Choropleth maps

Théo Boulakia

25 septembre 2024

Get started

Packages

library(tidyverse)
library(sf)
library(classInt)
library(rcartocolor)
library(colorBlindness)
library(ggspatial)

Data

Verbalisations pour non respect du confinement

verbalisations = read_csv("data/verbalisations_departement.csv")

Population adulte et population totale

population = read_csv("data/population_departement.csv")

Policiers municipaux en 2020

policiers = read_csv("data/policiers_municipaux_departements.csv")

Voisins vigilants en mai 2020

vigilants = read_csv("data/vigilants_departements.csv")

Contours des départements

departements_sf = st_read("data/departements.gpkg", quiet = TRUE)

Sources

Join

Fines

verbalisations
# A tibble: 101 × 2
   code  verbalisations
   <chr>          <dbl>
 1 01              8036
 2 02             11532
 3 03              3820
 4 04              2341
 5 05              1974
 6 06             40480
 7 07              3939
 8 08              4032
 9 09              2468
10 10              5212
# ℹ 91 more rows

Population

population
# A tibble: 101 × 3
   code  pop_adulte pop_totale
   <chr>      <dbl>      <dbl>
 1 01        528411     657856
 2 02        431728     529374
 3 03        285728     335628
 4 04        139754     165451
 5 05        118744     140605
 6 06        925569    1097410
 7 07        275785     329325
 8 08        222569     269701
 9 09        130458     153954
10 10        255060     311435
# ℹ 91 more rows

How to merge ?

codeverbalisations
018036
0211532
033820
042341
051974
0640480
073939
084032
092468
codepop_adultepop_totale
01528411657856
02431728529374
03285728335628
04139754165451
05118744140605
069255691097410
07275785329325
08222569269701
09130458153954

A common key

codeverbalisations
018036
0211532
033820
042341
051974
0640480
073939
084032
092468
codepop_adultepop_totale
01528411657856
02431728529374
03285728335628
04139754165451
05118744140605
069255691097410
07275785329325
08222569269701
09130458153954

Syntax

left_join(verbalisations, population, by = "code")
# A tibble: 101 × 4
   code  verbalisations pop_adulte pop_totale
   <chr>          <dbl>      <dbl>      <dbl>
 1 01              8036     528411     657856
 2 02             11532     431728     529374
 3 03              3820     285728     335628
 4 04              2341     139754     165451
 5 05              1974     118744     140605
 6 06             40480     925569    1097410
 7 07              3939     275785     329325
 8 08              4032     222569     269701
 9 09              2468     130458     153954
10 10              5212     255060     311435
# ℹ 91 more rows

Principle

Polygons

departements_sf
Simple feature collection with 101 features and 2 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: -5.141277 ymin: 40.28472 xmax: 9.559956 ymax: 51.08899
Geodetic CRS:  WGS 84
First 10 features:
   code                     nom                           geom
1    01                     Ain MULTIPOLYGON (((5.897201 46...
2    02                   Aisne MULTIPOLYGON (((3.687477 49...
3    03                  Allier MULTIPOLYGON (((2.385871 46...
4    04 Alpes-de-Haute-Provence MULTIPOLYGON (((6.66765 43....
5    05            Hautes-Alpes MULTIPOLYGON (((6.641667 44...
6    06         Alpes-Maritimes MULTIPOLYGON (((7.329573 43...
7    07                 Ardèche MULTIPOLYGON (((4.288497 44...
8    08                Ardennes MULTIPOLYGON (((5.308547 49...
9    09                  Ariège MULTIPOLYGON (((1.493896 42...
10   10                    Aube MULTIPOLYGON (((3.650654 48...

