Questions tagged [spatial-data]

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13 votes
5 answers
1k views

Repeated nearest neighbor calculation for millions of data points too slow

I have a dataset running into millions of data points in 3D. For the calculation I am doing, I need to calculate neighbor (range search) to each data point in a radius, try to fit a function, ...
Kaustubh Kaluskar's user avatar
5 votes
2 answers
3k views

Algorithms to extract trajectory lines out of 3D point clouds

I am looking for different approaches to extract 3D polylines out of Point Clouds. We are able to create these point clouds out of different data sources of real world surveys (LIDAR, RADAR, etc...) ...
Jürgen Zornig's user avatar
4 votes
1 answer
67 views

What statistical method should be used for spatial correlation between images?

I am working on analyzing a data set and I was wondering what would be the most statistically valid method of demonstrating that there is a strong spatial correlation between images. I have a data ...
Wandering Sophist's user avatar
3 votes
1 answer
1k views

Nearest Neighbors in radius via Z-order order curve?

Given a $M\times M\times M$ 3D cube grid $C$, how can I map the 3D grid-coordinates to 1D coordinates such that every cell's nearest neighbors can be represented by a continuous range of corresponding ...
sarasvati's user avatar
  • 185
2 votes
1 answer
87 views

Geographic distance between two regions

I am currently trying to calculate the geographic distance between two regions as I want to correlate it with their similarity of another aspect (e.g., similarity in word usage). Currently, I have ...
fsociety's user avatar
  • 151
2 votes
2 answers
948 views

Ideas on how to search nearby geospatial data fast

I am looking at a very simple problem, but can't quite find the best solution. I need to accept a lat/lon coordinate and based on that coordinate find all the points within roughly ~1km (accuracy is ...
user2924127's user avatar
1 vote
0 answers
48 views

Interpolate location based on triangular sensor array

There are 3 sensors (A, B, C) on a plane, located in the corners of a (known) equilateral triangle. I want to calculate the (2D) location of an object (X) inside that triangle. One sensor returns one ...
Prima's user avatar
  • 11
1 vote
0 answers
225 views

Use of Morton Key to reduce number of grid points

I asked a question on Stack Overflow Performance Issue with VP Trees and Nearest Neighborsand I was not satisfied with the answer and so I thought I would reword my question for this site and post ...
user avatar
1 vote
0 answers
62 views

Algorithm to explore a 3D scalar potential

I have to write an algorithm/code to reconstruct an unknown 3D scalar potential $ V(\mathbf{r})$ up to a specified threshold $E_c$ (assume that the potential is monotonic) The problem has the ...
Pie86's user avatar
  • 111
1 vote
0 answers
366 views

Practical implementation of spatial binning for rectangular range queries

I have a bunch of polygons and a coarse uniform grid. I want to implement two different range queries, for a rectangle aligned with the uniform grid: Does the rectangle intersect with any polygon at ...
Thomas Klimpel's user avatar
0 votes
0 answers
24 views

Sampling from a very high dimensional Gaussian with covariance in block form

I'm interested in sampling from a Gaussian with zero-mean and covariance given by: $$ \Sigma = \begin{bmatrix} \Sigma_{11} & \Sigma_{12} & \cdots &\Sigma_{1,100}\\ \Sigma_{21} & \...
WeakLearner's user avatar