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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3answers
6k views

R function for Thiessen Polygons

For a point data set with temperature data I have, I want to create their Thiessen Polygons in R. So far, the only algorithm I have found is that of Carson Farmer (http://carsonfarmer.com/2009/09/...
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2answers
114 views

Calculating the distance between the furthest vertex of a Voronoi polygon and the point from which it was generated

I need to calculate the distance between the furthest vertex of a Voronoi polygon and the point that generated it. I need to calculate this distance for all Voronoi polygons. Is there a way to do it ...
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2answers
197 views

R - Voronoi polygons from lines

I use R (and sf, mainly) and I was wondering if it's possible to create Voronoi polygons starting from LINESTRING objects instead of POINT. For example, given a sfc such as # package library(sf) #&...
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1answer
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I want to create a Voronoi diagram while retaining the data in the data frame

We will use st_voronoi() to create a Voronoi diagram. I have three questions. Point one. I understand that the argument to st_voronoi() should be the following data. ■SFC format (an error occurs ...
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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 ...
5
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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
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Create mosaic like Voronoi Diagram from disjoint polygons

The illustration below shows the problem: as in (a) I have a set of disjoint polygons, as geometries in PostGIS. I need something like (b), the "mosaic" of this set of polygons, building it by a "...
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1answer
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Voronoi polygons for a layer with point objects, attributes are lost for points with different attributes but same coordinates

I use QGIS v3.4. I have a layer with points where some points has exactly the same coordinates but different attribute fields. When I generate voronoi polygons for this layer the attributes of the ...
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Using Voronoi.Skeleton in QGIS [duplicate]

My purpose is to make a central line from a polygon. For this I use the skeleton algorithm from a polygon, but I did not manage to get a line. I draw the polygon. I launch the program. It doesn't ...
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4answers
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What Is The Ideal Workflow To Map (British) Postcode Territories

I'm looking for the best workflow for mapping postcodes and calculated territories, but being relatively new to mapping I'm struggling on a few details and also the best practices for displaying these ...
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5answers
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Create voronoi diagram from line segments

I'm looking for a way to create a voronoi diagram based on line segments instead of points. See the example below (taken from this presentation). Ideally I'd like something I can script from Python, ...
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2answers
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Thiessen polygon input help

I am new to 10.0 and have never used the thiessen polygon tool -- i have a set of points and would like to create a thiessen polygon; what do i need to input (i.e. what type of input (.shp etc)?
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2answers
885 views

Creating voronoi polygons from polygons?

I have a database with buildings and for some further analysis I need to: aggregate adjacent buildings (preferably without losing the height attribute, but I can work my way around that) once I have ...
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3answers
437 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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0answers
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Create Voronoi with ArcMap

I'm trying to create voronoi map out of a layer pf points in ArcMap (after very long time ot using ArcMap) ,using the geostatistical analyst, but for some reason I get unexpected results: I click ...
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0answers
172 views

Making polygon for every point in set using voronois?

I'm trying to make polygons from points, were each point will be represented by one polygon. I tried using voronois, but the results are incomplete. While I more or less understand where this ...
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1answer
346 views

Voronoi Polygon option?

In Vector > Geometry Tools option, Voronoi polygon option is not there. Do we need to instal any plugin for that?
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2answers
112 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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0answers
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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 ...
2
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1answer
127 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
71 views

Identifying which tracks are too close together?

I have a point shape (yield logging data) and I want to find the tracks that are too close to another track. Usually the combine drives always with the same distance (e.g. 10m). I want to find the ...
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1answer
60 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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1answer
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Growing several concave hulls until they completely fill larger area without overlap using QGIS? [closed]

This is my problem: I have a very large point layer with polling station locations across one country; each point belongs to a specific constituency (900k points, 4k constituencies). I wish to use ...
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2answers
547 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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3answers
2k 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 ...
14
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1answer
5k views

How to use ST_DelaunayTriangles to construct a Voronoi diagram?

(edit 2019) ST_VoronoiPolygons available since PostGIS v2.3! With PostGIS 2.1+ we can use ST_DelaunayTriangles() to generate a Delaunay triangulation, that is a dual graph of its Voronoi diagram, and,...
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3answers
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What does buffer mean in QGIS Voronoi dialog?

Could you explain what "buffer" does in the Voronoi dialog i.e. what does the number stand for?
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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 ...
5
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1answer
254 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'...
2
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1answer
70 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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3answers
1k views

Counting sides or edges of polygon using open source GIS?

I wondered if it is possible to determine the number of sides / edges (not vertices) that a polygon has. Imagine the following case. There is a shapefile with 10 polygons. Is there any way to ...
8
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1answer
975 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 ...
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0answers
149 views

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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1answer
209 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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3answers
207 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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2answers
299 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\...
2
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1answer
104 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 ...
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0answers
258 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 ...
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1answer
108 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 ...
0
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1answer
111 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 ...
2
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1answer
100 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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3answers
646 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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0answers
540 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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1answer
173 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
585 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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1answer
81 views

Creating new feature point at minimum distance between numerous points using QGIS?

Is there a tool or workflow that can create a feature at minimum distance or equal distance between several points? This is now a QGIS question but to clarify I've attached a couple images to show ...
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0answers
258 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 ...
3
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0answers
79 views

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 | ...
0
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1answer
269 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=...
4
votes
3answers
681 views

Thiessen polygons extend outside of extent of projection

I'm working on a geological project on the past position of continents (in ArcMap 10 Service Pack 5, build 4400). The tool I'm creating in Model Builder uses Create Thiessen Polygons and all input ...