Basic methods for dealing with shapefiles for marine ecoregions of the world.

meow_plot_base.R

#########################################################################
# Code to import and make useful
# Spalding et al. 2007's Marine Ecoregions of the World
# Data provided by http://www.marineregions.org/downloads.php
# by Jarrett Byrnes
# last updated 3/26/2015
#########################################################################

######################
##### Load Libraries
######################
#for visualization
library(ggmap)
library(ggplot2)
library(RColorBrewer)

#for some data reduction
library(dplyr)

#for geospatial tools
library(rgdal)
library(maptools)
library(rgeos)

#Let's see what's in this shapefile!
ogrInfo("../../MEOW-TNC", "meow_ecos")

#get an ecoregions shapefile, and from that make a provience and realm shapefile
#from http://www.marineregions.org/downloads.php
#http://www.marineregions.org/sources.php#meow
regions <- readOGR("../../MEOW-TNC", "meow_ecos")

######
#Make Provinces shapefile
######
#Unite the spatial polygons for each region into one
provinces <- unionSpatialPolygons(regions, regions$PROVINCE)

#Make a data frame that will have Province level info and above
prov_data <- regions@data %>%
  group_by(PROVINCE) %>%
  summarise(PROV_CODE = PROV_CODE[1], REALM = REALM[1], RLM_CODE=RLM_CODE[1], Lat_Zone=Lat_Zone[1])

#merge the polygons with the new data file
#note the row.names argument to make sure they map to each other
provinces <- SpatialPolygonsDataFrame(provinces, 
                                      data=data.frame(join(data.frame(PROVINCE=names(provinces)),
                                                           prov_data),
                                                      row.names=row.names(provinces)))
#######
#make realms shapefile
########
#make spatial polygons for realms
realms <- unionSpatialPolygons(regions, regions$REALM)

#make new data
realm_data <- regions@data %>%
  group_by(REALM) %>%
  summarise(RLM_CODE = RLM_CODE[1],  Lat_Zone=Lat_Zone[1])

#merge the two!
realms <- SpatialPolygonsDataFrame(realms, 
                                   data=data.frame(join(data.frame(REALM=names(realms)),
                                                        realm_data),
                                                   row.names=row.names(realms)))

#########Plot them all
par(mfrow=c(2,2), mar=c(0,0,0,0))
plot(regions, main="Ecoregion", cex.main=5)
plot(provinces, lwd=2, border="red", main="Province")
plot(realms, lwd=2, border="blue", main="Realm")
par(mfrow=c(1,1))

##########
#OK - let's make some data frames
# so we can use ggplot2 and other tools
##########

#Turn SpatialPolygons into data frames
#from https://github.com/hadley/ggplot2/wiki/plotting-polygon-shapefiles
regions@data$id = rownames(regions@data)
regions.points = fortify(regions, ECOREGION="id")
regions.df = join(regions.points, regions@data, by="id")

#now do it for provinces
provinces@data$id = rownames(provinces@data)
provinces.points = fortify(provinces, PROVINCES="id")
provinces.df = join(provinces.points, provinces@data, by="id")

#####Make some ggplots for later visualization
base_ecoregion_ggplot <- ggplot(regions.df) + theme_bw() +
  aes(long,lat,group=group) + 
  geom_polygon(fill=NA) +
  geom_path(color="black") +
  coord_equal() 


base_province_ggplot <- ggplot(provinces.df) + theme_bw() +
  aes(long,lat,group=group) + 
  geom_polygon(fill=NA) +
  geom_path(color="black") +
  coord_equal() 

#############
# Show how filling works
#############

#let's make some fancy colors
library(RColorBrewer)

#Make a data frame with Ecoregion as an identifier
thing <- data.frame(ECOREGION = regions$ECOREGION,
                    score = runif(nrow(regions), -100, 100))

#merge the score data with the regions data frame
regions.df2 <- merge(regions.df, thing)

#plot!
ggplot(regions.df2) + theme_bw() +
       aes(long,lat,group=group) + 
       geom_polygon(mapping=aes(fill=score)) +
       geom_path(color="black") +
       coord_equal() +
       scale_fill_gradientn(colours=brewer.pal(11, "Spectral"))
  

Yup, I found it to with the same search terms!

Hi. I have grouped certain ecoregions and I want to give specific colors to each group. Do you know how I can do it?