GRASS GIS manual: r.pi.enn

NAME

r.pi.enn - Analysis of n-th Euclidean Nearest Neighbor distance.

KEYWORDS

raster

SYNOPSIS

r.pi.enn
r.pi.enn help
r.pi.enn [-aq] input=name output=name keyval=integer method=string[,string,...] number=num[-num][,num[-num],...] statmethod=string [dmout=string] [adj_matrix=string] [title="phrase"] [--overwrite] [--verbose] [--quiet]

Flags:

-a: Set for 8 cell-neighbors. 4 cell-neighbors are default
-q: Run quietly
--overwrite: Allow output files to overwrite existing files
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

input=name: Name of input raster map
output=name: Name for output raster map
keyval=integer: Key value
method=string[,string,...]: Operation to perform on fragments; Options: distance,path_distance,area,perimeter,shapeindex
number=num[-num][,num[-num],...]: Number of nearest neighbors to analyse
statmethod=string: Statistical method to perform on the values; Options: average,variance,standard deviation,value,sum
dmout=string: Output name for distance matrix and id-map (performed if not empty)
adj_matrix=string: Output name for adjacency matrix (performed if not empty)
title="phrase": Title for resultant raster map

DESCRIPTION

r.pi.enn computes the euclidean distance between patches (1-n NN). Analysis of n-th euclidean nearest neighbour distance.

NOTES

The user must specify the names of the raster map layers to be used for input and output, the keyval the method (e.g. distance, area) and statmethod used (i.e., average).

Within r.pi.enn the following setting have to be set:

keyval setting:

The keyval operator determines which category value is taken for the Patch Index analysis.

Method setting:

The method operators determine what measure is applied on the nth NN.

Distance

The Average computes the average distance of the n NN.

Path distance

The path_distance computes the actual distance to the n NN.

Area

The area computes the area of the n NN.

Perimeter

The perimeter computes the perimeter of the n NN.

SHAPE Index

The shapeindex computes the SHAPE Index of the n NN.

Statmethod setting:

The statmethod operators determine what statistic measure is applied on the nth NN.

Average

The Average computes the average distance of the n NN.

Variance

The Variance computes the variance of the distance of the n NN.

Std. Dev.

The Std. Dev computes the std. dev. of the distance of the n NN.

Number:

The keyval operator determines which or how many Nearest Neighbour are analysed. 1,2,5 will analyse the 1, 2 and 5th Nearest Neigbour. 1-10 will analyse the 1, 2, 3, ... 10th Nearest Neighbour. 0 will analyse all Nearest Neighbours.

Distancematrix:

The dmout operator is optional and determines if a distance matrix is written (first NN only). 1,2,5 will analyse the 1, 2 and 5th Nearest Neigbour. 1-10 will analyse the 1, 2, 3, ... 10th Nearest Neighbour. 0 will analyse all Nearest Neighbours.

EXAMPLE

An example for the North Carolina sample dataset:

r.pi.enn input=landclass96 output=dist1.c5 keyval=5 method=distance number=1 statmethod=average 
# -> gives a map of patches (all of category of 5) with the average distance to their first NN

r.pi.enn input=landclass96 output=dist10.c5 keyval=5 method=distance number=10 statmethod=average 
# -> gives a map of patches (all of category of 5) with the average distance to their first-10th NN

r.pi.enn input=landclass96 output=dist1.5.10,c5 keyval=5 method=distance number=1,5,10 statmethod=average 
# -> gives a map of patches (all of category of 5) with the average distance to their first, first-to-fifth and first-to-10th NN

r.pi.enn input=landclass96 output=dist10b.c5 keyval=5 method=path_distance number=10 statmethod=average 
# -> gives a map of patches (all of category of 5) with the actual distance to the 10th NN

AUTHORS

Programming: Elshad Shirinov
Scientific concept: Dr. Martin Wegmann
Department of Remote Sensing
Remote Sensing and Biodiversity Unit
University of Wuerzburg, Germany

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