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.
Questions tagged [point-in-polygon]
275 questions
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Determine in which polygon a point is, and then apply the name of that polygon as a new column to a large pandas dataframe
I have a large dataframe containing location data from various ships around the world. imoNois the ship identifier. Below is a sample of the dataframe:
and here is the code to reproduce it:
# intialise data of lists.
ships_data =…
oikonang
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How do I determine if a series of points (or polygon) is within a rectangular region?
I have been looking at posts about determining if a point lies within a polygon or not and the answers are either too vague, abstract, or complex for me. So I am going to try to ask my question specific to what I need to do.
I have a set of points…
jpwrunyan
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Plotting pixels and contours when XY coordinates are known
I am using Open CV in python and I extracted some points from contour and pointpolygon test operation. (I basically used pointpolygon test to check if some pixels are inside a contour or not).
Now I got the points but I want to visually confirm if…
PagMax
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create polygon for a route using latitude and longitude
I am having a predefined route as a set of locations with latitude and longitude. I want to create a polygon by using these co-ordinates and want to know when the user deviates from it.
Anyone have any tips or sample code to draw a virtual fence…
Manu
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Point-in-polygon in spatial sql without cross join (oracle with sde)?
I would like to do a point in polygon test using spatial SQL (DBMS Oracle with SDE for spatial tables). I have a spatial, materialized view containing points and I would like to add the polygon ID (from a different table) in which a point lies to…
faebel
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Changing polygon points in SVG for radar chart in Microsoft Powerapps
I am developing a radar chart in Microsoft Powerapps. When pressing a button the chart must change. Since radar charts are not supported I create one myself using a SVG image. By pressing the button the SVG polygon points must change so it matches…
Jan Zandbergen
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How to determine if a point is existing in only one polygon not in adjacent/other nearby polygon?
I am using an algorithm given here(many others are also using It). But in my scenario for some specific point, it is showing intersections at more than one polygons.
I am using php and imported geojson in mysql. and using below code…
Furquan
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Creating a centroid column from geometry shape field produces AttributeError: 'NoneType' object has no attribute 'centroid'
I have imported a shape file of Australian local government areas (LGA's) into google Colab and successfully read into geopandas. The subsequent geodataframe
lga_df = gpd.read_file("LGA_2016_AUST.shp")
has a geometry field with a list of polygons.…
George Deubler
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How To Find a Point In Polygon from a Geojson file Using Python And Geopandas
So I have a .geojson file that contains a FeatureCollection of multiple polygons representing a country. I am trying to determine if a specific point is inside one of these polygons. If so, I return the entire feature itself; if not, I return a…
AllJs
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St_buffer() giving inaccurate results
I have the following code:
set @lon = 121.4732134;
set @lat = 31.2304321;
set @point = point(@lon, @lat);
set @radius = .5;
set @polygon = ST_Buffer(@point, @radius);
select l.city,l.latitude,l.longitude,
st_distance_sphere(l.latlngindex,…
lmao
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how to efficiently detect and remove non-connecting lines in a shape
I wish to perform a point-in-polygon check but first need to remove redundant lines from the polygon so that I can then carry out a ray-casting algorithm. The polygon is being represented in a 2D binary array (1 for filled, 0 for empty). Redundant…
Philip Eagles
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How to sort/label points by the polygon that they fall in?
I have a lot of polygons (~40k), each of which represent a different city block. I also have a lot of latitude/longitude coordinate points (~700k). Each polygon is labelled and has a unique name.
Is there a way that I can go through each individual…
Naiem
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GeoJSON : Check if a Geo Coordinate is inside Polygon
I have following GeoJSON data file which contains a polygon with coordinates.
[
{
"geometry": {
"type": "Polygon",
"coordinates":
[
[
[
9.137248,
48.790411
],
…
Arun Kumar
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find out a point is in which polygons
I have a region table in oracle 12c, the table include 9 region that each of them defined by a polygon.
Polygon defined by 4 points in 2D.
I give a point from client and I must find out that this point is in which polygon. can anyone help me with…
navid sedigh
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How does the Even-Odd Algorithm count polygon edges?
I am wondering how the even-odd algorithm works for identifying a point in a complex polygon.
What I know right now is that it will do the horizontal search from most left to the point and count the number of edges touched.
However, what happens…
Shing Chi Ng
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