how to efficiently import multiple raster (.tif) files into R
Solution 1
if the rasters have the same extent you can simply load them in a stack
#first import all files in a single folder as a list
rastlist <- list.files(path = "/path/to/wd", pattern='.TIF$', all.files=TRUE, full.names=FALSE)
library(raster)
allrasters <- stack(rastlist)
Solution 2
I found the answer and will post the full code to help other beginner R-users who have this issue. To call a list element, use double square brackets [[]], like this:
#first import all files in a single folder as a list
rastlist <- list.files(path = "/path/to/wd", pattern='.TIF$',
all.files=TRUE, full.names=FALSE)
#import all raster files in folder using lapply
allrasters <- lapply(rastlist, raster)
#to check the index numbers of all imported raster list elements
allrasters
#call single raster element
allrasters[[1]]
#to run a function on an individual raster e.g., plot
plot(allrasters[[1]])
Booyah. Thanks to Parfait for help.
Dorothy
Updated on June 07, 2022Comments
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Dorothy almost 2 years
I am an R novice, especially when it comes to spatial data. I am trying to find a way to efficiently import multiple (~600) single-band raster (.tif) files into R, all stored in the same folder. Not sure if this matters but note that, when viewed in a folder on my Mac and Windows Parallel VM, there are the following five (5) file formats for each .tif = .TIF; .tfw; .TIF.aux.xml; .TIF.ovr; .TIF.xml. At any rate, the following code (and other similar variants I've tried) does not seem to work:
library(sp) library(rgdal) library(raster) #path to where all .tif files are located setwd("/path/to/workingdirectory") #my attempt to create a list of my .tif files for lapply temp = list.files(pattern="*.tif") temp #returns 'character(0)' #trying to use the raster function to read all .tif files myfiles = lapply(temp, raster) myfiles #returns 'list()'
Is there a way to use some form of loop to import all raster files efficiently?