Questions tagged [voronoi-thiessen]

Thiessen polygons are polygons (generated from a set of points) whose boundaries define the area that is closest to each point relative to all other points. Thiessen polygons are mathematically defined by the perpendicular bisectors of the lines between all points and are created by means of a triangulated irregular network (TIN) structure.

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4
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2answers
64 views

QGIS Voronoi polygons wrong behaviour

I am trying to use Voronoi polygons algorithm in QGIS in a dataset of points but strangely I am getting an overlap of polygons. These points correspond to the vertices of a set of polygons. When ...
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Combining cost analysis and voronoi-like area interpolation regarding slopes

I have DEM raster data of an island and I have 10 points (cities). My task is to map the island into areas. Inside these areas everything must be nearest to the corresponding city/point, and each ...
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3answers
175 views

Insert n points equally distributed into many polygons

I know the "Random Points inside Polygons" tool in QGIS. It generates the below output. What I want to achieve however are 8 equally distributed points for each of the polygons. I thought of dividing ...
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1answer
47 views

Creating Voronoi diagrams using JTS and the manhattan or minkowski distance metrics

In Java I am using the JTS library. Is it possible to use this library to generate Voronoi sites using different types of distance functions? https://locationtech.github.io/jts/javadoc/org/...
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1answer
38 views

Find the side of a polygon pointed by an azimuth

I have a dataset of points (longitude, latitude) and I used QGIS get a Voronoi diagram of these points. Each point has an azimuth and a wedge width that I also managed to visualize in QGIS. As you ...
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2answers
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GRASS GIS: Computing center line of raster feature representing a river

My goal: Convert a raster layer representing a river feature (see picture) to the center line of the river stored as a polyline feature. Limitation: The whole process has to be automated. I can ...
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3answers
1k views

Voronoi Diagram on a given polygon using QGIS

I am trying to create a Voronoi Diagram on a specific polygon, but there is some issue when dealing with edges. Here is how I do it: Preparing the points for Voronoi and the polygon for the diagram ...
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27 views

Creating polyline between points using ArcGIS Desktop?

Using ArcGIS Desktop, I am trying to create a frontline of a battle from WW2. I have known points, and want a polyline to run between both sides. There is 87 days of combat, so every day there is a ...
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1answer
52 views

average weighted value by region with use of Voronoi in Qgis

I have a vector layer of Voronoi polygons. This layer has three columns -longitude, latitude, Z-value. I need to cut polygons by mask of administrative area and then I need to calculate average-...
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1answer
145 views

Create a line string from street geometry

I'm currently facing some hard times trying to create a simplified line from a street geometry. The data that I'm currently using comes from OpenStreetMap, using osm2pgsql.(Which means PostGIS, but I'...
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38 views

Making different classes create different size buffers/Thiessen polygons based on point data in ArcGIS ModelBuilder?

Is there a way of getting point data with different classes/numbers create different buffers/Theissen polygons in ArcGIS ModelBuilder? For example: If two points are plotted on a map with the ...
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50 views

Thiessen Polygon around groups of points

I am trying to build Thiessen Polygons (Voronoi) from addresses. I have converted addresses to GPS coordinates and i can build the polygons with the python scipy.spatial.Voronoi library. However, I'm ...
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Voronoi polygons tool not working in QGIS

So I've been trying to build up some Voronoi diagram out of my point dataset but I can't seem to get it to work. When I try it on QGIS 3.4 I get the following error: Traceback (most recent call ...
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3answers
148 views

QGIS 'Voronoi polygons' freezes with 500k points

I've been using the 'Vector geometry--> Voronoi ploygons'function in QGIS to create voronoi cells for 200,000 points with success. However, recently I am working with a bigger point set (500,000 ...
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0answers
175 views

Save output from runalg in PyQGIS

I try to use the build-in Python-console of QGIS to create voronoi skeleton lines from a set of polygons. Therefore I iterate over the features of my input layer (the polygons) and then I use the ...
7
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2answers
296 views

Constrained Voronoi polygons QGIS

I have a shapefile of polygons, which are effectively borders of a geographic unit (consider as an example the 50 u.s. states, each state has within it some number of points.). I'd like to create ...
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1answer
86 views

Adding vector layer and newly created layer always in Top- Down Order Panel using Pyqgis 3 [closed]

I have two layers in my project Point Layer Building Layer I recently created Voronoi Polygon on Point Layer say (vor-points layer) But as soon this Happen, the newly created vor-points layer ...
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1answer
100 views

Constructing Voronoi Polgon and Applying Nearest neigbour in it

I am learning QGIS 3.XX and currently working on Voronoi Polygons. I have three layers Point layer Building Layer Population CSV file. These points layer are basically water tanks and building ...
2
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1answer
86 views

If rectangle corner points have same nearest neighbor, does whole interior?

