NAME

r.in.ascii - Convert an ASCII raster text file into a (binary) raster map layer.
(GRASS Raster Data Import Program)

SYNOPSIS

r.in.ascii
r.in.ascii help
r.in.ascii input=name output=name [title="phrase"] [mult=multiplier]

DESCRIPTION

r.in.ascii allows a user to create a (binary) GRASS raster map layer from an ASCII raster input file with (optional) title.

OPTIONS

Parameters:

input=name
Name of an existing ASCII raster file to be imported.
output=name
Name to be assigned to resultant binary raster map layer.
title="phrase"
Title to be assigned to resultant raster map layer.
mult=multiplier
Multiply all raster cell values by multiplier. multiplier is a floating point value, and has a default value of 1.0.
The input file has a header section which describes the location and size of the data, followed by the data itself.

The header has 6 lines: 

north:   xxxxxx.xx
south:   xxxxxx.xx 
east:    xxxxxx.xx 
west:    xxxxxx.xx 
rows:    r 
cols:    c

The north, south, east, and west field values entered are the coordinates of the edges of the geographic region. The rows and cols field values entered describe the dimensions of the matrix of data to follow. The data which follows is r rows of c integers.

EXAMPLE

The following is a sample input file to r.in.ascii: 
north:                   4299000.00
south:                   4247000.00
east:                     528000.00
west:                     500000.00
rows:                         10   
cols:                         15   

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

NOTES

The geographic coordinates north, south, east, and west describe the outer edges of the geographic region. They run along the edges of the cells at the edge of the geographic region and not through the center of the cells at the edges.

The data (which follows the header section) must contain r x c values, but it is not necessary that all the data for a row be on one line. A row may be split over many lines.

r.in.ascii handles floating point cell values, but truncates them into integer values. The mult option allows the number of significant figures of a floating point cell to be increased before truncation to an integer. Multiples of ten are the most functional multipliers.

The header information in ESRI Raster ASCII files differs from GRASS. To convert an Arc/Info (ArcView) ASCII grid file into GRASS, click here. Also, see r.in.arc to import ESRI Raster ASCII files.

SEE ALSO

r.out.ascii, r.in.arc, r.out.arc

AUTHOR

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory