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

learn more… | top users | synonyms

2
votes
1answer
61 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
21 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
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 ...
0
votes
1answer
28 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 ...
2
votes
0answers
14 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
33 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
54 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
69 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
79 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
140 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
177 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" ...
1
vote
0answers
43 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
45 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
134 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
152 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
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 ...
0
votes
0answers
21 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
43 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 ...
0
votes
0answers
28 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
81 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
215 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. ...