Questions tagged [delaunay]

A prefix to help define a type of mathematical transformation, such as Delaunay Triangulation, or Delaunay Tesselation

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Creating a 3D TIN or similar 3D Delaunay triangulation in R

Background: I have topographical datasets with height information as a starting point. The endgame is to create a dataset of triangulations which I can use to import into Parasolid to be used further ...
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Calculating delaunay triangulation with two diagonal lines using ArcGIS Desktop?

How do I obtain a line output similar to a delaunay triangulation but with two diagonal lines, from a point layer containing a regular-spaced point grid using ArcGIS Desktop? The current result is ...
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1answer
36 views

Arcs from a Delaunay Triagulation

I am trying to generate a Cost Distance table using Spatialite. I have several points in the table random_points for which I would like to compute the Delaunay triangulation and use the segments it ...
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Incomplete Delaunay triangulation unsing pyqgis3

I'm writing a small Qgis3 python plugin to convert polygon shapefiles to input files for a scientific model. I therefore need to split up the polygon geometries to more simple geometries with up to 4 ...
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1answer
89 views

Match SpatialPoints to Delaunay Triangles in R

I have 2 SpatialPointsDataFrame files. I compute the Delaunay Triangles from the first shapefile (shp1) as in the code below. Then I wish to assign each point from my second shapefile (shp2) to one of ...
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Apollonius Graphs (Delaunay Graphs of Disks) in sfcgal or PostGIS?

I was wondering if there is support for Delaunay Graphs of Disks (a.k.a. Apollonius Graphs) in PostGIS/sfcgal? A CGAL function seems to exist for this. But I can't seem to find it in the PostGIS ...
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0answers
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Polygons hull QGIS [duplicate]

I'm currently working with old french cadastre on QGIS, I've vectorised it and now I want to tile it. I've georeferenced it, but it's not sufficient for a great result. To improve the result, I would ...
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4answers
476 views

Minimum wall-thickness of a non convex polygon with holes

What is the most efficient way to find the minimal wall-thickness (value and location) of a complex, non convex polygon area including holes? See example of a polygon in blue, with the minimum wall-...
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1answer
749 views

St_delaunaytriangles polygon with holes

I'm using PostGIS to decompose a polygon with a few holes into triangles via st_delaunaytriangles. Unfortunately, it does not return the right result with holes, because the triangles being outputted ...
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4answers
813 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 ...
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1answer
58 views

Query Z at intersecting point locations from a MultiPolygonZ?

I create a MultiPolygonZ geometry with ST_DelaunayTriangles(). select st_setsrid( ST_CollectionExtract( ST_DelaunayTriangles( ST_GeomFromText('MULTIPOINT ...
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380 views

Constrained Delaunay Triangulations in PostGIS?

It is possible to make Constrained Delaunay triangulations in PostGIS (PostgreSQL)? I have a Polygon and I need to make internal triangulation like this: I tried to use ST_DelaunayTriangles but is ...
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606 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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57 views

Calculating a new attribute for a polygon based on its corners

i have a pointlayer with a real number as attribute named amount. I want to calculate and visualize the difference of amount between neighbourhood points. So first I made a delaunay triangulation ...
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1answer
168 views

How do I create line vectors with a new ID from points in QGIS?

I have a list of stations from which I would like to create a network of lines (the one created with the Delaunay triangulation would be fine) identified by a particular ID (for example, "AB" for the ...
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3answers
1k views

How to set up a threshold for Delaunay triangulation?

I've been working Delaunay triangulation on a set of random points inside a group of mostly linear areas (in fact, buffers around rivers). The problem is that while the triangulation works correctly ...
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Delaunay Triangulation on labeled data

I have a table with locations and labeled data and I need to apply Delaunay Triangulation on specific labeled rows. For example, I have some locations labeled as schools, hostels, gardens, ... and I ...
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1answer
294 views

Extracting coordinates of a triangulation from DEM data

I'm working on the succinct representation of planar graphs and now I'm trying to obtain some datasets to test my results. I saw that Delaunay triangulations of elevation data can be a good source of ...
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1answer
82 views

How to identify Sliver triangles in a TIN surface and count them? [closed]

Is it possible to count slivers in a TIN? I generated a Delaunay triangulation surface model and i want to know how many slivers the TIN has.
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148 views

Contours from delaunay triangles

I have generated a delaunay polygon file that represents terrain data. Is there a way I can produce contours from the polygon file? I know I can convert the polygon to an Esri TIN, and then produce ...