GIS Tutorial_week10
This tutorial is part of Computerworld’s How to Make a Map with R
In 10 (fairly) Easy Steps https://www.computerworld.com/article/3038270/data-analytics/create-maps-in-r-in-10-fairly-easy-steps.html by Sharon Machlis sharon_machlis@idg.com
# Set various values needed, including names of files and FIPS codes for New Hampshire and South Carolina
nhdatafile <- "NHD2016.xlsx"
nhdatafilecsv <- "NHD2016.csv"
usshapefile <- "cb_2014_us_county_5m/cb_2014_us_county_5m.shp"
nhfipscode <- "33"
scdatafile <- "SCGOP2016.csv"
scfipscode <- "45"Run any of the install.packages() commands below for packages that are not yet on your system
install.packages(“shiny”) install.packages(“urltools”) install.packages(“tmap”) install.packages(“tmaptools”) install.packages(“leaflet”) install.packages(“scales”) install.packages(“leaflet.extras”) install.packages(“rio”) install.packages(“htmlwidgets”) install.packages(“sf”) install.packages(“dplyr”)
Load the tmap, tmaptools, and leaflet packages into your working session:
library(tidyverse)## Warning: package 'tidyverse' was built under R version 4.0.5## -- Attaching packages --------------------------------------- tidyverse 1.3.0 --## v ggplot2 3.3.3 v purrr 0.3.4
## v tibble 3.0.6 v dplyr 1.0.3
## v tidyr 1.1.2 v stringr 1.4.0
## v readr 1.4.0 v forcats 0.5.1## -- Conflicts ------------------------------------------ tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag() masks stats::lag()library(tmap)## Warning: package 'tmap' was built under R version 4.0.5library(tmaptools)## Warning: package 'tmaptools' was built under R version 4.0.5library(leaflet)## Warning: package 'leaflet' was built under R version 4.0.5library(sf)## Warning: package 'sf' was built under R version 4.0.5## Linking to GEOS 3.9.0, GDAL 3.2.1, PROJ 7.2.1library(leaflet.extras)## Warning: package 'leaflet.extras' was built under R version 4.0.5library(dplyr)
library(rio)## Warning: package 'rio' was built under R version 4.0.5library(sp)## Warning: package 'sp' was built under R version 4.0.5Step 1: Read in the NH election results file:
getwd()## [1] "C:/Users/small/Desktop/MCollege/2021/DATA110/week10"setwd("C:/Users/small/Desktop/MCollege/2021/DATA110/week10/GIS")
nhdata <- import(nhdatafile)
#nhdata <- import(nhdatafilecsv)If you have any problems with this, there is also a CSV version of the file – sometimes reading Excel between Mac and Windows can be tricky. Try
nhdata <- rio::import(nhdatafilecsv)
Eliminate columns for minor candidates and just use County, Clinton and Sanders columns:
nhdata <- nhdata[,c("County", "Clinton", "Sanders")]
nhdata## County Clinton Sanders
## 1 Belknap 3495 6005
## 2 Carroll 3230 5638
## 3 Cheshire 5132 12441
## 4 Coos 2013 3639
## 5 Grafton 6918 14245
## 6 Hillsborough 28147 39245
## 7 Merrimack 12250 18107
## 8 Rockingham 22829 31065
## 9 Strafford 8813 15881
## 10 Sullivan 2497 5915Step 2: Decide what data to map
Add columns for percents and margins:
nhdata$SandersMarginVotes <- nhdata$Sanders - nhdata$Clinton