Map

ggplot(departements_sf) +
  geom_sf()

Same principle

left_join(departements_sf, verbalisations, by = "code")
Simple feature collection with 101 features and 3 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: -5.141277 ymin: 40.28472 xmax: 9.559956 ymax: 51.08899
Geodetic CRS:  WGS 84
First 10 features:
   code                     nom verbalisations                           geom
1    01                     Ain           8036 MULTIPOLYGON (((5.897201 46...
2    02                   Aisne          11532 MULTIPOLYGON (((3.687477 49...
3    03                  Allier           3820 MULTIPOLYGON (((2.385871 46...
4    04 Alpes-de-Haute-Provence           2341 MULTIPOLYGON (((6.66765 43....
5    05            Hautes-Alpes           1974 MULTIPOLYGON (((6.641667 44...
6    06         Alpes-Maritimes          40480 MULTIPOLYGON (((7.329573 43...
7    07                 Ardèche           3939 MULTIPOLYGON (((4.288497 44...
8    08                Ardennes           4032 MULTIPOLYGON (((5.308547 49...
9    09                  Ariège           2468 MULTIPOLYGON (((1.493896 42...
10   10                    Aube           5212 MULTIPOLYGON (((3.650654 48...

Mutate

departements = left_join(departements_sf, verbalisations, by = "code") |> 
  left_join(population, by = "code") |> 
  mutate(verbalisations_pmla = verbalisations / pop_adulte * 1000)

Inspect

departements
Simple feature collection with 101 features and 6 fields
Geometry type: MULTIPOLYGON
Dimension:     XY
Bounding box:  xmin: -5.141277 ymin: 40.28472 xmax: 9.559956 ymax: 51.08899
Geodetic CRS:  WGS 84
First 10 features:
   code                     nom verbalisations pop_adulte pop_totale
1    01                     Ain           8036     528411     657856
2    02                   Aisne          11532     431728     529374
3    03                  Allier           3820     285728     335628
4    04 Alpes-de-Haute-Provence           2341     139754     165451
5    05            Hautes-Alpes           1974     118744     140605
6    06         Alpes-Maritimes          40480     925569    1097410
7    07                 Ardèche           3939     275785     329325
8    08                Ardennes           4032     222569     269701
9    09                  Ariège           2468     130458     153954
10   10                    Aube           5212     255060     311435
                             geom verbalisations_pmla
1  MULTIPOLYGON (((5.897201 46...            15.20786
2  MULTIPOLYGON (((3.687477 49...            26.71126
3  MULTIPOLYGON (((2.385871 46...            13.36936
4  MULTIPOLYGON (((6.66765 43....            16.75086
5  MULTIPOLYGON (((6.641667 44...            16.62400
6  MULTIPOLYGON (((7.329573 43...            43.73526
7  MULTIPOLYGON (((4.288497 44...            14.28287
8  MULTIPOLYGON (((5.308547 49...            18.11573
9  MULTIPOLYGON (((1.493896 42...            18.91797
10 MULTIPOLYGON (((3.650654 48...            20.43441

Explore

Summary

summary(departements$verbalisations_pmla)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
  9.346  13.860  17.707  19.152  21.355  54.600

Boxplot

ggplot(departements, aes(y = verbalisations_pmla)) +
  geom_boxplot()

Histogram

ggplot(departements, aes(x = verbalisations_pmla)) +
  geom_histogram()

Density

ggplot(departements, aes(x = verbalisations_pmla)) +
  geom_density()

Bar

ggplot(departements, aes(x = nom, y = verbalisations_pmla))+
  geom_bar(stat = "identity")

Better bar

sf

ggplot(departements, aes(fill = verbalisations_pmla)) +
  geom_sf()

