pgirmess (version 1.3.9)

write.arcGrid: Writes an ArcInfo ASCII grid from a matrix or data frame, with x, y, z values.

Description

Writes an ArcInfo ASCII grid from a matrix or data frame, with x, y, z values

Usage

write.arcGrid(xyz, file, zcol = 3, xcol = 1, ycol = 2, NODATA = -9999)

Arguments

xyz

a matrix or a data frame with x, y, z values

file

a character string naming the file to write to

zcol

the column number for the z-axis

xcol

the column number for the x-axis

ycol

the column number for the y-axis

NODATA

the value for no data

Value

• An ArcInfo ASCII grid file

Details

A "gap stopper" function that can be used eg to export 2D kernel densities or any object for which a raster representation make sense. Such file can be imported on-the-fly from FWTools (Open Source GIS Binary Kit for Windows and Linux) , if no data is a number. This plateform can export to Gtiff format readable with ArcGIS. The ESRI ArcToolBox does not read the "ArcInfo ASCII grid file" for some reasons.

Examples

library(splancs)
data(bodmin)   
mykernel<-kernel2d(as.points(bodmin), bodmin$poly, h0=2, nx=100, ny=100)
attributes(mykernel$z)<-NULL
mykernel$z[is.na(mykernel$z)]<--9999
mydata<-cbind(expand.grid(mykernel$x,mykernel$y),mykernel$z)
write.arcGrid(mydata,file="mytextgrid",NODATA=-9999)