If all four corners of a spherical (but actually WGS84/elliptical) rectangle are closest to a given point p in a set S, does that necessarily mean all points inside the rectangle are also closest to p?...
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1answer
89 views

Voronoi polygon strange result

I am using QGIS 2.18.21. The attribute table of my shapefile has 88 features but after creating the Voronoi, only 86 are in the attribute table and all the points are showing inside the Voronoi ...
2
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1answer
119 views

Count the number of points in each Voronoi polygon

I have a Data.frame consisting of Longitude and Latitude called Points1, with which I use Voronoi polygon. I also have another Data.frame of Longitude and Latitude called Points2. I then want to ...
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1answer
425 views

Choropleth map from voronoi map from a set of coordinates (d3+leaflet)

I have a csv file with a set of coordinates with the following structure: id,name,latitude,longitude (24 values). Those 24 points represent coordinates in a city. I would like to get a voronoi map ...
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214 views

How to generate a Global Voronoi diagram?

Using arcMap, QGIS and similar software it is easy to create a non-global Voronoi diagram. The resulting shapefile polygons however are showing weird behavior when crossing the -180 meridian or the ...
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PostGIS global Voronoi Thiessen Diagram Polygon

I am trying to create a global voronoi diagram for three points (cities): Miami, Boston and Honolulu. The geom column contains the points created by x and y.: | index | name | x | ...
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2answers
258 views

No Voronoi polygons created

I want to create the Voronoi diagram from a set of point (see below). When I use the "Voronoi Polygons" tool from QGIS, there is an error : File "C:/PROGRA~1/QGIS3~1.0/apps/qgis/./python/plugins\...
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3answers
617 views

Growing polygons with limiting area and boundary using ArcGIS Desktop?

I need to create polygons of a specific area based upon random points within bounding polygons, but haven't been able to find a tool able to do all these. I've looked at growing Theissen polygons, ...
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1answer
88 views

Symbology: different ways to display categorised data QGIS 2.16 [closed]

I have a database of 100 entries which has been categorised using a column of data that has 20 categories which essentially breaks up my map into 20 regions. I'm seeking advice on ways how to create ...
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3answers
355 views

How can ST_VoronoiPolygons be used instead of the broken built-in algorithm in QGIS?

I tried to use QGIS to create voronoi polygons from a set of points with an attribute (group) and then merge the polygons with the same value for that attribute. (This last step is what QGIS calls ...
4
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1answer
152 views

How to define voronoi polygon buffer extend in QGIS from layer extend

I'm using QGIS (2.8.1) Voronoi Polygons Algorithm and I would like to extrapolate them to a polygon layer extend. In order to do this, the tool opens a window asking me to enter a number or expression ...
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0answers
186 views

Voronoi Polygon Algorithm seems to exclude a Point from processing

I am using the QGIS (2.8.1) Voronoi Polygons Algorithm on a point shapefile. See image below, the red triangles are the points I am using. The resulting polygons miss a part (around HP87). Any ...
4
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3answers
580 views

Strange results with Voronoi polygons in QGIS

I'm trying to generate a Voronoi Diagram in QGIS 2.14.3 from 16 points. The result looks very strange, at least compared to what I expected. For me, at least the two yellow highlighted split are ...
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478 views

Determining areas on a Voronoi Diagram around a point

I currently have two data sets concerning the Netherlands, one containing longitudes and latitudes of population cores (Hubs) along with other information, such as average house price, and the other ...
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0answers
225 views

ST_Voronoi is creating invalid geometries

I have a workflow where I am creating Voronoi polygons from a series of points. However since the polygons on the exterior extend really far out I have clipped them and then joined them back to points ...
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1answer
588 views

Splitting overlap between polygons and assign to nearest polygon using PostGIS?

