A common GIS operation. Used to determine whether a point lies within a polygon's bounds.

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2
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55 views

What is the MS SQL Spatial syntax for counting points within polygons? [duplicate]

All, What I'm trying to do is this: Count points within polygons There are thousands of points and maybe 2 dozen polygons Get a list back of the 2 dozen polygons by name and the count of points ...
0
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1answer
1k views

How to extract polygon location data (County) to a point shapefile (only has DMS)

I have imported an excel spreadsheet to my map and the points have fallen into certain locations. How do I add the location of the polygon that the point has landed in, to the attributes table of the ...
1
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0answers
151 views

Can I get a list of points in a polygon using Quadtrees?

I'm storing vertices in a PR (or PM if needed) quadtree and would like to be able to: Find out if a given polygon contains at least one point Optionally: Get a list of all the points within a ...
1
vote
1answer
90 views

Finding point in polygon

I want to calculate a point in a polygon, if the centriod falls inside the polygon it is what I want, but if it doesn't I would like it to be a visual center point. Essentially I want to do the ...
1
vote
1answer
130 views

Add buffer only on one specific side of polygons

I have a shapefile with multipart geometry (multipolygons), namely communities (blue on the picture below). There are also lakes (white), but for these I don't have a geometry, they're just "empty". ...
0
votes
0answers
213 views

Point in polygon analysis fails with “TypeError: arguments did not match any overloaded call”

I am using QGIS 1.8 on Windows 7 I want to perform a point in polygon analysis using the Vector > Analysis Tools menu. My point layer is the result of a SpatiaLite query which returns 10'000 points. ...
2
votes
2answers
995 views

Checking if Lng and Lat fall inside polygons from ESRI Shape file

I have two input files. First: CSV file with a list of points each defined with Lng, Lat, Name Second: ESRI Shape file defining a number of polygons I would like to determine for each point I have ...
3
votes
2answers
116 views

How to query for a specific point, within a specific polygon?

I have a shapefile points layer, with each point representing either Marginal, suboptimal, or optimal conditions. I want to find only the marginal points within a specific polygon from my catchments ...
2
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0answers
139 views

ray casting on earth's surface

Is it safe to use ray casting algorithm to check if a coordinate is inside a polygon specified as coordinates? Purpose of my question is because the longitudes are not parallel in a Cartesian sense, ...
2
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0answers
175 views

How can I improve my Ray casting algorithm?

I have been using the following function below which have been working well to decide if a point in the polygon but once I have many points which is building the polygon say over few thousand it seems ...
2
votes
0answers
127 views

Matching points in table to polygons

this is my first post to this forum. I hope to start participating actively. I have a table with several records (aprox 200.000), each with its own coordinates. And I need to identify the "Polygon" ...
3
votes
2answers
2k views

Count Points in Polygon with Postgis

I've got a simple problem: I want to count the number of points within a set of polygons. I have a SQL already but it only gives back the gid of the polygone that actually contains points. My ...
4
votes
2answers
1k views

Total of attribute field of point layer per polygon layer

I have a polygon shapefile of many lakes, I also have a point shapefile of locations on those lakes where fish were caught. The point shapefile contains the attributes: Fisherman_iD, Fish_Caught, ...
4
votes
1answer
556 views

MongoDB: Search for polygons which have a certain location

Good day :). I am trying to implement a search feature on MongoDB using Mongoose.js , the short version of which is this: I tag locations on a map as polygons. and give them names. Then when an user ...
1
vote
2answers
456 views

Function for Selecting Points in a Polygon

I've been banging on this for a few hours, but since I'm relatively new to PostgreSQL and PostGIS, I can't find the solution. I'm trying to create a stored procedure (function) which will return all ...
0
votes
1answer
53 views

Display county for random points

I have a county level shape file for South Carolina. I generated random points using Vector->Research Tools-> Random Points. The Attribute tables for the random points layer has only the ID included. ...
2
votes
1answer
306 views

Tearing in ggmap (R) after using spTransform and random point generation using splancs

I am using R and the package ggmap to try and generate some random points within the city limits of Chapel Hill, NC. I have downloaded the shapefile for the town of Chapel Hill from the Orange County ...
5
votes
1answer
445 views

How to determine optimal windmill placement to maximize production?

