stack{raster} of n Raster Layers

Question

I have a question about stack() Raster Layers.

Usually I stack() Raster Layers like that:

stack(RasterLayer1,RasterLayer2,RasterLayer3) # e.g. for 3 Layers

My Question is, how can I stack() Raster Layers without typing in every Raster Layer?

For example: n is the amount of Raster Layers (e.g. 12), all named band.

I created n-Raster Layers and now I want to stack all without typing n-times the Name of the Raster Layers. So instead of typing:

stack(band1,band2,band3,band4,band5,band6,band7,band8,band9,band10,band11,band12)

I want to short that by stack(band[n]), but that doesn't work.

And if I create a list of all bands, I can't stack that list, because they don't appear in my Working Directory because I just created them.

Can anyone help me, please?

Answer 1

If your data is in a directory, you can use a search pattern (for example: *.tif, *.grd,...) and store it in a variable.

bands <- list.files(path=".",pattern="*.tif",full.names=TRUE,recursive=TRUE)

now assume that your data is called:

band_01.tif
band_02.tif
band_03.tif
band_04.tif
band_05.tif
band_06.tif
band_07.tif

then you can stack for example:

data_stack <- stack(bands) #stack all data
data_stack <- stack(bands[1:3]) #stack 1,2 and 3 data
data_stack <- stack(bands[c(1,3,5,7)]) 

Answer 2

I would recommend not to save them under separate variables like band1,band2,... but instead store them in a list. Here an example:

#Create empty rasters
ras1<- raster()
ras2<- raster()

#Initialise and append to list
list_ras <- list()
list_ras[[1]] <- ras1
list_ras[[2]] <- ras2

#Stack single bands
ras_stack <- stack(list_ras[[1]], list_ras[[2]])

#Stack all bands
ras_stack <- stack(list_ras)