Color

Color names

colors()
  [1] "white"                "aliceblue"            "antiquewhite"        
  [4] "antiquewhite1"        "antiquewhite2"        "antiquewhite3"       
  [7] "antiquewhite4"        "aquamarine"           "aquamarine1"         
 [10] "aquamarine2"          "aquamarine3"          "aquamarine4"         
 [13] "azure"                "azure1"               "azure2"              
 [16] "azure3"               "azure4"               "beige"               
 [19] "bisque"               "bisque1"              "bisque2"             
 [22] "bisque3"              "bisque4"              "black"               
 [25] "blanchedalmond"       "blue"                 "blue1"               
 [28] "blue2"                "blue3"                "blue4"               
 [31] "blueviolet"           "brown"                "brown1"              
 [34] "brown2"               "brown3"               "brown4"              
 [37] "burlywood"            "burlywood1"           "burlywood2"          
 [40] "burlywood3"           "burlywood4"           "cadetblue"           
 [43] "cadetblue1"           "cadetblue2"           "cadetblue3"          
 [46] "cadetblue4"           "chartreuse"           "chartreuse1"         
 [49] "chartreuse2"          "chartreuse3"          "chartreuse4"         
 [52] "chocolate"            "chocolate1"           "chocolate2"          
 [55] "chocolate3"           "chocolate4"           "coral"               
 [58] "coral1"               "coral2"               "coral3"              
 [61] "coral4"               "cornflowerblue"       "cornsilk"            
 [64] "cornsilk1"            "cornsilk2"            "cornsilk3"           
 [67] "cornsilk4"            "cyan"                 "cyan1"               
 [70] "cyan2"                "cyan3"                "cyan4"               
 [73] "darkblue"             "darkcyan"             "darkgoldenrod"       
 [76] "darkgoldenrod1"       "darkgoldenrod2"       "darkgoldenrod3"      
 [79] "darkgoldenrod4"       "darkgray"             "darkgreen"           
 [82] "darkgrey"             "darkkhaki"            "darkmagenta"         
 [85] "darkolivegreen"       "darkolivegreen1"      "darkolivegreen2"     
 [88] "darkolivegreen3"      "darkolivegreen4"      "darkorange"          
 [91] "darkorange1"          "darkorange2"          "darkorange3"         
 [94] "darkorange4"          "darkorchid"           "darkorchid1"         
 [97] "darkorchid2"          "darkorchid3"          "darkorchid4"         
[100] "darkred"              "darksalmon"           "darkseagreen"        
[103] "darkseagreen1"        "darkseagreen2"        "darkseagreen3"       
[106] "darkseagreen4"        "darkslateblue"        "darkslategray"       
[109] "darkslategray1"       "darkslategray2"       "darkslategray3"      
[112] "darkslategray4"       "darkslategrey"        "darkturquoise"       
[115] "darkviolet"           "deeppink"             "deeppink1"           
[118] "deeppink2"            "deeppink3"            "deeppink4"           
[121] "deepskyblue"          "deepskyblue1"         "deepskyblue2"        
[124] "deepskyblue3"         "deepskyblue4"         "dimgray"             
[127] "dimgrey"              "dodgerblue"           "dodgerblue1"         
[130] "dodgerblue2"          "dodgerblue3"          "dodgerblue4"         
[133] "firebrick"            "firebrick1"           "firebrick2"          
[136] "firebrick3"           "firebrick4"           "floralwhite"         
[139] "forestgreen"          "gainsboro"            "ghostwhite"          
[142] "gold"                 "gold1"                "gold2"               
[145] "gold3"                "gold4"                "goldenrod"           
[148] "goldenrod1"           "goldenrod2"           "goldenrod3"          
[151] "goldenrod4"           "gray"                 "gray0"               
[154] "gray1"                "gray2"                "gray3"               
[157] "gray4"                "gray5"                "gray6"               
[160] "gray7"                "gray8"                "gray9"               
[163] "gray10"               "gray11"               "gray12"              
[166] "gray13"               "gray14"               "gray15"              
[169] "gray16"               "gray17"               "gray18"              
[172] "gray19"               "gray20"               "gray21"              
[175] "gray22"               "gray23"               "gray24"              
[178] "gray25"               "gray26"               "gray27"              
[181] "gray28"               "gray29"               "gray30"              
[184] "gray31"               "gray32"               "gray33"              
[187] "gray34"               "gray35"               "gray36"              
[190] "gray37"               "gray38"               "gray39"              
[193] "gray40"               "gray41"               "gray42"              
[196] "gray43"               "gray44"               "gray45"              
[199] "gray46"               "gray47"               "gray48"              
[202] "gray49"               "gray50"               "gray51"              
[205] "gray52"               "gray53"               "gray54"              
[208] "gray55"               "gray56"               "gray57"              
[211] "gray58"               "gray59"               "gray60"              
[214] "gray61"               "gray62"               "gray63"              
[217] "gray64"               "gray65"               "gray66"              
