GeoXp (version 1.6.2)

histomap: Interactive Histogram and map

Description

The function histomap() draws a histogram of a given variable name.var and a map with sites of coordinates coordinates(sp.obj). Each site is associated to a value of name.var and there is interactivity between the two windows.

Usage

histomap(sp.obj, name.var, nbcol=10, type = c("count","percent", "density"),
names.attr=names(sp.obj), criteria=NULL, carte=NULL, identify=FALSE, cex.lab=0.8, 
pch=16, col="lightblue3", xlab="", ylab="", axes=FALSE, lablong="", lablat="")

Arguments

sp.obj

object of class extending Spatial-class

name.var

a character; attribute name or column number in attribute table

nbcol

number of cells for histogram (10 by default)

type

Character string indicating type of histogram to be drawn. "percent" and "count" give relative frequency and frequency histograms, "density" produces a density scale histogram.

names.attr

names to use in panel (if different from the names of variable used in sp.obj)

criteria

a vector of size n of boolean 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 FALSE, identify plotted objects (currently only working for points plots). Labels for identification are the row.names of the attribute table row.names(as.data.frame(sp.obj)).

cex.lab

character size of label

pch

16 by default, symbol for selected points

col

"lightblue3" by default, color of bars on the histogram

xlab

a title for the graphic x-axis

ylab

a title for the graphic y-axis

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

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.

Details

Sites selected by a bar on the histogram are represented on the map in red and the values of sites selected on the map by `points' or `polygon' are represented in red as a sub-histogram on the histogram.

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.

See Also

histomap, histobarmap, scattermap, densitymap

Examples

######
# data oldcol
require("maptools")
example(columbus)

# columbus is included in the Spatial-Class object
# a very simple use of histomap :
histomap(columbus,"CRIME")

######
# data on price indices of real estate in France
data(immob)

# immob is a data.frame object. We have to create
# a Spatial object, by using first the longitude and latitude
# to create Spatial Points object ...
immob.sp = SpatialPoints(cbind(immob$longitude,immob$latitude))
# ... and then by integrating other variables to create SpatialPointsDataFrame
immob.spdf = SpatialPointsDataFrame(immob.sp, immob)
# we just give names to the spatial units...
row.names(immob.spdf)<-immob$Nom
# For more details, see vignette('sp', package="sp")

# optional : we add some contours that don't correspond to the spatial unit
# but are nice for mapping
midiP <- readShapePoly(system.file("shapes/region.shp", package="GeoXp")[1])
cont_midiP<-spdf2list(midiP[-c(22,23),])$poly

# A basic call of histomap function
histomap(immob.spdf,"prix.vente", carte= cont_midiP, identify=TRUE, cex.lab=0.6)

# ... with all options
histomap(immob.spdf,7, nbcol=15, type = "percent",
names.attr=names(immob), criteria=immob$rentabilite>5, carte=cont_midiP,
identify=TRUE, cex.lab=0.5, pch=12, col="pink",
xlab="variation price", ylab="percent", axes=TRUE, lablong="x",
lablat="y")