4 1 1 NaN 2 2 3 3 2 NaN 2 2 3 2 NaN 8 9 8 7 8];

[f, v] = poly2fv(xv, yv);

patch('Faces', f, 'Vertices', v, ...
      'FaceColor', [.9 .9 .9], ...
      'EdgeColor', 'none');

inpolygons1

Now, we scatter a couple hundred random points, and test which polygons they fall into.

x = 10 * rand(200,1); 
y = 10 * rand(200,1);

[in, index] = inpolygons(x, y, xv, yv);
index = cell2mat(index);  % No overlapping polygons allows this.

plot(x(in), y(in), 'r.', x(~in), y(~in), 'b.');
plot(x(index==1), y(index==1), 'go', x(index==2), y(index==2), 'mo');

inpolygons2

Cite As

Kelly Kearney (2024). inpolygons (https://github.com/kakearney/inpolygons-pkg), GitHub. Retrieved .

MATLAB Release Compatibility
Created with R14SP1
Compatible with any release
Platform Compatibility
Windows macOS Linux

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inpolygons

Versions that use the GitHub default branch cannot be downloaded

Version Published Release Notes
1.1.0.1

linked GitHub readme

1.1.0.0

Linked to GitHub repository

1.0.0.0

To view or report issues in this GitHub add-on, visit the GitHub Repository.
To view or report issues in this GitHub add-on, visit the GitHub Repository.