CODEWITHSUNDEEP
rplotraster
user9563072
user9563072

Reputation:

Plotting raster with thresholds in R

I want to plot population data. The data is raster data. The map should have red areas where less than 1 person lives, and another color for areas with more than one person. If I just use the plot() function I cannot achieve it. My data comes from: http://sedac.ciesin.columbia.edu/data/set/gpw-v4-population-count-rev10 Any idea how to solve the problem?

Upvotes: 1

Views: 1224

Answers (2)

SeGa
SeGa

Reputation: 9809

There are many similar questions like that and a lot of answers, but maybe these 2 options might help.

library(raster)

## Create random raster
spg <- data.frame( x = rep( 0:1, each=2 ),
                  y = rep( 0:1,  2),
                  l = c(0.8,1,1.1,100));
coordinates(spg) <- ~ x + y
gridded(spg) <- TRUE
rasterDF <- raster(spg)

## Assign values, based on your condition
values(rasterDF) <- as.numeric(values(rasterDF) >= 1)

## Create a Color Function
cpal <- colorRampPalette(c("red", "blue"))

## Plot with raster-package
plot(rasterDF, col=cpal(2))

## Plot with rasterVis package
library(rasterVis)
r2 <- ratify(rasterDF)
levelplot(r2, col.regions=cpal, att='ID')

Upvotes: 2

user387832
user387832

Reputation: 503

How about this:

library(raster)

myColorRamp <- colorRampPalette(c("red", "blue"))

popRaster <- raster("path/to/my/raster")

values(popRaster) <- as.numeric(values(popRaster) >= 1)

plot(popRaster, col=myColorRamp(2))

You need to install the raster package, which I believe has the sp package as a dependency (and possibly rgdal).

Upvotes: 2

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