Last data update: 2014.03.03
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R: Write matrix to an ASCII raster file
Write matrix to an ASCII raster file
Description
Writes a data frame to an ASCII raster file, suitable for display in a Geographic Information System.
Usage
epi.asc(dat, file, xllcorner, yllcorner, cellsize, na = -9999)
Arguments
dat |
a matrix with data suitable for plotting using the image function.
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file |
character string specifying the name and path of the ASCII raster output file.
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xllcorner |
the easting coordinate corresponding to the lower left hand corner of the matrix.
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yllcorner |
the northing coordinate corresponding to the lower left hand corner of the matrix.
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cellsize |
number, defining the size of each matrix cell.
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na |
scalar, defines null values in the matrix. NAs are converted to this value.
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Value
Writes an ASCII raster file (typically with *.asc extension), suitable for display in a Geographic Information System.
Note
The image function in R rotates tabular data counter clockwise by 90 degrees for display. A matrix of the form:
is displayed (using image ) as:
It is recommended that the source data for this function is a matrix. Replacement of NA s in a data frame extends processing time for this function.
Results
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