Back again with more questions. :)
As per suggestions on a previous question of mine, I have decided to try to transform my ongoing map project/test to
ggplot2 for ease of use. You can check out my full original non-ggplot code here if you're into that kind of thing. I have done a tiny bit of mapping with
ggplot2 in the past, so I'm kinda-sorta familiar with it, but I've certainly not mastered it. I'm wondering how to change/customize my color scheme for the
ML1 attributes of my Ethiopia polygon. It should look like this (which I did with base plot functions, as seen in my linked code):
Using this brief tutorial from GitHub, I managed to finagle with my code a bit to create this:
library(ggplot2) library(maptools) library(rgdal) library(rgeos) library(raster) library(plyr) setwd("D:/Mapping-R/Ethiopia") ea.ml1 <- readOGR(dsn = "D:/Mapping-R/Ethiopia", layer = "EA201507_ML1") eth <- readOGR(dsn = "D:/Mapping-R/Ethiopia", layer = "ETH_adm0") #remove all unwanted columns from eth shapefile eth <- eth[, -(2:67)] #define color scheme for ml1 & ml2 features ea.ml1@data$COLOR[ea.ml1@data$ML1 == 1] <- "gray" ea.ml1@data$COLOR[ea.ml1@data$ML1 == 2] <- "yellow" ea.ml1@data$COLOR[ea.ml1@data$ML1 == 3] <- "orange" ea.ml1@data$COLOR[ea.ml1@data$ML1 == 4] <- "red" #clip ethiopia to ml1 background eth.clip1 <- intersect(ea.ml1, eth) #identifies attribute rows, converts to data frame, joins points to attributes eth.clip1@data$id <- rownames(eth.clip1@data) eth.f <- fortify(eth.clip1, region = "id") eth.df <- join(eth.f, eth.clip1@data, by = "id") ggplot(eth.df) + aes(long, lat, group = group, fill = ML1) + geom_polygon() + geom_path(color="white") + coord_equal()
How do I customize my
ggplot2 color scheme (which is actually defined in the code, not sure if that's useful or not) to match the first map image that I posted (where an ML value of 1 is gray, 2 is yellow, etc.)? The linked tutorial simply lists its color scheme as "Utah Ecoregion" with no details about where it came from/what it looks like. I also tried the solution listed here to no avail; R just spit nonsensical errors at me.
ggplot(eth.df) + aes(long, lat, group = group, fill = ML1) + geom_polygon() + scale_fill_manual(values = (1 = "gray", 2 = "yellow", 3 = "orange", 4 = "red")) + geom_path(color="white") + coord_equal()
gives me these errors:
Error: unexpected ',' in: " geom_polygon() + scale_fill_manual(values = (1 = "gray","
Error in geom_path(color = "white") + coord_equal() : non-numeric argument to binary operator`
So, how do I customize the color scheme without screwing everything else up?