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Questions tagged [concave-hull]

56 questions
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Homemade Python Concave Hull but why a bit off

I could not find a fast and reliable concave hull and implemented my own (though a bit heterodox). It is fast and does the job (there is even an adjustment parameter) but it is a bit off. I got confuse with r,c vs x,y a couple of time maybe it has…
Uğur Dinç
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Is there any command which will give me a alpha shape based on multipoint geometry?

Good Day Everyone, I am having the clustered geodata which has a multipoint as a geometry. I am able to create convex hulls, using geopanda's method convex_hull. But somehow I was not able to find a similar command for creating an alpha shape. Or…
Avto Abashishvili
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How to compute the total concave surface area on a 3D binary mask in Matlab?

I have a 3D binary mask (from a Dicom image) with one object in it. I want to calculate the total concave surface area and also the total convex surface area of the object in it. For the total convex surface area, I have used this link, which its…
Ellie
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Point cloud library missing header files after vcpkg installation

I am quite a beginner to programming so I am sorry for my basic question. I installed PCL 11.1 via vcpkg manager a few weeks ago and now I have realized I am missing some header files. In particular pcl/surface/concave_hull.h and some more…
JanH
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Image Processing: concaveHull to find defects of an image

I've been trying to identify a method to calculate defects (line roughness) and convexHull is the only real method I've found. This method does exactly what I want with the exception that it doesn't follow the curvature of the lines at all. Below is…
Cameron Greenwalt
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3D alpha shape for finding the boundary of points cloud in python

I'm trying to find the surface of points cloud using the 3D alpha shape algorithm. When I calculate the circumradius, the determinant a is equal to zero, leading to the error 'divide by zero encountered in double_scalars'. What should i do with it?…
user14416719
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Get multiple polygons for scattered data in R

I have point cloud data of an area (x,y,z coordinates) The plot of X and Y looks like: I am trying to get polygons of different clusters in this data. I tried the following: points <- df [,1:2] # x and y coordinates pts <- st_as_sf(points,…
Mansi
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Build constrained alpha shape of polygons

I have a quite specific task. I need to compute alpha shape of a set of points. (You can frolic with already implemented algorith there) The point is that I have predefined subsets of points (let's call them details) and I do not want their…
Sviatoslav Iakovlev
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Connecting a set of points to get a non-self-intersecting non-convex polygon

I have an unordered set of 2D points which represents the corners of a building. I need to connect them to get the outline of the building. The points were obtained by combining different polygons collected by different individuals. My idea is to…
Nikhil Jose
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Get alpha-shape (concave hull) of a set of points using Julia

I want to compute the alpha-shape (or even only the concave hull) of a set of points using Julia. In other questions they have solved this problem in python by using Delaunay tesselation Boundary enclosing a given set of points . This package in…
RM-
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Python - Complementary gear shape

I'm trying to find the complementary rotary "gear" shape to any input polygon shape. For example this polygon, is rotated around so that the complementary gear becomes apparent. Both shapes would be able to rotate without interferences. I'm having…
CyrielN
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How to get the correct Concave Hull using OpenTripPlanner API?

The following code does not give me the result I expected. I expect to have all the points as the nodes of the polygon and the polygon contains all the points. How to use the API correctly? Also if I set thresold less than 1, the program got into…
Paul Z Wu
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Identifying concave hull of points in higher dimension

I have a set of points(clusters) in higher dimension (30d to 100d). I need to identify concave hull of these points in an efficient manner. Is there a way to do get the exact concave hull or atleast approximate concave hull of these set of points?…
Mihir Shekhar
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Finding the concave hull of a set of points such that every point is in the boundary

So I am attempting to make complex polygons from a set of randomly generated vertices in 2D. I would like to allow concave polygons to exist, as well as to assure that every vertex in the set is included in the boundary (so the algorithm must be…
DeceitfulEcho
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How to find multiple concave & convex shapes in an image

The image attached is a mask of "walkable space" for a game, which is painted by the player, and so could be anything. I need to create colliders that prevent the player from walking on to the blue parts of the mask (water). The game itself is in 3D…
Dann
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