nhdata$SandersPct <- (nhdata$Sanders) / (nhdata$Sanders + nhdata$Clinton)
# Will use formatting later to multiply by a hundred
nhdata$ClintonPct <- (nhdata$Clinton) / (nhdata$Sanders + nhdata$Clinton)
nhdata$SandersMarginPctgPoints <- nhdata$SandersPct - nhdata$ClintonPct
nhdata## County Clinton Sanders SandersMarginVotes SandersPct ClintonPct
## 1 Belknap 3495 6005 2510 0.6321053 0.3678947
## 2 Carroll 3230 5638 2408 0.6357691 0.3642309
## 3 Cheshire 5132 12441 7309 0.7079611 0.2920389
## 4 Coos 2013 3639 1626 0.6438429 0.3561571
## 5 Grafton 6918 14245 7327 0.6731087 0.3268913
## 6 Hillsborough 28147 39245 11098 0.5823392 0.4176608
## 7 Merrimack 12250 18107 5857 0.5964687 0.4035313
## 8 Rockingham 22829 31065 8236 0.5764092 0.4235908
## 9 Strafford 8813 15881 7068 0.6431117 0.3568883
## 10 Sullivan 2497 5915 3418 0.7031621 0.2968379
## SandersMarginPctgPoints
## 1 0.2642105
## 2 0.2715381
## 3 0.4159222
## 4 0.2876858
## 5 0.3462175
## 6 0.1646783
## 7 0.1929374
## 8 0.1528185
## 9 0.2862234
## 10 0.4063243Step 3: Get geographic data files
Read in the shapefile for US states and counties:
If libraries with raster and rgdal don’t work (see next chunk), try library(sf) with the command st_read
All these options are here and should help you get the qtm command in the next chunk
#install.packages("raster")
#install.packages("rgdal")
setwd("C:/Users/small/Desktop/MCollege/2021/DATA110/week10/GIS")
library(raster)## Warning: package 'raster' was built under R version 4.0.5##
## Attaching package: 'raster'## The following object is masked from 'package:dplyr':
##
## select## The following object is masked from 'package:tidyr':
##
## extractlibrary(rgdal)## Warning: package 'rgdal' was built under R version 4.0.5## rgdal: version: 1.5-23, (SVN revision 1121)
## Geospatial Data Abstraction Library extensions to R successfully loaded
## Loaded GDAL runtime: GDAL 3.2.1, released 2020/12/29
## Path to GDAL shared files: C:/Users/small/Documents/R/win-library/4.0/rgdal/gdal
## GDAL binary built with GEOS: TRUE
## Loaded PROJ runtime: Rel. 7.2.1, January 1st, 2021, [PJ_VERSION: 721]
## Path to PROJ shared files: C:/Users/small/Documents/R/win-library/4.0/rgdal/proj
## PROJ CDN enabled: FALSE
## Linking to sp version:1.4-5
## To mute warnings of possible GDAL/OSR exportToProj4() degradation,
## use options("rgdal_show_exportToProj4_warnings"="none") before loading rgdal.
## Overwritten PROJ_LIB was C:/Users/small/Documents/R/win-library/4.0/rgdal/projlibrary(sf)
usgeo <- shapefile("cb_2014_us_county_5m/cb_2014_us_county_5m.shp")## Warning in rgdal::readOGR(dirname(x), fn, stringsAsFactors = stringsAsFactors, :
## Z-dimension discarded#usgeo <- st_read("cb_2014_us_county_5m/cb_2014_us_county_5m.shp")Do a quick plot (qtm stands for quick thematic map) of the shapefile and check its structure:
qtm(usgeo)
# (pause to wait for map to render, may take a few seconds)
view(usgeo)nhgeo <- usgeo[usgeo$STATEFP==nhfipscode,]tmap test plot of the New Hampshire data
qtm(nhgeo)
