r.in.ascii

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 [-ifds] 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

Flags:

-i: integer values are imported
-f: floating point values are imported
-d: double floating point values are imported
-s: SURFER (Golden Software) ascii grid file will be imported

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.

Optionally the following parameters can be defined in the header section:

null: nn type: float multiplier: 2.

"null" defines a string or number to be converted to NULL value (no data).
"type" defines the data type (int, float double) and is not required.
"multiplier" is an optional parameter to multiply each cell value.

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 null: -9999 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.

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.

AUTHOR

Michael Shapiro, U.S. Army Construction Engineering Research Laboratory
Surfer support by Roger Miller

Last changed: $Date: 2003/05/27 05:11:21 $