R error in renaming list of objects

Question

I am working with R 3.4.0.

I have got multiple single-band rasters, gathered in one folder, which I want to stack together, in a multi-band raster. Following the instructions of other posts, I wrote these simple lines:

s2_list <- list.files(path="C:/Users/LAURA/Documents/S2", pattern=".tif$")
s2_stack <- stack(s2_list)

This procedure gave me the following error:

Error in .local(.Object, ...) :
Error in .rasterObjectFromFile(x, band = band, objecttype = "RasterLayer", : Cannot create a RasterLayer object from this file. (file does not exist)

I read other posts with the same problem but without a clear solution; one of the alternatives is renaming the files of the list, which I'm trying to do with the following script:

s2_list <- list.files(path="C:/Users/LAURA/Documents/S2", pattern=".tif$")
names_list <- paste("ndvi_", 1:104)
file.rename(s2_list, names_list)
s2_stack <- stack(s2_list)

The output is the following:

file.rename(s2_list, names_list)

[1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[20] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[39] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[58] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[77] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[96] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE

Anyone has got any idea why this happens? I already checked the number of objects in the first list, and it's 104.

Sample of s2_list:

s2_list
  [1] "S2A_20150706T105351Z_31UFS_NDVI_10M_V008.tif" "S2A_20150716T105024Z_31UFS_NDVI_10M_V008.tif"
  [3] "S2A_20150726T105024Z_31UFS_NDVI_10M_V008.tif" "S2A_20150805T105026Z_31UFS_NDVI_10M_V008.tif"
  [5] "S2A_20150812T104021Z_31UFS_NDVI_10M_V008.tif" "S2A_20150815T105627Z_31UFS_NDVI_10M_V008.tif"
  [7] "S2A_20150822T104035Z_31UFS_NDVI_10M_V008.tif" "S2A_20150825T105041Z_31UFS_NDVI_10M_V008.tif"
  [9] "S2A_20150904T105042Z_31UFS_NDVI_10M_V008.tif" "S2A_20150911T104038Z_31UFS_NDVI_10M_V008.tif"

You probably need to use the full.names argument: s2_list <- list.files(path="C:/Users/LAURA/Documents/S2", pattern=".tif$", full.names=TRUE) — lmo
– lmo, Commented Jun 8, 2017 at 12:27
also in names_list <- paste("ndvi_", 1:104) you might need the full path as well : ergo. paste("C:/Users/LAURA/Documents/S2/ndvi_", 1:104) — amonk
– amonk, Commented Jun 8, 2017 at 12:30
I tried and I get an interesting result: the first 6 objects are 'FALSE', while the rest of the objects in the list is 'TRUE. So, R has renamed only one part of the rasters... — Laura Paladini
– Laura Paladini, Commented Jun 8, 2017 at 12:41
sorry, I forgot to close those 6 files in QGIS. Now it works! — Laura Paladini
– Laura Paladini, Commented Jun 8, 2017 at 12:42

amonk · Accepted Answer · 2017-06-08 14:05:03Z

0

A more safe way is to avoid "hard coding" (<- root of all evil) .

    targetDir<-file.path("path","where","your","files","reside")
    s2_list <-list.files(path=targetDir,pattern=".tif$",full.names = T) 
    names_list <- paste0(targetDir,"/ndvi_", 1:length(s2_list),".tif")
    file.rename(s2_list, names_list)

answered Jun 8, 2017 at 14:05

amonk

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2 Comments

Laura Paladini Over a year ago

Thank you for your answer. Does this function rename the files in the folder or only the files in the R environment? I haven't got permission to rename the files or write in the folder where the files are located.

amonk Over a year ago

@LauraPaladini If you don't have permissions, then R won't be able to help :) So I would suggest you found a path where you can mkdir (e.g.)

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