My question is quite related to the unanswered Split overlap between polygons into disjoint sets except I'm not using shapely, I'm using PostGIS 2.4 on PostgreSQL 10. I have a table containing ...
2
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1answer
128 views

Thiessen Polygon - geotools

I need to create Thiessen Polygon from a point collection and then intercept them with other polygons. I need to do this from a java program. I'm using the Geotools library. I was able to load the ...
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200 views

how to create thiessen polygon around specific areas of interested area? [closed]

I wish to create Thiessen polygon within all sub_basin of my interested area individually, meaning that to create Thiessen for every sub_basin one by one. I have to layer one is point layer and ...
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1answer
72 views

How to fit census tracts within Voronoi Polygons?

I have a map with Voronoi polygons and I need to join census data in it. The problem is that the geometry of voronois and census tracts (CT) do not match. My goal is is to place census tracts (or ...
9
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1answer
415 views

Voronoi that don't cross boundaries

I have several dozen points plotted across the UK. Each point represents a facility that serves local people. To estimate the catchment areas of each facility I created Voronoi polygons around them, ...
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0answers
180 views

Constraining Voronoi polygons to other layer using FME?

Using FME 2017.0.1.1 (Build 17291) is there any way to constrain the extent of created Voronoi polygons to polygonal features of another layer? Instead of clipping the Voronoi polygons after creating ...
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1answer
208 views

I don't understand how v.voronoi GRASS module works with flag -a

I'm trying to use v.voronoi with flag -a. An example in the manual shows Voronoi diagram for urban areas but each try returns: v.voronoi -a --overwrite --verbose input=...
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0answers
170 views

Fill in spaces between polygon features, voronoi style

I'm looking for a way to merge polygons across the empty space between them with a Voronoi-type result. There is a very similar question here, but the approaches outlined in the comments did not ...
4
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1answer
2k views

How To Use ST_VoronoiPolygons() in PostGIS?

Sorry folks, I know it sounds like a lame question - and, yes I did read the manual... :-) I'm trying to make Voronoi diagrams around points I have in a PostgreSQL table. It should be rather easy - ...
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4answers
876 views

Calculating Voronoi Diagrams for polygons

There are a variety of good algorithms for generating the Voronoi polygons or their complement, the Delaunay Triangulation for a set of points. My question is simply, is there an algorithm for ...
5
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1answer
414 views

Flood fill formula for Voronoi cells on QGIS?

At the moment, I'm developing a map of a fictional West Indian nation with QGIS. Everything's gone as well as can be expected with this project--except for a shortcoming that stumped me on Thursday ...
4
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2answers
999 views

Which tool or plugin for Theissen / Voronoi polygons in QGIS?

As I understand you can generate Voronoi polygons in QGIS (2.18.2) using the following approaches; Vector menu / Geometry tools / OR MMGIS plugin in I also read here that you could use SAGA as well. ...
4
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2answers
596 views

What is math behind entropy calculation in ArcGIS Voronoi diagram?

ArcGIS for Desktop 10.3.1, Geospatial Analyst Toolbar, Voronoi Diagrams How is the entropy value calculated? What is the math? I have gone through ESRI's E-learning exercise. The exercise has a data ...
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0answers
170 views

How to calculate the distance from the point to the raster' boundary in qgis

As the picture 1 shows,I use the points generate the Voronoi diagrams and change the polygons to the raster.The purpose of me is to calculate the min,max and mean distance from points to the raster'...
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1answer
499 views

What alternative to Voronoi polygons should I use for my QGIS problem? 2d Clustering?

I have a table with all the hotels in Paris. The columns are the name of the hotel, the geocode and the neighborhood (arrondissement) of Paris that hotel is in. I've plotted all these points in GQIS ...
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0answers
624 views

How to Create Voronoi Polygon Diagram within surrounding polygon?

I want to create a Voronoi Diagram within an outer polygon. I want to retrieve a result very similar to this solution, which uses ST_DelaunayTriangles() to create Triangles. Actually, it would ...
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0answers
95 views

Automate CSV to Point Layer to Polygon (Voronoi) on QGIS (Mac or Windows) [closed]

I have a map I update on a monthly basis, following these steps: Import new CSV with lat/long and other values as point layer Generate Voronoi polygons for the point layer Clip the Voronoi polygons ...