MTA (version 0.2.0)

tdev: Territorial Deviation

Description

Compute the deviation of each territorial unit as regards to an intermediate territorial level of reference.

Usage

tdev(x, var1, var2, type = "rel", key)

Arguments

x

a dataframe, an sf object or a SpatialPolygonsDataFrame including var1 and var2, and an aggregation key field (territorial belonging).

var1

name of the numerator variable in x.

var2

name of the denominator variable in x.

type

type of deviation; "rel" for relative deviation, "abs" for absolute deviation (see Details).

key

aggregation key field for measuring the deviation (intermediate territorial level).

Value

A vector is returned.

Details

The relative territorial deviation is the ratio between var1/var2 and var1/var2 at the aggregated level. Values greater than 100 indicate that the unit ratio is greater than the ratio at the aggregated level. Values lower than 100 indicate that the unit ratio is lower than the ratio of the aggregated level. The absolute territorial deviation is the amount of numerator that could be moved to obtain the ratio of the aggregated level on all belonging units.

Examples

# NOT RUN {
library(sf)
library(cartography)
# load data
data("GrandParisMetropole")

# compute absolute territorial deviation (EPT level)
com$tdevabs <- tdev(x = com, var1 = "INC", var2 = "TH", type = "abs", 
                    key = "EPT")
# compute relative territorial deviation (EPT level)
com$tdevrel <- tdev(x = com, var1 = "INC", var2 = "TH", type = "rel", 
                    key = "EPT")

# map deviations
# set graphical parameters
par(mar = c(0,0,1.2,0))
# set breaks
bks <- c(min(com$tdevrel),75,100,125,150,max(com$tdevrel))
# set color palette
cols <- carto.pal(pal1 = "blue.pal", n1 = 2,
                  pal2 = "wine.pal", n2 = 3)
# plot a choropleth map of the relative territorial deviation
choroLayer(x = com, var = "tdevrel",
           legend.pos = "topleft",
           breaks = bks, border = NA,
           legend.title.txt = "Relative Deviation\n(100 = territorial average)",
           col = cols)
# add symbols proportional to the absolute territorial deviation
com$sign <- ifelse(test = com$tdevabs < 0, yes = "negative", no = "positive")
propSymbolsTypoLayer(com, var = "tdevabs", var2 = "sign",
                     legend.var.pos = "left", legend.values.rnd = -2,
                     legend.var2.values.order = c("positive", "negative"),
                     legend.var.title.txt = "Absolute Deviation\n(Income redistribution)",
                     col = c("#ff000050","#0000ff50"), legend.var2.pos = "n",
                     legend.var.style = "e", inches = 0.2)
# add EPT boundaries
plot(st_geometry(ept), add=TRUE)
# add a layout
layoutLayer(title = "Territorial Deviation (reference : EPT)",
            sources = "GEOFLA<U+00AE> 2015 v2.1, Apur, impots.gouv.fr",
            north = TRUE, scale = 5, tabtitle = TRUE, frame = FALSE, theme = "red.pal",
            author = "MTA")
# }