How can I add automatically the maximum number of points (dots) with 6m diameter and 100m distance each point from other into an area. The dots will present the windmill base (6m) and I want the ...
4
votes
1answer
2k views

STIntersects - Update field to give me count of points in polygon

I have a points layer (dbo.ptLayer) Around 1M points Spatial Geometry Type (dbo.ptLayer.geom) No spatial index just yet, but will create one once data gathering complete. I have a polygon layer ...
1
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0answers
242 views

How to update polygon field with point count for multiple rows? (Temporal point-in-polygon)

I have a shapefile with several regions. It contains basic info like ID, Code, Name1, Name2, etc. It is overlaid with a shapefile of points (nearly 200k). Each point represents an event with a type ...
5
votes
3answers
4k views

Check if lat/long point is within a set of polygons using google maps

I know how to do the above using Esri (Query task on shapefile), but can this also be done using Google Maps? Do I have to query each polygon or is there one method to query a set of polygons?
7
votes
2answers
273 views

Update database row with points that fall within polygons

All, I have a PostGIS/Postgresql DB that has two tables in it. One with point geometries and the other that represents country boundaries as polygons. I would like to add the country name that each ...
5
votes
1answer
178 views

Which polygons surround this point? A practical case of political geography

I'm starting a project from scratch but am budget constrained. In plain language I've got no money. What I want is to provide an address and return what governments have jurisdiction there. The ...
0
votes
1answer
161 views

How to add a label of a point to a polygon

i have several polygons with in each polygon a point with a label (number). I want to add the label in the polygon to the attribute-table of the polygon it belongs to.
6
votes
2answers
5k views

Create a polygon layer from point data

I'm currently using QGIS 1.8.0 I would like to create a polygon layer from a point dataset, where the size of the polygons relates to the resolution of the grid reference. The ultimate aim would be ...
2
votes
2answers
2k views

Is it possible to extract Coordinates of Polygon Centroid in QGIS?

I have created polygon centroids using one of the "Geometry Tools" but I would like to extract the actual coordinates into Excel for further work. Is this possible?
4
votes
1answer
2k views

How do I add polygons to an existing attribute table where the data is stored as points? ArcGis 10

I have a shape file of golf courses saved as points, I would like to digitise the boundaries and add the polygons to the existing attribute table. I have opened editor and clicked on the point data ...
3
votes
2answers
211 views

Points in polygon by months

I have two tables: points(gid,id,datum,x,y,geom) and hexa_grid(gid,geom). I must create new table hexa_grid_pip (gid,2008_01,2008_02 ... 2011_12, geom) In column 2008_01 ... 2011_12 must be number ...
1
vote
2answers
311 views

How to implement a spatial query on polygon data for a specific point?

I have vector data fed into a database which returns a report at province level upon querying. This is implemented in a web tool. I want to add an extra functionality at point level, where I can ...
5
votes
3answers
1k views

How to identify feature vertices that are part of a donut hole in ArcGIS 10?

I´m exporting the coordinates of polygon vertices to a CSV-File using the "Feature Vertices to Points" and then the "Export feature attributes to ASCII"-tools. Some of these polygons have holes ...
2
votes
1answer
721 views

How to find most frequent values?

Entry layers: polygons - no attributes (columns/values), points - needed attributes (columns/values) How to get this result?: polygon layer with attribute (column/value) of most often (most frequent ...
1
vote
3answers
3k views

How to check if a point is near or inside polygon?

I am trying to find a simple library which can do point in polygon. Earlier i did hit Java Spatial Index library ...could not figure out. Tried openmap..looked simple didn't work. I am totally new ...
4
votes
3answers
7k views

Solving the Point in Polygon Problem Using Google Maps and Fusion Tables

The Point-In-Polygon problem is fairly well documented on this forum. My question is if there is a way to use Google's free tools, i.e. Google Maps, Fusion Tables, and possibly Google Refine, to solve ...
2
votes
2answers
486 views

Map Coordinates to Neighborhoods from MySQL Table

I have a MySQL database with a set of coordinates and a shape file (Zillow Neighborhood Database for Chicago) containing the boundaries for each neighborhood which I have converted to a spatial ...
4
votes
1answer
660 views

