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 ...

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PyQGIS Processing - wrong number of parameters

I'm facing a very strange issue from the module Processing using it as a standalone (not in the Qgis python console). I'm trying to create voronoi polygons from a points csv file. I can load my file ...
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56 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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20 views

Using angle attribute to split voronoi polygan to three small polygon in QGIS?

I have a point data set, that include [id] and [angle] attribute, like 0/120/240。I made voronoi layer use point, i want to use angle attribute split voronoi polygan to three small polygan, how to do ...
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2answers
89 views

Postcode mapping (QGIS): how to transform OS csv data to an polygon map (.shp)?

I am trying to obtain a full England postcode map (polygons) out of free (and reliable) data out there. The English National Office of Statistics does share a huge list of postcodes and some ...
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1answer
26 views

Scripting a population sum based on union

I'm having trouble automating a process to sum one field into a new field, summing whenever the value of an FID field from my Union is the same. I'm looking to sum the population, stored in field "...
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3answers
98 views

Issues in Intersecting Voronoi Polygons With Other Boundary Shapes (QGIS)

I'm having problems in intersecting Voronoi polygons with another shape. As the image shows, I want to clip the Voronoi layer at the red costal perimeter of the UK so that the additional surface area ...
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59 views

How to draw weighted voronoi polygons ( thiessen) from points in Qgis?

I have a shapefile of polygons which have an amount of population, I need to divide each of these polygons into small ones with nearly equal population. So I thought attributing points on each area ...
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44 views

How to use ST_VoronojDiagram for points that are almost aligned?

I am trying to use the spatialite ST_VoronojDiagram function on a table containing four 4 points that are almost aligned: (1.01 2.02, 2.02 3.03, 10.01 10.02, 11.01 11.02). I wrote the following script ...
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72 views

R: Voronoi tesselation from long/lat data?

I want to create a SpatialPointDataFrame and Voronoi Tesselation from my .csv data downloaded from EPA, available here: http://uloz.to/xboQc7cu/no2-calif-csv I convert my data in SPDF format in 2 ...
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88 views

How to create a shapefile having Voronoi diagrams from the shapefile of an existing region?

I have a shape file of a region and I want to generate random sub regions of that shape file using Voronoi class of scipy.spatial package of python. But I am a newbie to GIS. I found out about Voronoi ...
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1answer
81 views

Where can I find the version of scipy python package used in QGIS Lyon 2.12?

I am using QGIS Pisa 2.10. I want to use the Voronio class of scipy.spatial in QGIS python console. QGIS Pisa has 0.11 version of scipy package. This package doesn't have Voronoi class. I even tried ...
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118 views

Calculating area of intersection of polygon to another layer in ArcGIS for Desktop?

I am very new to GIS, especially ArcGIS. I am currently using ArcGIS 10.2, and I have 2 layer, namely the purple feature map(this layer is an import from arcgis online, it doesn't seems to be an ...
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78 views

The drawing of Thiessen/Voronoi polygon boundaries - are the bisecting lines truly perpendicular?

I am concerned with how QGIS (version 2.8.1) and ArcGIS (version 10.0) draw "perpendicular bisecting lines" when Thiessen/Voronoi polygons are created. When using either program to create these ...
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1answer
30 views

Thiessen polygons modified for slope

I seem to recall to have read about Thiessen polygons which, instead of having straight boundaries, had some irregularly shaped sides. That was since those polygons were actually taking into account ...
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3answers
500 views

Constructing Voronoi diagram in PostGIS

I'm trying to construct voronoi diagram from grid of points using modified code from here. This is SQL query after my modifications: DROP TABLE IF EXISTS example.voronoi; WITH -- Sample set of ...
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1answer
328 views

Split a polygons into many polygons based on points using ArcMap

I have: A polygon feature that is a national park boundary, A multi-point feature that are security guard posts (number = n ) of the same park. I want to divide the national park area into 'n' ...
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188 views

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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80 views

Creating polygons using mask layer?

I looked at this question, but it only answers part of my problem. I want to create Thiessen polygons based off of the green points within the blue polygon boundary ONLY. I've set the Processing ...
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1answer
79 views

voronoi / thiessen different CRS

I have the following problem in QGIS: I try to create voronoi polygons based on a shapefile (points; standard WGS84). The newly created voronoi polygons layer seems to be ok for the WGS84 CRS. But ...
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1answer
131 views

Interpolation from isolines vs Thiessen (Voronoi) polygons interpolation

I'm currently studying GIS and have come across a question in an assignment that I just can't answer. I've been googling my brains out for the last few hours and got nowhere... here goes... Identify ...
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1answer
163 views

QGIS - Level curves - Voronoi Polygons

I am facing a difficulty in QGIS (2.8.2): I have three layers: layer 1: layer with points layer 2: layer of level curves (contour lines) layer 3: layer of Voronoi polygons obtained from the points ...
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215 views

How can I put Voronoi/Thiessen polygons on Google Maps for free with no programming knowledge?

The only thing anywhere close to what I describe in the title is this site: http://lpetrich.org/Science/GeometryDemo/GeometryDemo_GMap.html. It has a couple problems, though: 1. There is no easy to ...
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77 views

Computational Geometry Problem

I have following datasets- Road network (line) Waterbodies data (polygon) School locations (point) Suberb boundaries (polygon) Property boundary -buildings (polygon) What i want- Generation of ...
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45 views

Why when I create Thiessen Polygon it didnt start at middle line beetween two points?