Structure of the object
str(nhgeo)## Formal class 'SpatialPolygonsDataFrame' [package "sp"] with 5 slots
## ..@ data :'data.frame': 10 obs. of 9 variables:
## .. ..$ STATEFP : chr [1:10] "33" "33" "33" "33" ...
## .. ..$ COUNTYFP: chr [1:10] "009" "011" "007" "001" ...
## .. ..$ COUNTYNS: chr [1:10] "00873178" "00873179" "00873177" "00873174" ...
## .. ..$ AFFGEOID: chr [1:10] "0500000US33009" "0500000US33011" "0500000US33007" "0500000US33001" ...
## .. ..$ GEOID : chr [1:10] "33009" "33011" "33007" "33001" ...
## .. ..$ NAME : chr [1:10] "Grafton" "Hillsborough" "Coos" "Belknap" ...
## .. ..$ LSAD : chr [1:10] "06" "06" "06" "06" ...
## .. ..$ ALAND : chr [1:10] "4425927252" "2269220216" "4648216798" "1036582289" ...
## .. ..$ AWATER : chr [1:10] "105375486" "41604851" "90773891" "177039345" ...
## ..@ polygons :List of 10
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.8 43.9
## .. .. .. .. .. .. ..@ area : num 0.508
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ plotOrder: int 1
## .. .. .. ..@ labpt : num [1:2] -71.8 43.9
## .. .. .. ..@ ID : chr "685"
## .. .. .. ..@ area : num 0.508
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.7 42.9
## .. .. .. .. .. .. ..@ area : num 0.255
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ ID : chr "866"
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## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.3 44.7
## .. .. .. .. .. .. ..@ area : num 0.539
## .. .. .. .. .. .. ..@ hole : logi FALSE
## .. .. .. .. .. .. ..@ ringDir: int 1
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## .. .. .. ..@ plotOrder: int 1
## .. .. .. ..@ labpt : num [1:2] -71.3 44.7
## .. .. .. ..@ ID : chr "922"
## .. .. .. ..@ area : num 0.539
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.4 43.5
## .. .. .. .. .. .. ..@ area : num 0.136
## .. .. .. .. .. .. ..@ hole : logi FALSE
## .. .. .. .. .. .. ..@ ringDir: int 1
## .. .. .. .. .. .. ..@ coords : num [1:33, 1:2] -71.7 -71.7 -71.7 -71.7 -71.7 ...
## .. .. .. ..@ plotOrder: int 1
## .. .. .. ..@ labpt : num [1:2] -71.4 43.5
## .. .. .. ..@ ID : chr "1100"
## .. .. .. ..@ area : num 0.136
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.1 43
## .. .. .. .. .. .. ..@ area : num 0.208
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ plotOrder: int 1
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## .. .. .. ..@ ID : chr "1278"
## .. .. .. ..@ area : num 0.208
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -72.3 42.9
## .. .. .. .. .. .. ..@ area : num 0.208
## .. .. .. .. .. .. ..@ hole : logi FALSE
## .. .. .. .. .. .. ..@ ringDir: int 1
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## .. .. .. ..@ plotOrder: int 1
## .. .. .. ..@ labpt : num [1:2] -72.3 42.9
## .. .. .. ..@ ID : chr "1877"
## .. .. .. ..@ area : num 0.208
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71 43.3
## .. .. .. .. .. .. ..@ area : num 0.11
## .. .. .. .. .. .. ..@ hole : logi FALSE
## .. .. .. .. .. .. ..@ ringDir: int 1
## .. .. .. .. .. .. ..@ coords : num [1:177, 1:2] -71.2 -71.2 -71.2 -71.2 -71.1 ...
## .. .. .. ..@ plotOrder: int 1
## .. .. .. ..@ labpt : num [1:2] -71 43.3
## .. .. .. ..@ ID : chr "2676"
## .. .. .. ..@ area : num 0.11
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.7 43.3
## .. .. .. .. .. .. ..@ area : num 0.274
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ plotOrder: int 1
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## .. .. .. ..@ ID : chr "2773"
## .. .. .. ..@ area : num 0.274
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
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## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.2 43.9
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## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ ID : chr "3077"
## .. .. .. ..@ area : num 0.288
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -72.2 43.4
## .. .. .. .. .. .. ..@ area : num 0.159
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ plotOrder: int 1
## .. .. .. ..@ labpt : num [1:2] -72.2 43.4
## .. .. .. ..@ ID : chr "3167"
## .. .. .. ..@ area : num 0.159
## ..@ plotOrder : int [1:10] 3 1 9 8 2 6 5 10 4 7
## ..@ bbox : num [1:2, 1:2] -72.6 42.7 -70.7 45.3
## .. ..- attr(*, "dimnames")=List of 2
## .. .. ..$ : chr [1:2] "x" "y"
## .. .. ..$ : chr [1:2] "min" "max"
## ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slot
## .. .. ..@ projargs: chr "+proj=longlat +datum=NAD83 +no_defs"# Check if county names are in the same format in both files
str(nhgeo$NAME)## chr [1:10] "Grafton" "Hillsborough" "Coos" "Belknap" "Rockingham" ...str(nhdata$County)## chr [1:10] "Belknap" "Carroll" "Cheshire" "Coos" "Grafton" "Hillsborough" ...# They're not. Change the county names to plain characters in nhgeo:
nhgeo$NAME <- as.character(nhgeo$NAME)Order each data set by county name
nhgeo <- nhgeo[order(nhgeo$NAME),]
nhdata <- nhdata[order(nhdata$County),]
# Are the two county columns identical now? They should be:
identical(nhgeo$NAME,nhdata$County)## [1] TRUEStep 4: Merge geo data with results data using the merge function
library(sf)
nhmap <- merge(nhgeo, nhdata, by.x = "NAME", by.y = "County")# See the new data structure with
