75 lines
2.2 KiB
R
75 lines
2.2 KiB
R
#install.packages("raster")
|
|
#install.packages("rgdal")
|
|
library(raster)
|
|
library(rgdal)
|
|
|
|
#Assign .tif to an object
|
|
dem <- raster("SRTM_ffB01_p045r032.tif")
|
|
|
|
#General information
|
|
summary(dem)
|
|
|
|
#Structure of an object
|
|
str(dem)
|
|
|
|
#Visualize the imagery
|
|
plot(dem)
|
|
##Set min and max value
|
|
plot(dem, zlim=c(0,3000))
|
|
##Change color schemes (greyscale)
|
|
plot(dem, zlim=c(0,3000), col=grey.colors(255))
|
|
##Change color schemes (terrain colors)
|
|
plot(dem, zlim=c(0,3000), col=terrain.colors(255))
|
|
|
|
#Derive terrain features such as slope and aspect
|
|
slp <- terrain(dem, opt="slope", unit="degrees")
|
|
slp <- terrain(dem, opt="aspect", unit="degrees")
|
|
|
|
#Read single raster bands
|
|
blue2011 <- raster ("./LT05_L1TP_045032_20110909_20160831_01_T1/LT05_L1TP_045032_20110909_20160831_01_T1_B1.TIF")
|
|
green2011 <- raster ("./LT05_L1TP_045032_20110909_20160831_01_T1/LT05_L1TP_045032_20110909_20160831_01_T1_B2.TIF")
|
|
red2011 <- raster ("./LT05_L1TP_045032_20110909_20160831_01_T1/LT05_L1TP_045032_20110909_20160831_01_T1_B3.TIF")
|
|
nir2011 <- raster ("./LT05_L1TP_045032_20110909_20160831_01_T1/LT05_L1TP_045032_20110909_20160831_01_T1_B4.TIF")
|
|
swira2011 <- raster ("./LT05_L1TP_045032_20110909_20160831_01_T1/LT05_L1TP_045032_20110909_20160831_01_T1_B5.TIF")
|
|
swirb2011 <- raster ("./LT05_L1TP_045032_20110909_20160831_01_T1/LT05_L1TP_045032_20110909_20160831_01_T1_B7.TIF")
|
|
|
|
#Multiband raster
|
|
ls52011 <- stack(blue2011,green2011,red2011,nir2011,swira2011,swirb2011)
|
|
|
|
#Plot multiband raster images
|
|
plot(ls52011)
|
|
plot(ls52011[[4]]) #only one layer
|
|
plotRGB(ls52011, 3, 2, 1, stretch="lin") #plot RGB
|
|
|
|
#Raster image information
|
|
res (ls52011) #Resulution
|
|
projection (ls52011) #Projection
|
|
dim (ls52011) #Dimention (rows & columns)
|
|
nlayers (ls52011) #Number of layers
|
|
extent (ls52011)
|
|
ncell (ls52011)
|
|
|
|
#Display new extent (crop) with lines on a plot
|
|
plot(nir2011)
|
|
abline(v=510000)
|
|
abline(v=580000)
|
|
abline(h=4490000)
|
|
abline(h=4543000)
|
|
|
|
#Define new extent (crop) with a box on a plot
|
|
plot(nir2011)
|
|
e <- extent(510000, 580000, 4490000, 4543000)
|
|
plot(e, add=TRUE, col = "red")
|
|
|
|
#Crop the image
|
|
ls52011.subs <- crop(ls52011, e)
|
|
##plot
|
|
plotRGB (ls52011.subs, 3, 2, 1, stretch="lin")
|
|
|
|
#Homework
|
|
dim(ls52011.subs)
|
|
ncell(ls52011.subs)
|
|
extent(ls52011)
|
|
636315-395685
|
|
4571415 - 4355985
|
|
215.430 * 240.630 |