epi.asc: Write matrix to an ASCII raster file

In epiR: Tools for the Analysis of Epidemiological Data

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.
file	character string specifying the name and path of the ASCII raster output file.
xllcorner	the easting coordinate corresponding to the lower left hand corner of the matrix.
yllcorner	the northing coordinate corresponding to the lower left hand corner of the matrix.
cellsize	number, defining the size of each matrix cell.
na	scalar, defines null values in the matrix. NAs are converted to this value.

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:

1	3
2	4

is displayed (using image) as:

3	4
1	2

It is recommended that the source data for this function is a matrix. Replacement of NAs in a data frame extends processing time for this function.

epiR documentation built on Sept. 30, 2024, 9:16 a.m.