echelon: Echelon analysis for spatial data

In echelon: The Echelon Analysis and the Detection of Spatial Clusters using Echelon Scan Method

Description

echelon divides study area into structural entities consisting of peaks or foundations, say 'echelons', based on neighbor information, and draw its dendrogram.

Usage

echelon(x, nb, dendrogram = TRUE, name = NULL,
      main = NULL, ylab = NULL, yaxes = TRUE, ylim = NULL,
      xaxes = FALSE, xdper = c(0, 1), dmai = NULL,
      col = 1, lwd = 1, symbols = 4, cex.symbols = 1, col.symbols = 4,
      ens = TRUE, adj.ens = 1, cex.ens = 0.8, col.ens = 1,
      profiles = FALSE)

Arguments

x	A numeric vector of data values.
nb	Neighbor information data. An object of class nb or a weights matrix.
name	The region names. if NULL, it is assigned 1:length(x).
dendrogram	Logical. if TRUE, draw an echelon dendrogram.
main	Related to dendrogram drawing. An overall title for the dendrogram.
ylab	Related to dendrogram drawing. A title for the y axis.
yaxes	Related to dendrogram drawing. Logical. if TRUE, draw the y axis.
ylim	Related to dendrogram drawing. A scale of y axis given by c(min, max).
xaxes	Related to dendrogram drawing. Logical. if TRUE, draw the x axis.
xdper	Related to dendrogram drawing. A display percentage of x axis. The full display percentage is given in [0, 1].
dmai	Related to dendrogram drawing. A numerical vector of the form c(bottom, left, top, right) which gives the margin size specified in inches. Default is set to c(0.4, 0.8, 0.3, 0.01).
col	Related to dendrogram drawing. A line color of the dendrogram.
lwd	Related to dendrogram drawing. A line width of the dendrogram.
symbols	Related to dendrogram drawing. Either an integer specifying a symbol or a single character. If integer, it is synonymous with pch in par.
cex.symbols	Related to dendrogram drawing. A magnification to be used for the plotting symbols.
col.symbols	Related to dendrogram drawing. A color to be used for the plotting symbols.
ens	Related to dendrogram drawing. Logical. if TRUE, draw the labels of echelon numbers.
adj.ens	Related to dendrogram drawing. Adjustment of the labels of the echelon numbers.(see the help for text("adj")).
cex.ens	Related to dendrogram drawing. A magnification to be used for the labels of echelon numbers.
col.ens	Related to dendrogram drawing. A color to be used for the labels of echelon numbers.
profiles	Logical. if TRUE, return the result of echelon profiles. (See [2] for the details of echelon profiles)

Value

The function echelon returns an object of class echelon. An object of class echelon contains the following components:

Table	Summary of each echelon.
Echelons	Regions that composes each echelon.

Note

If there are NA in x, then that is set the minimum value of x.

Sf::st_read and spdep::poly2nb are useful for creating the object specified in the argument nb.

Author(s)

Fumio Ishioka

References

[1] Myers, W.L., Patil, G.P. and Joly, K. (1997). Echelon approach to areas of concern in synoptic regional monitoring. Environmental and Ecological Statistics, 4, 131–152.

[2] Kurihara, K., Myers, W.L. and Patil, G.P. (2000) Echelon analysis of the relationship between population and land cover patter based on remote sensing data. Community ecology, 1, 103–122.

See Also

echepoi and echebin for cluster detection based on echelons.

Examples

##Echelon analysis for one-dimensional data with 25 regions
#A weights matrix
one.nb <- matrix(0,25,25)
one.nb[1,2] <- 1
for(i in 2:24) one.nb[i,c(i-1,i+1)] <- c(1,1)
one.nb[25,24] <- 1

#25 random values
one.dat <- runif(25) * 10

#Echelon analysis
echelon(x = one.dat, nb = one.nb)


##Echelon analysis for SIDS data for North Carolina
#Mortality rate per 1,000 live births from 1974 to 1984
library(spData)
data("nc.sids")
SIDS.cas <- nc.sids$SID74 + nc.sids$SID79
SIDS.pop <- nc.sids$BIR74 + nc.sids$BIR79
SIDS.rate <- SIDS.cas * 1000 / SIDS.pop

#Echelon analysis
SIDS.echelon <- echelon(x = SIDS.rate, nb = ncCR85.nb, name = row.names(nc.sids),
  symbols = 12, cex.symbols = 1.5, ens = FALSE)
text(SIDS.echelon$coord, labels = SIDS.echelon$regions.name,
  adj = -0.1, cex = 0.7)

#Echelon Profiles
echelon(x = SIDS.rate, nb = ncCR85.nb, profiles = TRUE)

echelon documentation built on Jan. 11, 2020, 9:21 a.m.