ThomasPointProcess
✖
ThomasPointProcess
represents a Thomas cluster point process with density μ, cluster mean λ and scale parameter σ in .
Details

- ThomasPointProcess models clustered point configurations with centers uniformly distributed over space and cluster points isotropically distributed with a light-tail radial distribution.
-
- Typical uses include areas like cosmology, where the clusters are galaxy clusters, or plant ecology.
- The cluster centers are placed according to PoissonPointProcess with density μ.
- The point count of a cluster is distributed according to PoissonDistribution with mean λ.
- The cluster points in each cluster are isotropically distributed with the radial distribution NormalDistribution[0,σ] centered at a cluster center.
-
- ThomasPointProcess allows μ, λ and σ to be any positive real numbers, and d to be any positive integer.
- The following settings can be used for PointProcessEstimator for estimating ThomasPointProcess:
-
"FindClusters" use FindClusters function "MethodOfMoments" use a homogeneity measure to estimate the parameters - ThomasPointProcess can be used with such functions as RipleyK, PointCountDistribution and RandomPointConfiguration.
Examples
open allclose allBasic Examples (4)Summary of the most common use cases
Sample from a Thomas point process over a unit disk:

https://wolfram.com/xid/0d4jv629oujvur26-4mqsf


https://wolfram.com/xid/0d4jv629oujvur26-d381by

Sample from a Thomas point process over a unit ball:

https://wolfram.com/xid/0d4jv629oujvur26-dgk7lg


https://wolfram.com/xid/0d4jv629oujvur26-svdcv0

Sample from a Thomas point process over a geo region:

https://wolfram.com/xid/0d4jv629oujvur26-uf2aio

https://wolfram.com/xid/0d4jv629oujvur26-uc5jvc


https://wolfram.com/xid/0d4jv629oujvur26-uc869u

Pair correlation function of a Thomas point process:

https://wolfram.com/xid/0d4jv629oujvur26-0puauw

Visualize the function with given parameter values:

https://wolfram.com/xid/0d4jv629oujvur26-daj61m

Scope (2)Survey of the scope of standard use cases
Sample from any valid RegionQ, whose RegionEmbeddingDimension is equal to its RegionDimension:

https://wolfram.com/xid/0d4jv629oujvur26-qxrhco

https://wolfram.com/xid/0d4jv629oujvur26-pacet0


https://wolfram.com/xid/0d4jv629oujvur26-ydq337


https://wolfram.com/xid/0d4jv629oujvur26-h8cla8

Simulate a point configuration from a Thomas point process:

https://wolfram.com/xid/0d4jv629oujvur26-8c7zax

https://wolfram.com/xid/0d4jv629oujvur26-9g5xhe

Use the "FindClusters" method to estimated a point process model:

https://wolfram.com/xid/0d4jv629oujvur26-3o7emz

Compare Ripley's measure between the original process and the estimated model:

https://wolfram.com/xid/0d4jv629oujvur26-m5qyr2

Properties & Relations (5)Properties of the function, and connections to other functions
PointCountDistribution is known:

https://wolfram.com/xid/0d4jv629oujvur26-1vmg8n

https://wolfram.com/xid/0d4jv629oujvur26-69w4w


https://wolfram.com/xid/0d4jv629oujvur26-k29vdf


https://wolfram.com/xid/0d4jv629oujvur26-iw9fj7


https://wolfram.com/xid/0d4jv629oujvur26-rl0tf0
The probability density histogram:

https://wolfram.com/xid/0d4jv629oujvur26-57hv5g

Ripley's and Besag's
for a Thomas point process in 2D:

https://wolfram.com/xid/0d4jv629oujvur26-zht24f

https://wolfram.com/xid/0d4jv629oujvur26-1gisn


https://wolfram.com/xid/0d4jv629oujvur26-myijw0


https://wolfram.com/xid/0d4jv629oujvur26-26ar4l


https://wolfram.com/xid/0d4jv629oujvur26-5pj0tq

Ripley's of the Thomas point process is larger than for a Poisson point process:

https://wolfram.com/xid/0d4jv629oujvur26-zglflc

https://wolfram.com/xid/0d4jv629oujvur26-cp3zmu

https://wolfram.com/xid/0d4jv629oujvur26-7f0ncr


https://wolfram.com/xid/0d4jv629oujvur26-7jdja1

Besag's of the Thomas point process is greater than of the Poisson point process:

https://wolfram.com/xid/0d4jv629oujvur26-037cpr

https://wolfram.com/xid/0d4jv629oujvur26-kdnk7q

https://wolfram.com/xid/0d4jv629oujvur26-vk8oue


https://wolfram.com/xid/0d4jv629oujvur26-1avd72

The pair correlation function of a Thomas point process is greater than 1:

https://wolfram.com/xid/0d4jv629oujvur26-tlke7q

Compare to the homogeneous Poisson point process:

https://wolfram.com/xid/0d4jv629oujvur26-o75yfs

Wolfram Research (2020), ThomasPointProcess, Wolfram Language function, https://reference.wolfram.com/language/ref/ThomasPointProcess.html.
Text
Wolfram Research (2020), ThomasPointProcess, Wolfram Language function, https://reference.wolfram.com/language/ref/ThomasPointProcess.html.
Wolfram Research (2020), ThomasPointProcess, Wolfram Language function, https://reference.wolfram.com/language/ref/ThomasPointProcess.html.
CMS
Wolfram Language. 2020. "ThomasPointProcess." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ThomasPointProcess.html.
Wolfram Language. 2020. "ThomasPointProcess." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ThomasPointProcess.html.
APA
Wolfram Language. (2020). ThomasPointProcess. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ThomasPointProcess.html
Wolfram Language. (2020). ThomasPointProcess. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ThomasPointProcess.html
BibTeX
@misc{reference.wolfram_2025_thomaspointprocess, author="Wolfram Research", title="{ThomasPointProcess}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/ThomasPointProcess.html}", note=[Accessed: 27-April-2025
]}
BibLaTeX
@online{reference.wolfram_2025_thomaspointprocess, organization={Wolfram Research}, title={ThomasPointProcess}, year={2020}, url={https://reference.wolfram.com/language/ref/ThomasPointProcess.html}, note=[Accessed: 27-April-2025
]}