Previous map versions
Load the required libraries, functions and data objects
Functions
Convenience definitions
Load and transform the basemap
Display
Next up
Disclaimer
Credits
License

Previous map versions

For the 48-state plus District of Columbia case and saved functions and objects used here, see the walkthrough installment. For the 50-state version plus District of Columbia with Alaska and Hawaii scaled and relocated, see the inset installment.

Load the required libraries, functions and data objects

Libraries

x = c("ggplot2", "rgdal", "maptools", "mapproj", "rgeos")
lapply(x, library, character.only = TRUE)

## [[1]]
## [1] "ggplot2"   "stats"     "graphics"  "grDevices" "utils"     "datasets" 
## [7] "methods"   "base"     
## 
## [[2]]
##  [1] "rgdal"     "sp"        "ggplot2"   "stats"     "graphics" 
##  [6] "grDevices" "utils"     "datasets"  "methods"   "base"     
## 
## [[3]]
##  [1] "maptools"  "rgdal"     "sp"        "ggplot2"   "stats"    
##  [6] "graphics"  "grDevices" "utils"     "datasets"  "methods"  
## [11] "base"     
## 
## [[4]]
##  [1] "mapproj"   "maps"      "maptools"  "rgdal"     "sp"       
##  [6] "ggplot2"   "stats"     "graphics"  "grDevices" "utils"    
## [11] "datasets"  "methods"   "base"     
## 
## [[5]]
##  [1] "rgeos"     "mapproj"   "maps"      "maptools"  "rgdal"    
##  [6] "sp"        "ggplot2"   "stats"     "graphics"  "grDevices"
## [11] "utils"     "datasets"  "methods"   "base"

Functions

remove.territories = function(.df) {
    subset(.df, 
        .df$id != "AS" &
        .df$id != "MP" &
        .df$id != "GU" & 
        .df$id != "PR" &
        .df$id != "VI" 
    )
}
#save("remove.territories", file = "helpers/remove.territories")

Convenience definitions

plain_theme = theme(axis.text=element_blank()) + 
    theme(panel.background = element_blank(), 
        panel.grid = element_blank(), 
        axis.ticks = element_blank())

no_ylab = ylab("") 
no_xlab = xlab("")

Load and transform the basemap

setwd("~/Desktop/gitmo/playpen/r")
load("data/cb5")
us = cb5

Transform geographical coordinates to Lambert Azimuth Equal Area projection

us_aea = spTransform(us, CRS("+proj=laea +lat_0=45 +lon_0=-100 +x_0=0 +y_0=0 +a=6370997 +b=6370997 +units=m +no_defs"))
us_aea@data$id = rownames(us_aea@data)

Move Alaska (scaled down) and Hawaii

alaska = us_aea[us_aea$STATEFP=="02",]
alaska = elide(alaska, rotate=-50)
alaska = elide(alaska, scale=max(apply(bbox(alaska), 1, diff)) / 2.3)
alaska = elide(alaska, shift=c(-2100000, -2500000))
proj4string(alaska) = proj4string(us_aea)

hawaii = us_aea[us_aea$STATEFP=="15",]
hawaii = elide(hawaii, rotate=-35)
hawaii = elide(hawaii, shift=c(5400000, -1400000))
proj4string(hawaii) = proj4string(us_aea)

Remove Alaska and Hawaii from base map and substitute transformed versions

us_aea = us_aea[!us_aea$STATEFP %in% c("02", "15"),]
us_aea = rbind(us_aea, alaska, hawaii)

Move Rhode Island, Delaware and the District of Columbia

rhode_island = us_aea[us_aea$STATEFP=="44",]
rhode_island = elide(rhode_island, shift=c(0,-200000))
proj4string(rhode_island) = proj4string(us_aea)


delaware = us_aea[us_aea$STATEFP=="10",]
delaware = elide(delaware, shift=c(200000,0))
proj4string(delaware) = proj4string(us_aea)

dc = us_aea[us_aea$STATEFP=="11",]
####################################################
#dc = elide(dc, scale=max(apply(bbox(dc), 1, diff)) / .999999) # can't make smaller than 1.0
#
# Scaling of this object is not yet implemented
#
####################################################
dc = elide(dc, shift=c(250000,-125000))
proj4string(dc) = proj4string(us_aea)

Remove Rhode Island , Delaware and the District of Columbia from base map and substitute transformed versions

us_aea = us_aea[!us_aea$STATEFP %in% c("44", "10", "11"),]
us_aea = rbind(us_aea, delaware, rhode_island, dc)

Display

Prepare a data frame for plotting and optionally save

us50 <- fortify(us_aea, region="STUSPS")
us50 = remove.territories(us50)
#save('helpers/us50')

Plot the map

p = ggplot(data=us50) + 
    geom_map(map=us50, aes(x=long, y=lat, map_id=id, group=group), ,fill="white", color="black", size=0.3) + 
    no_ylab + 
    no_xlab + 
    plain_theme
p

sessionInfo()

## R version 3.2.1 (2015-06-18)
## Platform: x86_64-apple-darwin13.4.0 (64-bit)
## Running under: OS X 10.10.4 (Yosemite)
## 
## locale:
## [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
## 
## attached base packages:
## [1] stats     graphics  grDevices utils     datasets  methods   base     
## 
## other attached packages:
## [1] rgeos_0.3-11    mapproj_1.2-3   maps_2.3-10     maptools_0.8-36
## [5] rgdal_1.0-4     sp_1.1-1        ggplot2_1.0.1  
## 
## loaded via a namespace (and not attached):
##  [1] Rcpp_0.11.6      knitr_1.10.5     magrittr_1.5     MASS_7.3-42     
##  [5] munsell_0.4.2    colorspace_1.2-6 lattice_0.20-33  stringr_1.0.0   
##  [9] plyr_1.8.3       tools_3.2.1      grid_3.2.1       gtable_0.1.2    
## [13] htmltools_0.2.6  yaml_2.1.13      digest_0.6.8     reshape2_1.4.1  
## [17] formatR_1.2      evaluate_0.7     rmarkdown_0.7    labeling_0.3    
## [21] stringi_0.5-5    scales_0.2.5     foreign_0.8-65   proto_0.3-10

Next up

Enlarging the District of Columbia and adding state names

Disclaimer

I am unable to answer questions relating to the use of this code under Windows.

Credits

Algorithms

Scale and shift

Data

See sources in the walkthrough installment.

R Packages

Roger Bivand and Nicholas Lewin-Koh (2015). maptools: Tools for Reading and Handling Spatial Objects. R package version 0.8-36. http://CRAN.R-project.org/package=maptools
Roger Bivand and Colin Rundel (2015). rgeos: Interface to Geometry Engine - Open Source (GEOS). R package version 0.3-11. http://CRAN.R-project.org/package=rgeos
Roger Bivand, Tim Keitt and Barry Rowlingson (2015). rgdal: Bindings for the Geospatial Data Abstraction Library. R package version 1.0-4 rgdal
Doug McIlroy. Packaged for R by Ray Brownrigg, Thomas P Minka and transition to Plan 9 codebase by Roger Bivand. (2015). mapproj: Map Projections. R package version 1.2-3. http://CRAN.R-project.org/package=mappro
Erich Neuwirth (2014). RColorBrewer: ColorBrewer Palettes. R package version 1.1-2. RColorBrewer
R Core Team (2015). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. [grid]
H. Wickham. ggplot2: elegant graphics for data analysis. Springer New York, 2009. ggplot2

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Thematic Mapping in R without the Tears, Insets and Outsets

Richard Careaga

July 22, 2015