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rimportasciiraster

R - raster function NAs values lower than -9999 in ASCII file

I have been having problems importing a ASCII raster that has values that go from Min. :-69826220 to Max. :167780500. The problem I am encountering is that when I use the raster function to import the ASCII file then every value smaller than -9999 is reported as NA and the minimum value is -9458.

Is this a bug of the function and is there a workaround? When I import the same ASCII file as a data frame everything is fine and I get the whole range of values. Also I am using the same procedure to import other ASCII rasters and don't have any problem.

here is the link to the ASCII file https://dl.dropboxusercontent.com/u/24234831/ps0011yme.asc

Here is the session info, I opened a new session just in case.

sessionInfo() R version 3.0.0 (2013-04-03) Platform: x86_64-w64-mingw32/x64 (64-bit)

locale: [1] LC_COLLATE=English_United States.1252 [2] LC_CTYPE=English_United States.1252
[3] LC_MONETARY=English_United States.1252 [4] LC_NUMERIC=C
[5] LC_TIME=English_United States.1252

attached base packages: [1] stats graphics grDevices utils datasets methods base

other attached packages: [1] raster_2.1-16 sp_1.0-8

loaded via a namespace (and not attached): [1] grid_3.0.0 lattice_0.20-15

Any help is appreciated

Solution

  • You can try to use setMinMax() on your raster file to try and work out the min and max values and store them in the returned Raster* object. Try it like so:

    r <- setMinMax( raster("path/to/myraster.asc") )

    I am not sure what is happening because if I downlaod you data and do:

    r1 <- raster( "~/Downloads/test.asc")
summary(values(r1))
     Min.   1st Qu.    Median      Mean   3rd Qu.      Max.      NA's 
-69830000  -4789000    737300  16950000  13880000 167800000     71468

    Please add the output of sessionInfo() into your question , i.e. not as a comment.

    The errors in this case were being caused by not having rgdal installed, which are bindings to the Geospatial Data Abstraction Library and are very important for importing/exporting raster and shapefile data.