Building small multiples with a for loop in R

Question

I'm trying to build a map with small multiples that shows hurricanes / tropical storms that intersected with Florida since 1900. I used some spatial queries to subset the database of all Atlantic storms for this project.

Now I draw a shapefile line of my limited number of hurricane tracks on top of Florida state polygons, some adjacent states, several major cities in Florida, and, of course, Lake Okeechobee. Here is a simple code:

library(maptools)
library(gdata)
library(RColorBrewer)

setwd("~/hurricanes")

# read shapefiles
florida <- readShapePoly("florida.shp")
south <- readShapePoly("south.shp")
hurricanes <- readShapeLines("hurricanes-florida.shp")

cities <- readShapePoints("cities.shp")
lakes <- readShapePoly("lakes.shp")

# miami, orlando and tallahassee (in FL)
cities <- subset(cities, ST == "FL")

# don't need ALL the 'canes
hurricanes1900 <- subset(hurricanes, Season >= 1900)

mycolors <- brewer.pal(5, "YlOrRd")

pdf(file = "hurricanemaps.pdf", ,width=8,height=20)
    par(mfrow=c(15,5), mar=c(1,1,1,1))
    for(i in 1:nrow(hurricanes1900)) 
        { 
        plot(south, col="#e6e6e6", border = "#999999")
        plot(florida, col="#999999", border = "#999999", add = TRUE)
        plot(lakes, col="#ffffff", border = "#999999", add = TRUE)
        plot(cities, pch=10, cex=.1,col="#000000", bg="#e38d2c", lwd=1, add = TRUE)
        plot(hurricanes1900[i,], col = mycolors[cut(hurricanes$MAX_Wind_W, breaks = 5)],
             lwd=3, add = TRUE); title(hurricanes1900$Title[i])
     }
dev.off()

Three big questions I come across:

1) The cycle gives me a map of each storm. I would prefer the code to produce a Florida / South map in the grid for each year (even in those years without storms) and all the storms for that year, preferably with labels.

2) , . , ( 1992 ) , . , (H1, H2 ..) , .

3) , № 1, . maptools .

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Answer 1

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library(stringi)
library(tibble)
library(raster)
library(ggplot2)
library(ggthemes)
library(ggrepel)
library(RColorBrewer)
library(data.table)

# Get some data. Credit to hmbrmstr for a few lines in the following code.

mylist <- c("http://weather.unisys.com/hurricane/atlantic/2007H/BARRY/track.dat",
            "http://weather.unisys.com/hurricane/atlantic/2007H/TEN/track.dat",
            "http://weather.unisys.com/hurricane/atlantic/2006H/ERNESTO/track.dat",
            "http://weather.unisys.com/hurricane/atlantic/2006H/ALBERTO/track.dat")

temp <- rbindlist(
            lapply(mylist, function(x){
                foo <- readLines(x)
                foo <- read.table(textConnection(gsub("TROPICAL ", "TROPICAL_",
                                  foo[3:length(foo)])), 
                                  header=TRUE, stringsAsFactors=FALSE)

                year <- stri_extract_first(str = x, regex = "[0-9]+")
                name <- stri_extract_first(str = x, regex = "[A-Z]{2,}")

                cbind(foo, year, name)

            }
        ))


### Add a fake row for 2017
temp <- temp %>%
        add_row(ADV = NA, LAT = NA, LON = NA, TIME = NA, WIND = NA,
                PR = NA, STAT = NA, year = 2017, name = NA)

### Prepare a map
usa <- getData('GADM', country = "usa", level = 1)
mymap <- subset(usa, NAME_1 %in% c("Florida", "Arkansas", "Louisiana",
                                   "Alabama", "Georgia", "Tennessee",
                                   "Mississippi",
                                   "North Carolina", "South Carolina"))
mymap <- fortify(mymap)


# Create a data.table for labeling hurricanes later.
label <- temp[, .SD[1], by = name][complete.cases(name)]

g <- ggplot() +
     geom_map(data = mymap, map = mymap,
              aes(x = long, y = lat, group = group, map_id = id),
                  color = "black", size = 0.2, fill = "white") +
    geom_path(data = temp, aes(x = LON, y = LAT, group = name, color = WIND), size = 1) +
    scale_color_gradientn(colours = rev(brewer.pal(5, "Spectral")), name = "Wind (mph)") +
    facet_wrap(~ year) +
    coord_map() +
    theme_map() +
    geom_text_repel(data = label,
                    aes(x = LON, y = LAT, label = name),
                    size = 2, 
                    force = 1,
                    max.iter = 2e3,
                    nudge_x = 1,
                    nudge_y = -1) +
    theme(legend.position = "right")