A similar question has been asked before, but for adding data from different columns of one data frame to the plot. Link to the question
In my case, I would like to add new map layers, if they exist in the global environment, to my final map with a "for" loop.
With the code as it is now, only the final layer, the points, is plotted to the map, but not the line layer:
rm(list = ls())
library(OpenStreetMap)
library(ggplot2)
library(sp)
### The base layer map
map <- OpenStreetMap::openmap(c(55.8759, -4.2946), c(55.8638, -4.2776), type="osm")
map <- openproj(map)
myMap <- ggplot2::autoplot(map)
### Create some custom map files
# Some spatial point
new_shapefile <- data.frame(long = -4.290, lat = c(55.868, 55.872))
sp::coordinates(new_shapefile) <- c("long", "lat")
sp::proj4string(new_shapefile) <- sp::CRS("+init=epsg:4326")
# Some spatial line
x <- c(-4.290,-4.285)
y <- c(55.868,55.868)
new_line <- SpatialLines(list(Lines(Line(cbind(x,y)), ID="a")))
new_line = SpatialLinesDataFrame(new_line, data.frame(Z = c("Road"), row.names = c("a")))
addLayer <- function(){
glob <- globalenv()
customFiles <- data.frame(ls(pattern = "^(?i)new", envir = glob))
colnames(customFiles) <- "X"
customFiles$X <- as.character(customFiles$X)
for(i in 1:length(customFiles$X)){
plot <- myMap
gg.data <- get(paste(customFiles$X[i]))
if(grepl("^SpatialPolygons", class(get(paste(customFiles$X[i])))) == TRUE){
plot <- plot + geom_polygon(data = gg.data, aes(long, lat, group= group))
}
if(grepl("^SpatialLines", class(get(paste(customFiles$X[i])))) == TRUE){
plot <- plot + geom_path(data = gg.data, aes(long, lat, group= group))
}
if(grepl("^SpatialPoints", class(get(paste(customFiles$X[i])))) == TRUE){
plot <- plot + geom_point(data = data.frame(coordinates(gg.data)), aes(long, lat))
}
}
print(plot)
}
### Run the function
addLayer()
Since I can't use melt to solve this, as suggested in the previous question: Is there any other way to plot all of the layers in the "for" loop?
plotin each iteration of the loop. You probably want to initiate the plot,plot <- myMap, just before you start the loop. It looks like "gg.data" in eachifstatement also will need work. In the points layer you turn this into a data.frame so that layer works fine, but you use "gg.data" directly in the other layers and it doesn't appear to be a data.frame.plot <- myMapbefore the "for" loop actually solved it!! I turned only the points layer into a data.frame, since it otherwise gave me an error:ggplot2 doesn't know how to deal with data of class SpatialPoints