r.in.ascii(1)

NAME
r.in.ascii - Convert an ASCII raster text file into a (binary) raster map layer.

KEYWORDS
raster

SYNOPSIS
r.in.ascii
r.in.ascii help
r.in.ascii [-ifds] input=name output=name [title="phrase"] [mult=float] [nv=string] [--overwrite]

  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

--overwrite

  Parameters:

input=name
    Ascii raster file to be imported

output=name
    Name for output raster map

title=
    Title for resultant raster map

mult=float
    Multiplier for ascii data Default: 1.0 or read from header

nv=string
    String representing NULL value data cell Default: * or read from header

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

The GRASS ASCII 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 NW value occurs at the beginning of the first line of data, and the SW value occurs at the beginning of the last line of data.

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.

SEE ALSO
r.out.ascii, r.in.arc, r.in.gdal, r.out.arc, r.in.bin, r3.in.ascii, GRASS ASCII formats

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

Last changed: $Date: 2006/10/16 12:38:30 $

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