[220] "gray67"               "gray68"               "gray69"              
[223] "gray70"               "gray71"               "gray72"              
[226] "gray73"               "gray74"               "gray75"              
[229] "gray76"               "gray77"               "gray78"              
[232] "gray79"               "gray80"               "gray81"              
[235] "gray82"               "gray83"               "gray84"              
[238] "gray85"               "gray86"               "gray87"              
[241] "gray88"               "gray89"               "gray90"              
[244] "gray91"               "gray92"               "gray93"              
[247] "gray94"               "gray95"               "gray96"              
[250] "gray97"               "gray98"               "gray99"              
[253] "gray100"              "green"                "green1"              
[256] "green2"               "green3"               "green4"              
[259] "greenyellow"          "grey"                 "grey0"               
[262] "grey1"                "grey2"                "grey3"               
[265] "grey4"                "grey5"                "grey6"               
[268] "grey7"                "grey8"                "grey9"               
[271] "grey10"               "grey11"               "grey12"              
[274] "grey13"               "grey14"               "grey15"              
[277] "grey16"               "grey17"               "grey18"              
[280] "grey19"               "grey20"               "grey21"              
[283] "grey22"               "grey23"               "grey24"              
[286] "grey25"               "grey26"               "grey27"              
[289] "grey28"               "grey29"               "grey30"              
[292] "grey31"               "grey32"               "grey33"              
[295] "grey34"               "grey35"               "grey36"              
[298] "grey37"               "grey38"               "grey39"              
[301] "grey40"               "grey41"               "grey42"              
[304] "grey43"               "grey44"               "grey45"              
[307] "grey46"               "grey47"               "grey48"              
[310] "grey49"               "grey50"               "grey51"              
[313] "grey52"               "grey53"               "grey54"              
[316] "grey55"               "grey56"               "grey57"              
[319] "grey58"               "grey59"               "grey60"              
[322] "grey61"               "grey62"               "grey63"              
[325] "grey64"               "grey65"               "grey66"              
[328] "grey67"               "grey68"               "grey69"              
[331] "grey70"               "grey71"               "grey72"              
[334] "grey73"               "grey74"               "grey75"              
[337] "grey76"               "grey77"               "grey78"              
[340] "grey79"               "grey80"               "grey81"              
[343] "grey82"               "grey83"               "grey84"              
[346] "grey85"               "grey86"               "grey87"              
[349] "grey88"               "grey89"               "grey90"              
[352] "grey91"               "grey92"               "grey93"              
[355] "grey94"               "grey95"               "grey96"              
[358] "grey97"               "grey98"               "grey99"              
[361] "grey100"              "honeydew"             "honeydew1"           
[364] "honeydew2"            "honeydew3"            "honeydew4"           
[367] "hotpink"              "hotpink1"             "hotpink2"            
[370] "hotpink3"             "hotpink4"             "indianred"           
[373] "indianred1"           "indianred2"           "indianred3"          
[376] "indianred4"           "ivory"                "ivory1"              
[379] "ivory2"               "ivory3"               "ivory4"              
[382] "khaki"                "khaki1"               "khaki2"              
[385] "khaki3"               "khaki4"               "lavender"            
[388] "lavenderblush"        "lavenderblush1"       "lavenderblush2"      
[391] "lavenderblush3"       "lavenderblush4"       "lawngreen"           
[394] "lemonchiffon"         "lemonchiffon1"        "lemonchiffon2"       
[397] "lemonchiffon3"        "lemonchiffon4"        "lightblue"           
[400] "lightblue1"           "lightblue2"           "lightblue3"          
[403] "lightblue4"           "lightcoral"           "lightcyan"           
[406] "lightcyan1"           "lightcyan2"           "lightcyan3"          
[409] "lightcyan4"           "lightgoldenrod"       "lightgoldenrod1"     
[412] "lightgoldenrod2"      "lightgoldenrod3"      "lightgoldenrod4"     
[415] "lightgoldenrodyellow" "lightgray"            "lightgreen"          
[418] "lightgrey"            "lightpink"            "lightpink1"          
[421] "lightpink2"           "lightpink3"           "lightpink4"          
[424] "lightsalmon"          "lightsalmon1"         "lightsalmon2"        
[427] "lightsalmon3"         "lightsalmon4"         "lightseagreen"       
[430] "lightskyblue"         "lightskyblue1"        "lightskyblue2"       
[433] "lightskyblue3"        "lightskyblue4"        "lightslateblue"      
[436] "lightslategray"       "lightslategrey"       "lightsteelblue"      
[439] "lightsteelblue1"      "lightsteelblue2"      "lightsteelblue3"     
[442] "lightsteelblue4"      "lightyellow"          "lightyellow1"        
[445] "lightyellow2"         "lightyellow3"         "lightyellow4"        
[448] "limegreen"            "linen"                "magenta"             
[451] "magenta1"             "magenta2"             "magenta3"            
[454] "magenta4"             "maroon"               "maroon1"             
[457] "maroon2"              "maroon3"              "maroon4"             
[460] "mediumaquamarine"     "mediumblue"           "mediumorchid"        
[463] "mediumorchid1"        "mediumorchid2"        "mediumorchid3"       
[466] "mediumorchid4"        "mediumpurple"         "mediumpurple1"       
[469] "mediumpurple2"        "mediumpurple3"        "mediumpurple4"       
[472] "mediumseagreen"       "mediumslateblue"      "mediumspringgreen"   
[475] "mediumturquoise"      "mediumvioletred"      "midnightblue"        
[478] "mintcream"            "mistyrose"            "mistyrose1"          
[481] "mistyrose2"           "mistyrose3"           "mistyrose4"          
[484] "moccasin"             "navajowhite"          "navajowhite1"        
[487] "navajowhite2"         "navajowhite3"         "navajowhite4"        
[490] "navy"                 "navyblue"             "oldlace"             
[493] "olivedrab"            "olivedrab1"           "olivedrab2"          
[496] "olivedrab3"           "olivedrab4"           "orange"              
[499] "orange1"              "orange2"              "orange3"             
[502] "orange4"              "orangered"            "orangered1"          
[505] "orangered2"           "orangered3"           "orangered4"          
[508] "orchid"               "orchid1"              "orchid2"             
[511] "orchid3"              "orchid4"              "palegoldenrod"       
[514] "palegreen"            "palegreen1"           "palegreen2"          
[517] "palegreen3"           "palegreen4"           "paleturquoise"       
[520] "paleturquoise1"       "paleturquoise2"       "paleturquoise3"      
[523] "paleturquoise4"       "palevioletred"        "palevioletred1"      
[526] "palevioletred2"       "palevioletred3"       "palevioletred4"      
[529] "papayawhip"           "peachpuff"            "peachpuff1"          
[532] "peachpuff2"           "peachpuff3"           "peachpuff4"          
[535] "peru"                 "pink"                 "pink1"               
[538] "pink2"                "pink3"                "pink4"               
[541] "plum"                 "plum1"                "plum2"               
[544] "plum3"                "plum4"                "powderblue"          
[547] "purple"               "purple1"              "purple2"             
[550] "purple3"              "purple4"              "red"                 
[553] "red1"                 "red2"                 "red3"                
[556] "red4"                 "rosybrown"            "rosybrown1"          
[559] "rosybrown2"           "rosybrown3"           "rosybrown4"          
[562] "royalblue"            "royalblue1"           "royalblue2"          
[565] "royalblue3"           "royalblue4"           "saddlebrown"         
[568] "salmon"               "salmon1"              "salmon2"             
[571] "salmon3"              "salmon4"              "sandybrown"          
[574] "seagreen"             "seagreen1"            "seagreen2"           
[577] "seagreen3"            "seagreen4"            "seashell"            
[580] "seashell1"            "seashell2"            "seashell3"           
[583] "seashell4"            "sienna"               "sienna1"             
[586] "sienna2"              "sienna3"              "sienna4"             
[589] "skyblue"              "skyblue1"             "skyblue2"            
[592] "skyblue3"             "skyblue4"             "slateblue"           
[595] "slateblue1"           "slateblue2"           "slateblue3"          
[598] "slateblue4"           "slategray"            "slategray1"          
[601] "slategray2"           "slategray3"           "slategray4"          
[604] "slategrey"            "snow"                 "snow1"               
[607] "snow2"                "snow3"                "snow4"               
[610] "springgreen"          "springgreen1"         "springgreen2"        
[613] "springgreen3"         "springgreen4"         "steelblue"           
[616] "steelblue1"           "steelblue2"           "steelblue3"          
[619] "steelblue4"           "tan"                  "tan1"                
[622] "tan2"                 "tan3"                 "tan4"                
[625] "thistle"              "thistle1"             "thistle2"            
[628] "thistle3"             "thistle4"             "tomato"              
[631] "tomato1"              "tomato2"              "tomato3"             
[634] "tomato4"              "turquoise"            "turquoise1"          
[637] "turquoise2"           "turquoise3"           "turquoise4"          
[640] "violet"               "violetred"            "violetred1"          
[643] "violetred2"           "violetred3"           "violetred4"          
[646] "wheat"                "wheat1"               "wheat2"              
[649] "wheat3"               "wheat4"               "whitesmoke"          
[652] "yellow"               "yellow1"              "yellow2"             
[655] "yellow3"              "yellow4"              "yellowgreen"         
length(colors())
[1] 657

