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I have 365 rasters (daily_sm2rain data of a year) in .TIF. I would like to create a new raster which is sum of 365 input rasters in R (~ sum of rain in a year). How can I do this?

I tried input=list.files("path_to_data",pattern="*.tif$"). it's ok.

map <- brick(paste0("path_to_data",input[1])) fives:

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

print(input)
    [1] "daily.rainfall_2018-01-02_10km.tif" "daily.rainfall_2018-01-03_10km.tif"
      [3] "daily.rainfall_2018-01-04_10km.tif" "daily.rainfall_2018-01-05_10km.tif"
      [5] "daily.rainfall_2018-01-06_10km.tif" "daily.rainfall_2018-01-07_10km.tif"
      [7] "daily.rainfall_2018-01-08_10km.tif" "daily.rainfall_2018-01-09_10km.tif"
      [9] "daily.rainfall_2018-01-10_10km.tif" "daily.rainfall_2018-01-11_10km.tif"
     [11] "daily.rainfall_2018-01-12_10km.tif" "daily.rainfall_2018-01-13_10km.tif"
     [13] "daily.rainfall_2018-01-14_10km.tif" "daily.rainfall_2018-01-15_10km.tif
....
361 rows.
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  • Whats the final goal, plot them of writing them to a file?
    – Chelmy88
    Aug 17, 2019 at 10:07
  • 1
    Do you know how to read in one raster file? Please show some code so we know where to start.
    – Spacedman
    Aug 17, 2019 at 12:56
  • See my answere. Does it work for you?
    – Chelmy88
    Aug 17, 2019 at 23:44
  • What do you obtain by just running paste0("path_to_data",input[1])?
    – Chelmy88
    Aug 19, 2019 at 11:07

2 Answers 2

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9

So close, use:

files = list.files("path_to_data",pattern="*.tif$", full.names=TRUE)

rs <- brick(files)

or

rs <- stack(files)

Don't use map as name, there're several R functions with the same name.

Then, to create a sum of all your rasters use calc function (from raster package):

rs1 <- calc(rs, sum)
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2
  • Thanks aldo_tapia so much. It worked.
    – quoc-non duong
    Aug 19, 2019 at 14:49
  • You're welcome. You can accept the answer if you want, closing this topic
    – aldo_tapia
    Aug 19, 2019 at 15:03
2

You can read the raster in R with the rasterpackage.

It can be loaded with map <- brick("file_path"). Then you can apply addition operation between your loaded objects. If you have 365 of them, you should read them through a loop.

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  • Thank Chelmy88 so much. Please give me some details about "through a loop" in R (functions or commands, advanced packages....).
    – quoc-non duong
    Aug 19, 2019 at 1:28
  • What is your knowledge in R? I can show you an example, I would need to know how your files are called then
    – Chelmy88
    Aug 19, 2019 at 7:22
  • Hi Chelmy88, I am quite new to R. I tried rasterstack [# input=list.flies("path_to_data",pattern="*.tif$") # stack=raster::stack(input)]. But it didn't work.
    – quoc-non duong
    Aug 19, 2019 at 8:42
  • Error in .local(.Object, ...) : Error in .rasterObjectFromFile(x, band = band, objecttype = "RasterLayer", : Cannot create a RasterLayer object from this file. (file does not exist)
    – quoc-non duong
    Aug 19, 2019 at 8:48
  • Should be list.files and not list.flies, then try map <- brick(paste0("path_to_data",input[1])). What do you get. And what do you get with print(input)after running list.files (do not hesitate to add it to your question, it is more readable than in comments).
    – Chelmy88
    Aug 19, 2019 at 9:05

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