dbledensitymap: Double Kernel density estimates and map

In tibo31/GeoXp: Interactive Exploratory Spatial Data Analysis

Double Kernel density estimates and map

Description

The function dbledensitymap plots two kernel density estimates from 2 variables included in names.var computed with bkde, and a map with sites of coordinates sf.obj. Each site is associated to a value of names.var[1] and names.var[2] and the two windows are interactive.

Usage

dbledensitymap(sf.obj, names.var, kernel = "triweight", 
  criteria = NULL, carte = NULL, identify = NULL,
  cex.lab = 0.8, pch = 16, col = c("grey", "lightblue3"), xlab = c("", ""), 
  ylab = "", axes = FALSE, lablong = "", lablat = "")

Arguments

sf.obj	object of class sf
names.var	a vector of character of size 2; attribute names or column numbers in attribute table
kernel	Smoothing kernel (see help(bkde) for list of options)
criteria	a vector of boolean of size the number of spatial units, which permit to represent preselected sites with a cross, using the tcltk window
carte	matrix with 2 columns for drawing spatial polygonal contours : x and y coordinates of the vertices of the polygon
identify	if not NULL, the name of the variable for identifying observations on the map
cex.lab	character size of label
pch	16 by default, symbol for selected points
col	c("grey","lightblue3") by default, color of the two density curves
xlab	a list of title for the two x-axis graphics
ylab	a list of title for the two y-axis graphics
axes	a boolean with TRUE for drawing axes on the map
lablong	name of the x-axis that will be printed on the map
lablat	name of the y-axis that will be printed on the map

Details

The user can choose an interval on the density curve by mouse clicking on the lower and upper boundaries of the interval or by giving directly these values. The selected sites are then represented on the map in red. A selection by ‘points’ or ‘polygon’ on the map results in the drawing of the density of the corresponding sub-distribution on the density plot. Finally, the user can modify the bandwith parameter with a cursor in the tk window (parameter \alpha). \alpha is the smoothing parameter for the kernel smooth : it represents the mean percentage of sample points involved in the local averaging (example : \alpha=20 means that on average, n \times 0.2 points are in any interval of length 2h where h is the usual bandwidth).

Value

In the case where user click on save results button, a vector of integer is created as a global variable in last.select object. It corresponds to the number of spatial units selected just before leaving the Tk window.

Author(s)

Thomas-Agnan C., Aragon Y., Ruiz-Gazen A., Laurent T., Robidou L.

References

Thibault Laurent, Anne Ruiz-Gazen, Christine Thomas-Agnan (2012), GeoXp: An R Package for Exploratory Spatial Data Analysis. Journal of Statistical Software, 47(2), 1-23.

Roger S.Bivand, Edzer J.Pebesma, Virgilio Gomez-Rubio (2009), Applied Spatial Data Analysis with R, Springer.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. New York: Springer.

Wand M.P. et Jones M.C. (1995), Kernel Smoothing, Chapman \& Hall.

See Also

histomap, histobarmap, scattermap, densitymap

Examples

#########
# data auckland
require(sf)
auckland <- st_read(system.file("shapes/auckland.shp", package="spData")[1])

dbledensitymap(auckland, c("M77_85", "Und5_81"), xlab = c("M77_85", "Und5_81"),
  criteria = (auckland$M77_85 > mean(auckland$M77_85)))

## Not run:  
# data eire
require(sf)
eire <- st_read(system.file("shapes/eire.shp", package="spData")[1])

dbledensitymap(eire, c("A", "towns"), kernel = "normal",
  xlab = c("Individuals rate of blood type A", 
  "Surface urbaine"), identify = TRUE)

## End(Not run)

tibo31/GeoXp documentation built on April 8, 2023, 7:50 a.m.