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Questions tagged [point-in-polygon]

Algorithm for determining whether a point is inside a polygon. Normally calculated by counting the number of polygon line segments that a ray from the point intersects.

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Point in Polygon Hit Test in JavaScript (Chrome bug)

I am working on a game written in javaScript / jQuery. Part of my code draws a random polygon (an island) on a tile grid. I need to check if a point is inside the polygon. I am using a point-in-polygon intersection script which I found in several…
shipshape
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Point in rectangle

What is the fastest way to find if a point is in a rectangle given in this form: I have two points which are the centers of opposite sides of the rectangle, and a number which is the height of those sides. I hope this is clear. The rectangle is…
Baruch
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Why is Triangle.Net not triangulating these polygons as expected?

I've been having issues with triangulating certain polygons with holes using Triangle.Net. The issue seems to be certain circumstances where I define a hole using a contour and setting hole to 'true' (after first adding the outer contour, hole set…
Mark C
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Testing whether a 3D point is inside a 3D polyhedron

Given a 3D polyhedron defined by its boundary represented by a triangulated mesh, how can I implement an algorithm that determines whether a given 3D point belongs to the interior of the polyhedron ?
isifzade
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python: turn polygon into mask array

I have a polygon which I want to turn into a mask array, such that all points that fall inside/outside the polygon are True/False. I thought I found the perfect solution (SciPy Create 2D Polygon Mask), but for some reason this doesn't work! What am…
flotzilla
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Deciding if a Point is Inside a Polygon

I am trying to detect if a given point(x,y) is in a polygon of n*2 array. But it seems that some points on the borders of the polygon return that it's not include. def point_inside_polygon(x,y,poly): n = len(poly) inside =False p1x,p1y…
Rabih Assaf
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Finding if point is in 3D poly in python

I am trying to find out whether a point is in a 3D poly. I had used another script I found online to take care of a lot of the 2D problems using ray casting. I was wondering how this could be changed to work for 3D polygons. I'm not going to be…
fatalaccidents
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Point in polygon algorithm for SQL Server

I'm trying to write a SQL query which determine if a given point is into a polygon. (I'm using SQL Server 2008 R2). I was following this tutorial (just copy / paste it and change some table name) and it approximatively works BUT it is not precise…
AlexB
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CGAL tools: is there an interface to CGAL, or equivalent toolset in R?

I'm starting to learn about dealing with complex vs simple polygons, determining whether points are inside/outside polygons, etc. (e.g. http://geomalgorithms.com/a09-_intersect-3.html and related pages). I was hoping to find an R package that…
Carl Witthoft
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check if a point is in a polygon which is partially open

I would like to see if a point is in a polygon or not. Of course I googled and looked if this question was answered earlier and then found this algorithm: http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html This works fine unless…
Folkert van Heusden
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Determine if a latitude/longitude is within a polygon on Earth's surface

I am trying to figure out if a latitude/longitude point is contained within a polygon defined by vertexes that represent points on the earth (also lat/lon's, in clockwise order). This is trivial for polygons that can be mapped to the 2D lat/lon…
BigBrownBear00
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What would make the point in polygon algorithm only work correctly when run in both forward and reverse?

The most popular answer I found for "point in polygon algorithm for c++" seems to be this C algorithm: https://wrf.ecse.rpi.edu/Research/Short_Notes/pnpoly.html However, when I implemented this in my program, it was not able to work correctly for…
Bruce Kirkpatrick
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Find in which polygon a GeoJSON point lies in, in NodeJS

Given a defined (lat, lon) geo-point I'm trying to find in which polygon this point lies in. I suppose iterating over all the polygons is not efficient. Is there available any function or library for NodeJS that does this? const polygon =…
João Pimentel Ferreira
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Does Redis geo have the capability for storing polygon?

I followed several example about geospatial support in Redis. I tried to add POINT features to my Redis dataset without any problem, and subsequently I can query POINT names within certain radius (in meters, km, miles) of a certain coordinate (or a…
Rino
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Change the position of points inside a polygon with Shapely in Python

I want to change by a little the position of some points that are randomly generated inside a Shapely polygon and so far what I use is this: point_on_polygon = False while point_on_polygon == False: y=uniform(0,1) …
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