aquamarine4

ggplot(departements_sf) +
  geom_sf(fill = "aquamarine4")

#FF6347

ggplot(departements_sf) +
  geom_sf(fill = "#FF6347")

Color codes

  • Hexadecimal symbols : 0:9, A:F.
  • White : #FFFFFF
  • Black : #000000
  • Red : #FF0000
  • Green : #00FF00
  • Blue : #0000FF
  • Brown : #A52A2A

Palettes

Sequential

Discrete

Diverging

R packages

Color blindness

Rainbow

colorBlindness::displayAllColors(rainbow(6))

Viridis

colorBlindness::displayAllColors(viridis::viridis(6))

Antique

displayAllColors(rcartocolor::carto_pal(n = 6, name = "Antique"))

Color scales

Save typing

default = ggplot(departements,
                 aes(fill = verbalisations_pmla)) +
  geom_sf() +
  theme_void()

Default

default

Fill continuous

default + scale_fill_continuous()

Gradient

default + scale_fill_gradient(low = "#132B43", high = "#56B1F7")

Red Gradient

default + scale_fill_gradient(low = "#43000D", high = "#F76A6A")

Viridis

default + scale_fill_viridis_c()

Viridis magma

default + scale_fill_viridis_c(option = "magma")

Viridis inferno

default + scale_fill_viridis_c(option = "inferno")

Rcartocolor

default + scale_fill_carto_c(palette = "SunsetDark")

Binned scales

Continuous inferno

default + scale_fill_viridis_c(option = "inferno")

Binned inferno

default + scale_fill_viridis_b(option = "inferno")

ClassInt package

Equal intervals

equal = classIntervals(departements$verbalisations_pmla,
                       n = 4, 
                       style = "equal")
equal$brks
[1]  9.346372 20.659784 31.973197 43.286609 54.600022

Quantiles

quantile = classIntervals(departements$verbalisations_pmla,
                          n = 4,
                          style = "quantile")
quantile$brks
[1]  9.346372 13.859919 17.707087 21.354589 54.600022

Boxplot

box = classIntervals(departements$verbalisations_pmla,
                     style = "box")
box$brks
[1]      -Inf  2.617913 13.859919 17.707087 21.354589 32.596594 54.600022

