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Nearest neighbors of a of 3D points

3 messages · Eric Leroy, David L Carlson

Original
Eric Leroy
# 
Hi,

I have a text file that contains the 3D coordinates of points and I want 
to plot the histogram of the nearest neighbors distance. I can import 
the xyz coordinates in R and each value x, y, z is stored in a numerical 
array. I discovered the nndist.pp3 function from the spatstat package 
that seems to do what I want. My problem is to create a pp3 object from 
the xyz values that I have.

Do you know how to do that ?

Best regards,
David L Carlson
# 
What have you tried so far? Have you installed the spatstat package and read the manual page for pp3 objects? The website spatstat.org has additional support including a quick reference guide. There are always multiple ways to do something in R, but without more details it is hard to be specific. Nearest neighbor distances are also provided in several other packages, e.g. packages FNN, distances, and RANN.

----------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77843-4352

-----Original Message-----
From: R-help <r-help-bounces at r-project.org> On Behalf Of Eric Leroy
Sent: Wednesday, February 6, 2019 2:37 AM
To: r-help at r-project.org
Subject: [R] Nearest neighbors of a of 3D points

Hi,

I have a text file that contains the 3D coordinates of points and I want 
to plot the histogram of the nearest neighbors distance. I can import 
the xyz coordinates in R and each value x, y, z is stored in a numerical 
array. I discovered the nndist.pp3 function from the spatstat package 
that seems to do what I want. My problem is to create a pp3 object from 
the xyz values that I have.

Do you know how to do that ?

Best regards,
Eric Leroy
# 
I tried the spatstat package. In the meanwhile, I think that I found the 
solution: with the pp3 command, I was able to create a pp3 object that 
is recognized by nndist.

I will give a look at the other packages you mentioned seeing what are 
the differences.

Anyway, thank you for your answer.

*Eric Leroy*

/Responsable de la plateforme microscopie ?lectronique/

ICMPE - UMR 7182 - CNRS - UPEC

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94320 Thiais

T?l : 01.49.78.12.09

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courriel : eric.leroy at icmpe.cnrs.fr <mailto:eric.leroy at icmpe.cnrs.fr>

Page Web : : http://www.icmpe.cnrs.fr

Le 06/02/2019 ? 17:06, David L Carlson a ?crit?: