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

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103 views

Points in Polygon results in PNTCNT=NULL

I am trying to use the QGIS (2.6.1) vector analysis tool "Points in Polygon". The points originally came from a KML file and the polygons I created new. I initially had a warning about different CRS ...
2
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1answer
75 views

Positons from GPS lanes inside a polygon

i have a lot of lanes like the orange lanes at the below picture (latitude and longitude values). Now i need all values from each lane inside the red polygon. What is the easiest way to realize ...
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1answer
47 views

Point in zone problem in calculation

I have a strange problem that i believe its because the zone pass through international date line. My goal is to find if a point is within a zone and I use the geoPHP library, everything seems to be ...
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1answer
119 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 ...
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1answer
22 views

cannot get properties of multipolygon - mapbox/leaflet

I'm currently using mapbox with natural earth and geojson to populate a map with multipoygons and custom markers. Each of these has a set of properties and information that I need to display on click ...
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67 views

cross referencing files question

This may be an easy question so please forgive me if it is (or if it makes no sense) as this is all very new to me. I have 3 files that I am trying to cross reference. One file has columns category, ...
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91 views

constrain random points with a polygon in R using sp library

I have a map of London's waterways, which I've grided into a raster dataset to enable me to measure proximity to water from randomly generated points. What I'd like to do please is to constrain the ...
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39 views

Determine when a route enters and leaves a polygon

I have all of the segments of a route from White Horse, YK to Miami, FL. Now I want to determine how many miles I travel in each State / Province. I have Polygons for each State and have been able ...
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153 views

Programmatically selecting features by polygon

Expanding upon this post how could you use QGis to programmatically draw a selection polygon and select features within the polygon? I have been using QgsMapToolEmitPoint(self.canvas), to find and ...
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26 views

Tool to help us re-district?

I work for a mid-sized school district and we unfortunately have to close one of our school buildings. That means that the neighborhoods who've been sending their children to the school that is ...
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43 views

split points evenly to neighboring polygons?

I have a crime location data set, containing geocoded crime location points that have been geocoded to streets and street interactions. I also have a census tract shpfile. What I would like to do is ...
2
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81 views

QGIS's “Points in Polygon” counts zero in every census tract

I am mapping the location of incidents of asthma using QGIS. I would like to count how many points are in census tracts to better understand the areas where asthma occurs most frequently. My map ...
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349 views

Speed up row-wise point in polygon with Geopandas

I have a geopandas GeoDataframe which contains some attributes and a geometry column which is filled with shapely Point(lon, lat) objects. Moreover, there is a GeoSeries which is equally indexed as ...
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30 views

Aggregate nearby points to develop equally sized regions in QGIS

I have a list of 4,500 points (lat, long, unique id, attribute). I also have a service territory which all of the points fall into. I would like to break the service territory (polygon) into 6 ...
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57 views

Match housenumbers on buildings (special case of point-in-polygon-test)

Task with example I'm working with geodata (country-size) from openstreetmap. Buildings are often polygons without housenumbers and a single point with the housenumber is placed within the polygon of ...
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156 views

QGIS assign multiple points data to closest polygon

I've got two layers: point layer polygon layer I need to add the points attributes to the polygon by location (if the point is on top of polygon add the atribute as a new field. I thought of ...
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202 views

Using polygons with libspatialindex

I am investigating using some C/C++ libraries for point-in-polygon lookups and libspatialindex seems popular. I've written some code that seems to do what I want but I'm not entirely sure if what I ...
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213 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, ...
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216 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 ...
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179 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" ...
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28 views

How to join points into overlapping polygons layer?

I'm using QGIS and I am relatively new to it. I have a points layer. Each point is the location of a conflict event and the attributes are the type of conflict, year of the event, number of deaths ...
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48 views

Sample points based on underlying polygon attributes

I have a point shapefile and I would like to sample those points (just like the "Sample" tool allows points to sample underlying raster) to receive a table with underlying polygon values (interested ...
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505 views

Geofencing: Query if a POINT is within a POLYGON

I am trying to use the following query to search if a point is within a defined POLYGON (aka a geofence I want to define): ...
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47 views

Arcpy script or other method for points in polygon per participant

Is there an Arcpy script or another way that I could use to find out the number of GPS points falling within each participant’s home neighbourhood as defined by an 800 meter network buffer around the ...
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179 views

How to generally determine if a Point is inside a Polygon/Region?

I have a region (i.e. closed polygon) like this given in cartesian coordiantes: 1: 628497 / 239586 2: 642383 / 249881 3: 657705 / 241262 4: 652677 / 230489 5: 631370 / 231446 6: 628497 / 239586 I ...
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54 views

Using Geoserver

I am new to GIS and interested in using Geoserver. I have had a look at tutorials and read some books on this but still feeling clueless. I intend to use C# to accomplish some tasks eg, plot points on ...
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181 views

node.js GeoLib fails on polygon that straddles the anti-meridian

geolib.isPointInside does not appear to work correctly when the polygon longitudes straddle the anti-meridian. I maintain a system with lots of polygons that do straddle the antimeridian (I'm in ...
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255 views

Divide polygon based on points for even distribution

If I have a point layer, how can I create a polygon that includes all of the points and divide that polygon into n sections in which each section contains an equal number of points? Preferably in ...
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245 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 ...
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265 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 ...
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9 views

How to get all postal code using polygon mapping

I am working with polygon mapping in GOOGLE MAPS API 3. in my application i need to get all postal code (Singapore) between the boundaries which i mapped. can anyone suggest me for any possibilities.
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28 views

Spatial Query - Select features within

Is it possible to know which Point In Polygon algorithm is used when we select points within a polygon? Is it for example the ray-casting algorithm? In addition, is there a definition of the operation ...
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42 views

Number of polygons in shapefile too high

I downloaded administrative shapefiles from www.gadm.com/country (China). The Python (Basemap) code below tells me that there are 2365 polygons in it. However the .csv and .dbf files included with the ...
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60 views

Is there a way to copy attributes from a point layer in an overlaying polygon layer? in arcGIS10

I'm working with an agricultural experimental setup of 450 areas. Each area is represented of a Polygon in ArcGIS and additional with a point Layer. I determined the specific ID for each point but I ...
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47 views

If I use the summary statistics tool to get a count of points within a buffer, how come it provides a value of 1 when that table has no rows?

So I am running a model that provide the number of points within a network buffer. After using the Select Layer by Location tool to select the points, I use the Summary Statistics tool get the count. ...
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73 views

Convert polygons to optimized lat long radius

I have a research project where I need to search Instagram and Twitter for geo coded data. The APIs allow lat, long, and radius, but I have shape files with polygon shapes and some long lines (think ...
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28 views

Point data aggregation for choropleth

I have a sizeable amount of geotagged point data (>1M) and am looking to create a choropleth map of point data density based on boundaries I have in a shape file. I've added this to a fusion tables ...
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129 views

Generate random points in geometry near heatspots

I have an algorithm, that generates random points with in a given polygon (Generate random points in polygon. Algorithm question). The Polygons the points are generated in are communities or districts ...
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39 views

Software to determine if a position is within a shape

I would like to know if there is software available that can: Given a position detected by GPS, Warn the user if they are within a shape that I created and put into a database. Any computer ...
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261 views

Creating a polygon around features

I want to create a polygon around a number of points so that all the points occur within the polygon. The purpose is to do this to a number of different features and see where they overlap.
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536 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. ...