Visualize classification

Tools

Code 
htmp = ggplot(departements, 
              aes(x = fct_reorder(nom, verbalisations_pmla),
                  y = 1,
                  fill = verbalisations_pmla)) +
  geom_raster() +
  guides(fill = "none") +
  theme_void() +
  theme(aspect.ratio = 4/10)
Code 
points = ggplot(departements, aes(x = verbalisations_pmla,
                                  y = 0)) +
  geom_point(size = 4,
             aes(
               # alpha = verbalisations_pmla,
               colour = verbalisations_pmla)) +
  guides(colour = "none",
         # alpha = "none"
  ) +
  ggrepel::geom_text_repel(aes(label = nom)) +
  theme_void() +
  theme(aspect.ratio = 4/10,
        axis.line.x = element_line(),
        axis.ticks.x = element_line(),
        axis.text.x = element_text(),
        axis.title.x = element_text())

Continuous

points + scale_colour_viridis_c()

Equal intervals

points + scale_colour_viridis_b(breaks = equal$brk)

Quantiles

points + scale_colour_viridis_b(breaks = quantile$brk)

Boxplot

points + scale_colour_viridis_b(breaks = box$brk)

Corresponding Maps

Equal intervals

default + scale_fill_viridis_b(breaks = equal$brk)

Quantiles

default + scale_fill_viridis_b(breaks = quantile$brk)

Boxplot

default + scale_fill_viridis_b(breaks = box$brk)

Heavy tailed distributions

Problem

ggplot(departements, aes(x = verbalisations_pmla)) +
  geom_density()

Head/Tail breaks algorithm

Jiang, Bin. 2013. “Head/Tail Breaks: A New Classification Scheme for Data with a Heavy-Tailed Distribution.” The Professional Geographer 65 (3): 482–94.

  1. Compute mu = mean(var).
  2. Break var into the tail (as var < mu) and the head (as var > mu).
  3. Assess if the proportion of head over var is lower or equal than a given threshold (i.e. length(head)/length(var) <= thr)
  4. If 3 is TRUE, repeat 1 to 3 until the condition is FALSE or no more partitions are possible (i.e. head has less than two elements expressed as length(head) < 2).

Implementation in ClassInt

headtails = classIntervals(departements$verbalisations_pmla,
                           style = "headtails")
headtails$brks
[1]  9.346372 19.152204 26.291928 54.600022

Visualize

points + scale_colour_viridis_b(breaks = headtails$brk)

Map

default + scale_fill_viridis_b(breaks = headtails$brk)

Polishing

Legend

Code 
default + scale_fill_viridis_b(breaks = headtails$brk,
                               labels = round) +
  labs(fill = "Verbalisations\npour\n1000 adultes")

Title

Code 
default + scale_fill_viridis_b(breaks = headtails$brk,
                               labels = round) +
  labs(title = "Verbalisations pour non-respect du confinement",
       subtitle = "Entre le 17 mars et le 10 mai 2020",
       fill = "Verbalisations\npour\n1000 adultes",
       caption = "Source : ANTAI")

North arrow

Code 
default + scale_fill_viridis_b(breaks = headtails$brk,
                               labels = round) +
  labs(title = "Verbalisations pour non-respect du confinement",
       subtitle = "Entre le 17 mars et le 10 mai 2020",
       fill = "Verbalisations\npour\n1000 adultes",
       caption = "Source : ANTAI") +
  annotation_north_arrow(style = north_arrow_nautical(),
                         location = "tl")

Scale bar

Code 
default + scale_fill_viridis_b(breaks = headtails$brk,
                               labels = round) +
  labs(title = "Verbalisations pour non-respect du confinement",
       subtitle = "Entre le 17 mars et le 10 mai 2020",
       fill = "Verbalisations\npour\n1000 adultes",
       caption = "Source : ANTAI") +
  annotation_north_arrow(style = north_arrow_nautical(),
                         location = "tl") +
  annotation_scale(location = "br")