choromap: Draws a choropleth map

In choisy/poseid: Population-based Observational Studies of the Epidemiology of Infectious Diseases

Description

Draws a choropleth map

Usage

choromap(df, map, fixedBreaks, col = heat.colors(6), col_na = "grey",
  ...)

Arguments

df	a data frame containing at two colums, one of class "character" and one of class "numeric".
map	an object of class "SpatialPolygonsDataFrame" containing at least one column containing the same observations and name as the character column of the dataframe df
fixedBreaks	a vector of value used to specife the class intervals.
col	a vector of colors to use for the map (by default, col = heat.colors(6))
col_na	the color with which to represent the missing values (by default col_na = "grey")
...	arguments to be passed to plot

Details

It's important that the parameters df and map has one columns in commun, to be able to link them.

Value

A numeric vector containing the breaks value and the attributes colors corresponding to the color associated with the breaks value, returned invisibly.

Examples

library(gdpm)
library(magrittr)
library(gadmVN)

# dengue data
dengue <- getid(dengue, from = 1990, to = 2010)
# geographic data
map <- gadmVN::gadm(date = 1990, merge_hanoi = TRUE) %>% sf::as_Spatial()

# A choroplet map of the dengue data:
# The first step is to select only the month and the year that we want to
# represent, here the incidence value of dengue in September 1993. We keep
# only the 'province' and 'incidence_dengue' column as the 'choromap'
# function accept only dataframe of the two columns in entry.
# The second step is to print the map.
# The last step is to print a legend, here we use legend2 of the 'poseid'
# package but other function can be used.
library(dplyr)
dengue_0993  <- filter(dengue, year == 1993, month == "September")
dengue_0993 <- select(dengue_0993, province, contains("incidence"))
a <- choromap(dengue_0993, map, fixedBreaks = c(0,10,50,100,500,1000,2000))
# return invisibly the information for the legend
legend2(legend = a, col = attr(a, "colors"), col_na = "grey")

# You can also use the '%>%' operator:
dengue_0993 %>%
  choromap(map, fixedBreaks = c(0,10,50,100,500,1000,2000)) %>%
  legend2(legend = ., col = attr(., "colors"), col_na = "grey")

# Using some other color palettes, for examples the ones from the
# RColorBrewer package or the one in the color Palettes of R, be careful
# to have a color vector of length n-1 compare to the lenght of fixedBreakss:
library(RColorBrewer)
# to see the available color palettes:
display.brewer.all()
dengue_0993 %>%
 choromap(map, fixedBreaks = c(0,10,50,100,500,1000,2000),
           col = brewer.pal(6, "YlOrRd")) %>%
 legend2(legend = ., col = attr(., "colors"), col_na = "grey")

# changing the color of the missing values:
dengue_0993 %>%
 choromap(map, fixedBreaks = c(0,10,50,100,500,1000,2000),
           col = brewer.pal(6, "YlOrRd"), col_na = "blue") %>%
 legend2(legend = ., col = attr(., "colors"), col_na = "blue")

# drawing a map without border:
dengue_0993 %>%
 choromap(map, fixedBreaks = c(0,10,50,100,500,1000,2000),
           col = brewer.pal(6, "YlOrRd"), col_na = "blue",
           border = NA) %>%
 legend2(legend = ., col = attr(., "colors"), col_na = "blue")

choisy/poseid documentation built on Aug. 22, 2019, 4:45 a.m.