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

learn more… | top users | synonyms

2
votes
1answer
72 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 ...
1
vote
1answer
31 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 ...
1
vote
1answer
40 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 ...
1
vote
1answer
108 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 ...
0
votes
1answer
56 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, ...
0
votes
1answer
46 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 ...
0
votes
1answer
34 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 ...
3
votes
0answers
120 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 ...
2
votes
0answers
58 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 ...
2
votes
0answers
25 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 ...
2
votes
0answers
51 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 ...
2
votes
0answers
126 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 ...
2
votes
0answers
138 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 ...
2
votes
0answers
173 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
votes
0answers
193 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
159 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" ...
1
vote
0answers
38 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 ...
1
vote
0answers
195 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): ...
1
vote
0answers
122 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 ...
1
vote
0answers
42 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 ...
1
vote
0answers
121 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 ...
1
vote
0answers
53 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 ...
1
vote
0answers
123 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 ...
1
vote
0answers
187 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 ...
1
vote
0answers
201 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
0answers
258 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 ...
0
votes
0answers
43 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 ...
0
votes
0answers
40 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. ...
0
votes
0answers
42 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 ...
0
votes
0answers
16 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 ...
0
votes
0answers
79 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 ...
0
votes
0answers
34 views

Capturing points slightly out at sea

I have two tables one containing points (points) and the other polygons (polygons). I want to generate a two-columns table identifying for each point of the first table the polygon containing it. So ...
0
votes
0answers
35 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 ...
0
votes
0answers
135 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.
0
votes
0answers
390 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. ...