13,283 questions
Advice
0
votes
5
replies
179
views
Drawing geometric diagrams in R, ggplot
To illustrate the ideas behind discriminant analysis, I created the image below containing a scatterplot with two groups and a plot of the densities of the scores, LD1 on the discriminant function.
...
- 4,083
-4
votes
1
answer
76
views
How to compute an optimal enclosing segment of a circle from a 2D point set?
I am looking for some advice on how to fit a circular segment to a set of 2D points. My dataset looks like this: 2d data to fit segment to
For clarity, my definition of an "optimal" segment ...
2
votes
1
answer
124
views
Calculating a light volume that comes in through a window
I have a room that is a box. There is a single rectangular window on one of the walls of the room. A directional light source is shining into the room through the window. The light source has a ...
- 133
1
vote
1
answer
146
views
Turn a convexhull defined by a list of 3D point coordinates into a 0-1 binary mask
I have a convexHull given by a list of 3d point coordinate generated by scipy.spatial.ConvexHull. Now the question is, I want to turn this convexhull defined by the list of vertices into a 0-1 binary ...
- 11
3
votes
0
answers
76
views
Efficient function to check if there is a convex k-gon in given n points in 2D?
Suppose I am given n points in the plane, (x_1, y_1), ... , (x_n, y_n). I want to check if there is a subset of k points from these n that make a convex k-gon.
For instance, say I am given 25 points ...
1
vote
0
answers
89
views
Shape registration using PCA and GPA not aligning
I am currently working on a statistical shape model/active shape model to make it fit a vertebra. But for some reason it is not working and I have been trying to fit it for some time.
First I tried ...
- 11
0
votes
0
answers
107
views
Gmsh: “Wrong topology of boundary mesh for parametrization” or endless “Partitioning face…” warnings when creating geometry from STL
I’m trying to turn a 3D STL surface (exported from ImageJ/Fiji segmentation) into a volume mesh in Gmsh using the typical workflow given by the official tutorial (t13). I’m running this with the Gmsh ...
- 1
0
votes
1
answer
98
views
Detect if circle crossing arc, Lua
How can I detect whether a circle intersects or crosses a given arc segment?
The arc is defined by a center, radius, start angle (angle1), and end angle (angle2).
How to detect that arc AB has ...
- 596
4
votes
1
answer
180
views
Calculate rotation of a point around another point on earth (or sphere)
Essentially what I'm trying to do is moving a point relative to two different scales.
The reason is to edit values in a database of a 3d party application.
So basically I want to relocate the red ...
- 43
0
votes
1
answer
165
views
Finding a centerline of a contour?
I want to draw the centerline of a contour I made for the cable in the middle of the video I linked at the bottom. I also want to document the points of the centerline drawn in an array. How do I do ...
- 11
0
votes
0
answers
43
views
NetTopologySuite issue
Has anyone encountered this error when working with NetTopologySuite:
System.InvalidCastException: Reading as 'NetTopologySuite.Geometries.Geometry' is not supported for fields having DataTypeName '...
0
votes
0
answers
140
views
Getting ORA-00942 error when running Insert Into
I am trying to insert data from a couple different tables in 2 different databases using database links. If I run the select query on it's own, it runs without error and returns the expected results. ...
- 21
1
vote
1
answer
60
views
Inferring the drawing direction of a rotation+reflection matrix applied to a canvas
I am trying to extract the drawing direction of a DOMMatrix with reflection and rotation applied (using rotate, scale). What I want to know is whether it will draw upwards vs. downwards or leftwards ...
- 171
2
votes
1
answer
100
views
Calling a function that returns a vector by value in place and iterating over elements causes first value to be garbage
I have been trying to integrate boost geometry into a project but run into an issue when I return a polygon geometry from my custom class. The following is a minimal example that reproduces what I am ...
- 21
0
votes
1
answer
54
views
I want to reduce cost related to a specific geospatial filtering
This is the following query :
SELECT
id,
x,
date_range_start
FROM table_a
WHERE ST_DWITHIN(point, shape_polygon, 30)
After running some tests, i can confidently say that WHERE ST_DWITHIN(...
- 1
8
votes
2
answers
263
views
How can I find the largest axis-aligned rectangle of a given aspect ratio that can fit inside a rotated rectangle?
Given a rotated rectangle, how can I find the largest axis-aligned rectangle of a given aspect ratio that can fit within the original rectangle? For example, I'd want to find the largest rectangle of ...
- 1,490
0
votes
1
answer
110
views
How to create an apache iceberg table with geometry column?
from pyspark.sql import SparkSession
from sedona.spark import SedonaContext
from pyspark.sql.functions import expr
spark = (
SparkSession.builder
.appName("SedonaIcebergApp")
...
- 1
18
votes
3
answers
191
views
Trilateration where we have heading instead of distance to the known points
I'm trying to do a form of trilateration, where the distances between the point of interest (POI) and the anchor points are not given, but instead the heading observed from the POI to each of the ...
- 389
3
votes
2
answers
173
views
How can I calculate the number of local maxima in a 3D matrix in R?
I am currently working on a number of animal teeth stored as surface meshes in R. Some of the variables I am looking at may be influenced by the number of cusps on the tooth and I would like to try ...
- 416
0
votes
1
answer
46
views
Split the large facet in the geojson file into multiple small facets
I have a geojson file that needs to iterate over all the polygons in all the features, but some of them are very large, making it slow to perform certain tasks, and I would like to split them into ...
- 98
0
votes
0
answers
29
views
Scaling centered objects between two page layouts with differing margins and gutters
I have a set of graphical objects whose positions are defined relative to the center of a two-page spread. I need to convert them from one page layout to another, where each layout may have different:
...
0
votes
1
answer
59
views
Projecting Depth of Adjacent Pixel based on Normal
I'm working on a screen-space outline effect for a low-res, cartoony game idea. I'm very new to HLSL programming and fullscreen Shader Graphs, but by looking at tutorials, I've mostly gotten the depth-...
- 39
0
votes
0
answers
63
views
Android Java Plot Marker on Google Map with Geometry Point
How will I plot a marker on Google Map with my geometry points? Here is the sample geometry points POINT Z (642823.3317 937067.5592999998 0).
I added a JTS dependencies which is org.locationtech.jts. ...
- 176
3
votes
1
answer
116
views
How to shorten the length of a .Net C# System.Windows.Shapes.Line at runtime?
Before I illustrate my question with words please imagine a 2D square on a screen. In the center of that square is an archer with a bow.
In every corner of the square is a target. When a point on a ...
- 333
0
votes
0
answers
47
views
"Convert an oracledb.Lob into a geometry type compatible with GeoPandas."
I have a DataFrame where the geometry data was imported from an Oracle database. It looks like this:
df_wkt.head()
The output is:
FID WKT_GEOM
0 214213 CURVEPOLYGON (COMPOUNDCURVE ((...
- 11