str(nhmap)## Formal class 'SpatialPolygonsDataFrame' [package "sp"] with 5 slots
## ..@ data :'data.frame': 10 obs. of 15 variables:
## .. ..$ NAME : chr [1:10] "Belknap" "Carroll" "Cheshire" "Coos" ...
## .. ..$ STATEFP : chr [1:10] "33" "33" "33" "33" ...
## .. ..$ COUNTYFP : chr [1:10] "001" "003" "005" "007" ...
## .. ..$ COUNTYNS : chr [1:10] "00873174" "00873175" "00873176" "00873177" ...
## .. ..$ AFFGEOID : chr [1:10] "0500000US33001" "0500000US33003" "0500000US33005" "0500000US33007" ...
## .. ..$ GEOID : chr [1:10] "33001" "33003" "33005" "33007" ...
## .. ..$ LSAD : chr [1:10] "06" "06" "06" "06" ...
## .. ..$ ALAND : chr [1:10] "1036582289" "2411458935" "1830366195" "4648216798" ...
## .. ..$ AWATER : chr [1:10] "177039345" "158933434" "57990901" "90773891" ...
## .. ..$ Clinton : num [1:10] 3495 3230 5132 2013 6918 ...
## .. ..$ Sanders : num [1:10] 6005 5638 12441 3639 14245 ...
## .. ..$ SandersMarginVotes : num [1:10] 2510 2408 7309 1626 7327 ...
## .. ..$ SandersPct : num [1:10] 0.632 0.636 0.708 0.644 0.673 ...
## .. ..$ ClintonPct : num [1:10] 0.368 0.364 0.292 0.356 0.327 ...
## .. ..$ SandersMarginPctgPoints: num [1:10] 0.264 0.272 0.416 0.288 0.346 ...
## ..@ polygons :List of 10
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.4 43.5
## .. .. .. .. .. .. ..@ area : num 0.136
## .. .. .. .. .. .. ..@ hole : logi FALSE
## .. .. .. .. .. .. ..@ ringDir: int 1
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## .. .. .. ..@ plotOrder: int 1
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## .. .. .. ..@ ID : chr "1100"
## .. .. .. ..@ area : num 0.136
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.2 43.9
## .. .. .. .. .. .. ..@ area : num 0.288
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ area : num 0.288
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
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## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
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## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
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## .. .. .. ..@ area : num 0.508
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.7 42.9
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## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. .. .. ..@ labpt : num [1:2] -71.7 42.9
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## .. .. .. ..@ area : num 0.255
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.7 43.3
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## .. .. .. .. .. .. ..@ hole : logi FALSE
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## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71.1 43
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## .. .. .. ..@ area : num 0.208
## .. ..$ :Formal class 'Polygons' [package "sp"] with 5 slots
## .. .. .. ..@ Polygons :List of 1
## .. .. .. .. ..$ :Formal class 'Polygon' [package "sp"] with 5 slots
## .. .. .. .. .. .. ..@ labpt : num [1:2] -71 43.3
## .. .. .. .. .. .. ..@ area : num 0.11
## .. .. .. .. .. .. ..@ hole : logi FALSE
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## ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slot
## .. .. ..@ projargs: chr "+proj=longlat +datum=NAD83 +no_defs"Step 5: Create a static map with tmap’s qtm() function:
qtm(nhmap, "SandersMarginVotes")## Some legend labels were too wide. These labels have been resized to 0.62, 0.62, 0.62, 0.57, 0.53. Increase legend.width (argument of tm_layout) to make the legend wider and therefore the labels larger.
qtm(nhmap, "SandersMarginPctgPoints")
For more control over look and feel, use the tm_shape() function:
tm_shape(nhmap) +
tm_fill("SandersMarginVotes", title="Sanders Margin, Total Votes", palette = "PRGn") +
tm_borders(alpha=.5) +
tm_text("NAME", size=0.8)## Warning in sp::proj4string(obj): CRS object has comment, which is lost in output## Some legend labels were too wide. These labels have been resized to 0.62, 0.62, 0.62, 0.57, 0.53. Increase legend.width (argument of tm_layout) to make the legend wider and therefore the labels larger.
