neighbourmap: Neighbour plot and map

In tibo31/GeoXp: Interactive Exploratory Spatial Data Analysis

Neighbour plot and map

Description

The function neighbourmap() identifies spatial outliers by comparing a variable value for a particular site with these of its neighbouring sites. It draws a scatterplot of the values of the variable at neighbouring sites for a neighbourhood structure given by a binary weight matrix W and links this scatterplot with a map.

Usage

neighbourmap(sf.obj, name.var, nb.obj, lin.reg = TRUE, 
  criteria = NULL, carte = NULL, identify = NULL, 
  cex.lab = 0.8, pch = 16, col = "lightblue3", xlab = "", ylab = "", 
  axes = FALSE, lablong = "", lablat = "")

Arguments

sf.obj	object of class sf
name.var	a character; attribute name or column number in attribute table
nb.obj	object of class nb
lin.reg	If TRUE, drawing the linear curve y=x
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	"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

Details

For a selected site j on the map, are represented on the map its neighbors, and on the graph, on the x-axis the value of var for this site, and in y-axis, the values of var for the neighbouring sites of j. For a selected point on the graph, the corresponding pair of sites is represented on the map with a link.

Value

In the case where user click on save results button, a matrix of integer is created as a global variable in last.select object. It corresponds to the numbers of spatial unit corresponding to couple of sites selected just before leaving the Tk window.

Note

When user selects sites on the graph or on the map, he cannot add a selection by using the other graphic.

Author(s)

Aragon Y., Thomas-Agnan C., 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.

See Also

moranplotmap,makeneighborsw,normw,nonormmoran

Examples

###
# columbus
require("sf")
columbus <- sf::st_read(system.file("shapes/columbus.shp", package="spData")[1])
col.gal.nb <- spdep::read.gal(system.file("weights/columbus.gal", package="spData")[1])

# example of use of neighbourmap
neighbourmap(columbus, "CRIME", col.gal.nb,
  criteria = (columbus$CRIME > mean(columbus$CRIME)))

###
# data immob
# data on price indices of real estate in France
data(immob, package = "GeoXp")

# immob is a data.frame object. We have to create
# a Spatial object, by using first the longitude and latitude
require(sf)
immob.sf <- st_as_sf(immob, coords = c("longitude", "latitude"))
# optional : we add some contours that don't correspond to the spatial unit
# but are nice for mapping
midiP <- st_read(system.file("shapes/region.shp", package="GeoXp")[1])

# A spatial weight matrix based on triangulation Delaunay
W.nb <- spdep::tri2nb(cbind(immob$longitude, immob$latitude))

# example of use of neighbourmap
neighbourmap(immob.sf, "prix.vente", W.nb, identify = "Nom", cex.lab = 0.5,
   carte = midiP)

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