I want to create a value distribution chart, like a histogram or graph, of a raster image using:
library(raster)
library(sp)
library(rgdal)
DEM <- raster("NR.tif")
hist(DEM)
plot(DEM)
plot()
is used to validate my data and shows me an all green image. Supposedly band 1 of 3.
However I can't see other bands?
Obviously the distribution in the histogram doesn't represent interpolated values in the imagefile.
A histogram created in ARCgis is herehist, which I believe represent the true values.
Any suggestions on how to create a histogram of the real values like the image.
Best, Mathias
You could try
download.file("https://www.dropbox.com/s/t279m5ojners7fl/NR.tif?dl=1",
tf <- tempfile(fileext = ".tif"), mode="wb")
library(raster)
library(tiff)
library(ggplot2)
library(reshape2)
DEM <- readTIFF(tf)
plot(as.raster(DEM))
ggplot(melt(DEM),
aes(value, fill=as.factor(Var3))) +
geom_histogram(position="dodge")
Or, with regards to your update
r <- as.raster(DEM)
tab <- as.data.frame(sort(table(r)))
ggplot(subset(tab, !r %in% c("#F0F0F0", "#000000")),
aes(x=r, y=Freq, fill=I(r))) +
geom_bar(stat="identity") +
theme(axis.text.x = element_text(angle=90))