Same code as above, but store the static map in a variable, and change the theme to “classic” style:
nhstaticmap <- tm_shape(nhmap) +
tm_fill("SandersMarginVotes", title="Sanders Margin, Total Votes", palette = "viridis") + #I like viridis
tm_borders(alpha=.5) +
tm_text("NAME", size=0.8) +
tm_style("classic")View the map
nhstaticmap## Warning in sp::proj4string(obj): CRS object has comment, which is lost in output## Some legend labels were too wide. These labels have been resized to 0.62, 0.62, 0.62, 0.57, 0.53. Increase legend.width (argument of tm_layout) to make the legend wider and therefore the labels larger.
Save the map to a jpg file with tmap’s tmap_save():
tmap_save(nhstaticmap, filename="nhdemprimary.jpg") ## Warning in sp::proj4string(obj): CRS object has comment, which is lost in output
## Warning in sp::proj4string(obj): CRS object has comment, which is lost in output## Map saved to C:\Users\small\Desktop\MCollege\2021\DATA110\week10\nhdemprimary.jpg## Resolution: 1501.336 by 2937.385 pixels## Size: 5.004452 by 9.791282 inches (300 dpi)Step 6: Create palette and pop-ups for interactive map
Next up: Code for a basic interactive map, this time for Clinton percentages in NH
Create a palette
clintonPalette <- colorNumeric(palette = "Blues", domain=nhmap$ClintonPct)and a pop-up window
library(scales)##
## Attaching package: 'scales'## The following object is masked from 'package:purrr':
##
## discard## The following object is masked from 'package:readr':
##
## col_factorlibrary(raster)
nhpopup <- paste0("County: ", nhmap$County,
"Sanders ", percent(nhmap$SandersPct), " - Clinton ", percent(nhmap$ClintonPct))Step 7: Now generate the interactive map:
# re-project
nhmap_projected <- sp::spTransform(nhmap, "+proj=longlat +datum=WGS84")
leaflet(nhmap_projected) %>%
addProviderTiles("CartoDB.Positron") %>%
addPolygons(stroke=FALSE,
smoothFactor = 0.2,
fillOpacity = .8,
popup=nhpopup,
color= ~clintonPalette(nhmap$ClintonPct)
)South Carolina data
setwd("C:/Users/small/Desktop/MCollege/2021/DATA110/week10/GIS")
scdata <- rio::import(scdatafile)South Carolina shapefile and Quick plot of scgeo SC geospatial object:
scgeo <- usgeo[usgeo@data$STATEFP=="45",]
qtm(scgeo)
Add a column with percent of votes for each candidate. Candidates are in columns 2-7:
candidates <- colnames(scdata[2:7])
for(i in 2:7){
j = i + 7
temp <- scdata[[i]] / scdata$Total
scdata[[j]] <- temp
colnames(scdata)[j] <- paste0(colnames(scdata)[i], "Pct")
}
winner <- colnames(scdata[2:7])Get winner in each precinct
for(i in 1:nrow(scdata)){
scdata$winner[i] <- names(which.max(scdata[i,2:7]))
}Import spreadsheet with percent of adult population holding at least a 4-yr college degree
setwd("C:/Users/small/Desktop/MCollege/2021/DATA110/week10/GIS")
sced <- rio::import("SCdegree.xlsx")Check if county names are in the same format in both files
str(scgeo$NAME)## chr [1:46] "Edgefield" "Lee" "Horry" "Allendale" "Marion" "Dorchester" ...str(scdata$County)## chr [1:46] "Abbeville" "Aiken" "Allendale" "Anderson" "Bamberg" "Barnwell" ...# Change the county names to plain characters in scgeo:
scgeo$NAME <- as.character(scgeo$NAME)
# Order each data set by county name
scgeo <- scgeo[order(scgeo$NAME),]
scdata <- scdata[order(scdata$County),]
# Are the two county columns identical now? They should be:
identical(scgeo$NAME,scdata$County )## [1] TRUEAdd the election results and rename county column
