Point-to-grid gis.stackexchange

# For illustrative purpose plot the points on a map
# Load suitable library and plot the area of interest.
library(rworldmap)
newmap <- getMap(resolution = "high")

# Plot refined to Africa
plot(newmap,
     xlim = c(-25,60),
     ylim = c(-35, 37),
     asp = 1)

# A more accurate plot can be get by using the extreme points of the continent
library(ggmap)
africa.limits <- geocode(c("Iles des Chiens, Tunisia",
                           "Cape Agulhas, South Africa",
                           "Santa Antão, Cape Verde Islands",
                           "Rodrigues, Mauritius")
)
africa.limits

plot(newmap,
     xlim = range(africa.limits$lon),
     ylim = range(africa.limits$lat),
     asp = 1
)

# Import the customised ACLED dataset
acled<-read.csv("/home/R/acled_1997-2011.csv", header=TRUE)
head(acled)

# Plot the points on the map
points(acled$lon,acled$lat,col="red",cex=0.3)

# Load shapefile with the 1x1 degree grid
library("sp")
library("rgdal")
# Set the correct working directory
setwd("/home/R/Shapefiles")
# Check layers
ogrListLayers("ne_10m_graticules_1.shp")
# Load the shapefile
shape<-readOGR(dsn="/home/R/Shapefiles",layer="ne_10m_graticules_1")
plot(shape,add=TRUE)

# TODO: Aggregate points-to-grid