Calculation of average point distances from one another within a polygon grid

I am working with processed LiDAR data of forested areas in ArcMap 10, with various area based statistics extracted for each 30x30m polygon grid-cell in a shapefile. There are approximately 20,000 of ...
2
votes
3answers
1k views

Accessing coordinates of polygon

I have designed a polygon in a web page and the coordinates are stored in the database of the type polygon. However when I check the database, I find GEOMETRY - 120B under polygon field. What does ...
20
votes
2answers
6k views

Looking for fastest solution for Point in Polygon analysis of 200 million points

Apologies for asking a question that has been asked before -- I've read through answers, and I'm left wondering how to implement the recommendations. I've never used SQL, Python, C, and have only ...
6
votes
2answers
2k views

Point-in-polygon using Python and OGR

I want to use OGR in Python to write a simple point-in-polygon test: def point_in_polygon(point, polygon): """ point : [longitude, latitude] polygon : [(lon1, lat1), (lon2, lat2), ..., ...
0
votes
1answer
565 views

CenterPoint of Polygon in ArcEngine .Net 10

I am currently trying to get the center point of a polygon. In GIS, i can see the "x" mark in the center of the polygon, but I do not know how to get it from the IPolygon object. I tried getting the ...
3
votes
1answer
810 views

Correct way to perform point-in-polygon queries on streaming point data?

Short version: What is the "correct" Esri-based solution to the presumably-common scenario of receiving dynamic asset location data (eg. aircraft), checking to see whether those points are within any ...
6
votes
4answers
2k views

Point in polygon algorithm for multiple polygons

I've a Google map with bunch of polygons on it. Here is a problem I'm interested in: Given a lat,lng point, what's the best way to determine all the polygons that this point lies in? The obvious way ...
3
votes
1answer
3k views

How to determine if a mouse click falls within a polygon

I have a polygon drawn on top of a layer using the graphicsContainer of the current activeView, then I want to be able to show a custom context menu if the user right clicks INSIDE the polygon. So I ...
17
votes
7answers
2k views

Fastest way to spatially join a point CSV with a polygon Shapefile

I have a 1 billion point CSV file and a shapefile with around 5,000 polygons. What would be the fastest way to spatially join points and polygons? For each point, I need to get the containing polygon ...
6
votes
1answer
1k views

Performance Gain Through GIST Index for Point in Polygon Query

I have two tables: locations(id,region_id,the_geom) and regions(id,the_geom). For each location point I want to determine the region it is located in: UPDATE locations SET region_id = (SELECT id ...
3
votes
3answers
742 views

In ArcGIS how can I append the number of points that are located inside each individual block groups of the entire US?

I am using ArcGIS 10 and I have 2 shapefiles; (a) a polygon shapefile of block groups of the entire US, (b) a point shape file of customer locations throughout the US. What I want to know if how many ...
5
votes
2answers
575 views

Does anyone know a function to determine if a Point lies on a polyline?

ArcEngine 10 .Net 4 c# Hi I'm currently allowing user to select a point on a polyline and creating a point on the line. I am using snapping tool. I just want to make sure that when the user clicks ...
5
votes
2answers
1k views

Creating polygons from a one to many relationship of points

I have a set of polygons that are in a one to many relationship with points. The polygons are administrative boundaries and the points have information on companies and percentage of ownership . I ...
8
votes
2answers
2k views

Creating evenly distributed points within an irregular boundary

I need to create an evenly distributed series of points within a series of oddly shapped polygons (formerly squares, but now squares with donut holes). The way I have solved this problem so far is to ...
3
votes
2answers
4k views

Select points under polygons?

Dear all, I apologise if this is answered elsewhere, but I cant find it. I have a point layer and a polygon layer (created from the point layer using local convex hull isopleths). I would like to be ...
10
votes
1answer
422 views

Spatial operators in R?

How can I do spatial selections or filters in R? I can do this in PostGIS using (e.g.): SELECT * FROM mypoint, mypoly WHERE ST_Within(mypoint.geom, mypoly.geom); and it is similarly a piece of cake ...