Search code examples
rggplot2usmap

How to label numbers instead of names using usmap?

I know usmap has an option label in plot_usmap(). Instead of state names, I want to label some numbers. I guess there should be data related to the coordinate of the state centroids in usmap but I am not sure how to find it. If I can get the coordinates then I can label numbers with geom_text().

Here is my data.

 State                Abbrev Code  n_votes Attitude              fips 
 1 Alabama              Ala.   AL          9 Solid Republican      01   
 2 Alaska               Alaska AK          3 Toss-up               02   
 3 Arizona              Ariz.  AZ         11 Toss-up               04   
 4 Arkansas             Ark.   AR          6 Solid Republican      05   
 5 California           Calif. CA         55 Solid Democrat        06   
 6 Colorado             Colo.  CO          9 Leaning to Democrat   08   
 7 Connecticut          Conn.  CT          7 Solid Democrat        09   
 8 Delaware             Del.   DE          3 Solid Democrat        10   
 9 District of Columbia D.C.   DC          3 Solid Democrat        11   
10 Florida              Fla.   FL         29 Leaning to Democrat   12   
11 Georgia              Ga.    GA         16 Toss-up               13   
12 Hawaii               Hawaii HI          4 Solid Democrat        15   
13 Idaho                Idaho  ID          4 Solid Republican      16   
14 Illinois             Ill.   IL         20 Solid Democrat        17   
15 Indiana              Ind.   IN         11 Leaning to Republican 18   
16 Iowa                 Iowa   IA          6 Leaning to Republican 19   
17 Kansas               Kans.  KS          6 Leaning to Republican 20   
18 Kentucky             Ky.    KY          8 Solid Republican      21   
19 Louisiana            La.    LA          8 Solid Republican      22   
20 Maine                Maine  ME          2 Solid Democrat        23   
21 Maryland             Md.    MD         10 Solid Democrat        24   
22 Massachusetts        Mass.  MA         11 Solid Democrat        25   
23 Michigan             Mich.  MI         16 Leaning to Democrat   26   
24 Minnesota            Minn.  MN         10 Toss-up               27   
25 Mississippi          Miss.  MS          6 Solid Republican      28   
26 Missouri             Mo.    MO         10 Leaning to Republican 29   
27 Montana              Mont.  MT          3 Solid Republican      30   
28 Nebraska             Nebr.  NE          2 Solid Republican      31   
29 Nevada               Nev.   NV          6 Leaning to Democrat   32   
30 New Hampshire        N.H.   NH          4 Leaning to Democrat   33   
31 New Jersey           N.J.   NJ         14 Solid Democrat        34   
32 New Mexico           N.M.   NM          5 Solid Democrat        35   
33 New York             N.Y.   NY         29 Solid Democrat        36   
34 North Carolina       N.C.   NC         15 Toss-up               37   
35 North Dakota         N.D.   ND          3 Solid Republican      38   
36 Ohio                 Ohio   OH         18 Toss-up               39   
37 Oklahoma             Okla.  OK          7 Solid Republican      40   
38 Oregon               Ore.   OR          7 Solid Democrat        41   
39 Pennsylvania         Pa.    PA         20 Leaning to Democrat   42   
40 Rhode Island         R.I.   RI          4 Solid Democrat        44   
41 South Carolina       S.C.   SC          9 Toss-up               45   
42 South Dakota         S.D.   SD          3 Solid Republican      46   
43 Tennessee            Tenn.  TN         11 Solid Republican      47   
44 Texas                Tex.   TX         38 Toss-up               48   
45 Utah                 Utah   UT          6 Leaning to Republican 49   
46 Vermont              Vt.    VT          3 Solid Democrat        50   
47 Virginia             Va.    VA         13 Leaning to Democrat   51   
48 Washington           Wash.  WA         12 Solid Democrat        53   
49 West Virginia        W.Va.  WV          5 Solid Republican      54   
50 Wisconsin            Wis.   WI         10 Leaning to Democrat   55   
51 Wyoming              Wyo.   WY          3 Solid Republican      56

I would like to label n_votes, it should be something like enter image description here. How am I supposed to do that?

Thanks,

Dan

Solution

  • Update The usmap has been modernized in version 0.7.0 and now returns map data as simple features, i.e. geom_text will no longer work. Instead we have to switch to geom_sf_text:

    library(usmap)
library(ggplot2)

# Get centroids
centroid_labels <- usmapdata::centroid_labels("states")

# Join data to centroids
data_labels <- merge(centroid_labels, statepop, by = "fips")

plot_usmap(data = statepop, values = "pop_2015", color = "white", labels = FALSE) +
  guides(fill = "none") +
  geom_sf_text(data = data_labels, ggplot2::aes(
    label = scales::number(pop_2015, scale = 1e-3, accuracy = 1)
  ), color = "white")

    Original answer

    This could be achieved like so:

    1. Get the coordinates of the state centroids which are included as data in package usmapdata.

    2. Join your dataset to the df with the coordinates

    3. Use geom_text to label the map with your data

    As it would take some time to read and tidy the data you provided (Next time: Type dput(NAME_OF_DATASET) in the console and copy & paste the output starting with structure(... into your post) I simply use the statepop data provided by package usmap as example data:

    library(usmap)
library(ggplot2)

# Get centroids
centroid_labels <- usmapdata::centroid_labels("states")

# Join data to centroids
data_labels <- merge(centroid_labels, statepop, by = "fips")

plot_usmap(data = statepop, values = "pop_2015", color = "white", labels = FALSE) +
  guides(fill = "none") +
  geom_text(data = data_labels, ggplot2::aes(
    x = x, y = y,
    label = scales::number(pop_2015, scale = 1e-3, accuracy = 1)
  ), color = "white")