I must asking this, in ArcMap 10.2 why the thiesen poligons didnt divide at median line? it was move at +- 3 meters from the median line. Why is this happening?
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219 views

Add Points shp attributes to Polygon shp by Point location (as Spatial Join in ArcGIS)

I have a set of points in .shp (ESRI, available here: http://ulozto.cz/xGqRVFrR/voronoi-zip). I would like to calculate Voronoi tesselation from the points, thus create polygons. So far, so good. ...
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82 views

Cross validation in thiessen polygons interpolation

I apply Thiessen Polygons interpolation using the krige command in the gstat R package. Using krige without a variogram model sets automatically krige function to perform IDW, and when nmax parameter ...
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20 views

Does fixed classes exist in QGIS?

I'd like to create several images of voronois polygons in QGIS; each images having differents values joined to the voronois. I tried to load a qml style with the values I want to keep (8 classes : 0>...
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1answer
82 views

How to delimit point distances in ArcGIS for Desktop per Thiessen polygon

I have 2 shapefiles. The first set contains x,y coordinates for 1100 hospital locations. The second pair contains x,y coordinates of about 7000 villages that are served by the hospitals. This means ...
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107 views

Is there any way to set a processing extent for QGIS:Voronoipolygon?

I was playing around with the QGIS:voronoipolygons command line function from QGIS and noticed that there was no option for setting the processing extent. This causes QGIS to pick the minimum extent i....
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0answers
66 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 ...
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108 views

Considering “holes” in Voronoi polygon creation in QGIS?

I am trying to create voronoi polygons in QGIS that would consider "holes" in the general domain. An example would be: I actually created the Voronois in this image using QGIS through the GRASS ...
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280 views

How can I create weighted voronoi (thiessen) polygons within a constraining polygon?

I have been experimenting and trying to find a way to create weighted theissan polygons, within a constraining polygon with no luck. I am also not too familiar with python which I am sure is a ...
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1answer
83 views

Fill larger polygon empty space with closest subset of polygons

Looking for an ArcGIS or QGIS solution. I need to divide up the space of the large single green polygon. Each new polygon would represent "nearness" to the purple polygons and have the ID of the ...
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433 views

Create Thiessen polygons using spatially weighted averages? [closed]

I have to create Thiessen polygons with the spatially weighted averages for specific contaminate concentrations from different borings. I have the Thiessen polygons created but this only shows me the ...
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2answers
1k 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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964 views

Polygon of Voronoi cell using scipy.spatial?

I have points (e.g., lat, lon pairs of cell tower locations) and I need to get the polygon of the Voronoi cells they form. from scipy.spatial import Voronoi tower = [[ 24.686 , 46.7081], [ ...
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1answer
630 views

How to use Delaunay triangulation in QGIS?

I have to create a Thiessen polygon for a site in New Jersey and all I have right now is the concentrations from samples we took in the area. What else do I need and how do I input it into QGIS to get ...
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1answer
422 views

Efficiently generate Voronoi layers in qgis via Python

The following python commands both appear to function when called in qgis 2.6 to generate Voronoi diagrams: processing.runalg("qgis:voronoipolygons", pointLayer, 1, None) processing.runalg("grass:v....
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1answer
158 views

Thiessen Polygon Total Area Calculations Model Builder/Python Code

I am attempting to create a tool using Model Builder (and Python code) for calculating the average annual precipitation of a study area using the Thiessen Polygon Method. My model runs good other than ...
0
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1answer
88 views

Thiessen Ploygon Bifurcated Areas Calculations

I have a SewerGEMS network of a sewerage scheme for a town. The town is divided into 17 wards having different population densities in (Population/Hectare). There is an AutoCAD drawing showing the ...
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222 views

Calculations of Thiessen Polygon Bifurcated Areas

I have got a SewerGEMS network of a Sewerage Scheme for a Town. The Town is divided into 17 Wards having different Population Densities in (Population/Hectare). There is a AutoCAD drawing showing the ...
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3answers
428 views

How to count the sides or edges of a polygon?

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 ...
11
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1answer
2k views

How to use ST_DelaunayTriangles to construct a Voronoi diagram?

With PostGIS 2.1+ we can use ST_DelaunayTriangles() to generate a Delaunay triangulation, that is a dual graph of its Voronoi diagram, and, in theory, they have an exact and reversible conversion. ...
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1answer
1k views

Extracting centerline of a Complex-Polygon in PostGIS/Python

Any idea how to extract the centerline of the following polygon (Fig1) using PostGIS functions or Python modules? I was trying Voronoi Function but thats not helpful for this kind of shape. I want ...
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2answers
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What is the difference between Create Thiessen Polygons tool (ArcGIS) and Voronoi Polygons tool (QGIS)?

Is Thiessen polygons the same thing as Voronoi polygons? I am using ArcMap 10 and also QGIS 2.4 and I would like please to know the exact difference (If any) between the two methods.
3
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1answer
95 views

What is the correct cartographic projection to calculate a Voronoi tesselation?

I have a set of points with known geographic coordinates. I would like to compute a Voronoi tesselation from these points in order to obtain areas of influence. The geometrical area of each Voronoi ...
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4answers
1k views

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, ...
1
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1answer
204 views

Thiessen polygons of sub-districts to lie within district boundaries [duplicate]

I'm using ArcGIS 10.1 and am fairly new to it. I have the latitude and longitude of sub-districts, and wish to create Thiessen polygons of these sub-districts. I also have shapefiles for districts (...
2
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0answers
71 views

Iterative point feature removal based on Thiessen polygon values

The background is: I have point feature class and Thiessen polygons created based on it. I wanted to know for each point Thiessen polygon area value, so I have calculated Thiessen polygon area value ...