scmap <- merge(scgeo, scdata, by.x = "NAME", by.y = "County") Step 8: Add palettes for a multi-layer map
Instead of just coloring the winner, let’s color by strength of win with multiple layers
# Use same intensity for all - get minimum and maximum for the top 3 combined
minpct <- min(c(scdata$`Donald J TrumpPct`, scdata$`Marco RubioPct`, scdata$`Ted CruzPct`))
maxpct <- max(c(scdata$`Donald J TrumpPct`, scdata$`Marco RubioPct`, scdata$`Ted CruzPct`))Create leaflet palettes for each layer of the map:
trumpPalette <- colorNumeric(palette = "Purples", domain=c(minpct, maxpct))
rubioPalette <- colorNumeric(palette = "Reds", domain = c(minpct, maxpct))
cruzPalette <- colorNumeric(palette = "Oranges", domain = c(minpct, maxpct))
winnerPalette <- colorFactor(palette=c("#984ea3", "#e41a1c"), domain = scmap$winner)
edPalette <- colorNumeric(palette = "Blues", domain=scmap$PctCollegeDegree)Create a pop-up:
scpopup <- paste0("<b>County: ", scmap$County, "<br />Winner: ", scmap$winner, "</b><br /><br />Trump: ", percent(scmap$`Donald J TrumpPct`), "<br />Rubio: ", percent(scmap$`Marco RubioPct`), "<br />Cruz: ", percent(scmap$`Ted CruzPct`), "<br /><br />Pct w college ed: ", sced$PctCollegeDegree, "% vs state-wide avg of 25%")Add the projection we know from the NH map we’ll need for this data on a Leaflet map:
scmap <- sp::spTransform(scmap, "+proj=longlat +datum=WGS84")Basic interactive map showing winner in each county:
leaflet(scmap) %>%
addProviderTiles("CartoDB.Positron") %>%
addPolygons(stroke=TRUE,
weight=1,
smoothFactor = 0.2,
fillOpacity = .75,
popup=scpopup,
color= ~winnerPalette(scmap$winner),
group="Winners" ) %>%
addLegend(position="bottomleft", colors=c("#984ea3", "#e41a1c"), labels=c("Trump", "Rubio"))Step 9: Add map layers and controls
Put top 3 candidates in their own layers and add education layer, store in scGOPmap2 variable
scGOPmap <- leaflet(scmap) %>%
addProviderTiles("CartoDB.Positron") %>%
addPolygons(stroke=TRUE,
weight=1,
smoothFactor = 0.2,
fillOpacity = .75,
popup=scpopup,
color= ~winnerPalette(scmap$winner),
group="Winners" ) %>%
addLegend(position="bottomleft", colors=c("#984ea3", "#e41a1c"), labels=c("Trump", "Rubio")) %>%
addPolygons(stroke=TRUE,
weight=1,
smoothFactor = 0.2,
fillOpacity = .75,
popup=scpopup,
color= ~trumpPalette(scmap$`Donald J TrumpPct`),
group="Trump") %>%
addPolygons(stroke=TRUE,
weight=1,
smoothFactor = 0.2,
fillOpacity = .75,
popup=scpopup,
color= ~rubioPalette(scmap$`Marco RubioPct`),
group="Rubio") %>%
addPolygons(stroke=TRUE,
weight=1,
smoothFactor = 0.2,
fillOpacity = .75,
popup=scpopup,
color= ~cruzPalette(scmap$`Ted CruzPct`),
group="Cruz") %>%
addPolygons(stroke=TRUE,
weight=1,
smoothFactor = 0.2,
fillOpacity = .75,
popup=scpopup,
color= ~edPalette(sced$PctCollegeDegree), #this data is in the sced table, not scmaps
group="College degs") %>%
addLayersControl(
baseGroups=c("Winners", "Trump", "Rubio", "Cruz", "College degs"),
position = "bottomleft",
options = layersControlOptions(collapsed = FALSE))
# Now display the map
scGOPmapStep 10: Save your interactive map
Save as a self-contained HTML file
#htmlwidgets::saveWidget(scGOPmap2, file="scGOPwidget2.html")
# save as an HTML file with dependencies in another directory:
#htmlwidgets::saveWidget(widget=scGOPmap2, file="scGOPprimary_withdependencies.html", selfcontained=FALSE, libdir = "js")