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asciigrid R

3 messages · Jose Funes, Michael Sumner, Roger Bivand

Original
Jose Funes
# 
ASCIIGRID

I am using read.asciigrid function from R to import 4 grid maps from
ArcGIS to a single grid in R. However, I am having troubles to make it
work, when I finish to import the 4 grid to R the final grid appear as
NULL. Below I did include the code, I will appreciate your help to
solve this problem.I tried to register to GTAT group but my email is
returned.

Thanks,

R code:

Four layers were stacked:
explanatory$silt = read.asciigrid("silt.asc")$band1
explanatory$silt = explanatory$band1

explanatory$sand = read.asciigrid("sandasc.asc")$band1
explanatory$sand = explanatory$band1

explanatory$nd = read.asciigrid("nd.asc")$band1
explanatory$nd = explanatory$band1

explanatory$bnd3 = read.asciigrid("bnd3.asc")$band1
explanatory$bnd3 = explanatory$band1


Deleting double band:
explanatory$band1 = NULL

 str(explanatory)
 NULL

Jose Funes
Michael Sumner
# 
Try this, you were nulling each column as you read it, and you didn't 
let us know how "expanatory" was created in the first place:

explanatory = read.asciigrid("silt.asc")
names(explanatory) <- "silt"

explanatory$sand = read.asciigrid("sandasc.asc")$band1

explanatory$nd = read.asciigrid("nd.asc")$band1

explanatory$bnd3 = read.asciigrid("bnd3.asc")$band1
Jose Funes wrote:
Roger Bivand
#
On Mon, 3 Dec 2007, Jose Funes wrote:

            

      
      
      
    

        
Maybe:

library(maptools)
explanatory <- readAsciiGrid("silt.asc")
explanatory <- cbind(explanatory, readAsciiGrid("sandasc.asc"))
explanatory <- cbind(explanatory, readAsciiGrid("nd.asc"))
explanatory <- cbind(explanatory, readAsciiGrid("bnd3.asc"))
names(explanatory) <- c("silt", "sand", "nd", "bnd3")

Please also see ?readAsciiGrid and check the dec= and the na.value= 
arguments - the version you are using in sp is not as often used as the 
one in maptools. You can also use readGDAL() in the rgdal package.

Roger