The ASC Arc/Info ASCII filter imports and exports ASC Arc/Info ASCII grid files.
File Description
An Esri grid is a raster GIS file format developed by Esri. The ASCII format is also known as Arc/Info ASCII grid. The ASCII format is used as an elevation grid exchange, or export format, with a simple ASCII file structure.
File Format
The first six lines of the file indicate the reference of the grid, followed by the values listed in the order they would appear (left to right and top to bottom).
Example
ncols 4
nrows 6
xllcorner 0.0
yllcorner 0.0
cellsize 50.0
NODATA_value -9999
-9999 -9999 5 2
-9999 20 100 36
3 8 35 10
32 42 50 6
88 75 27 9
13 5 1 -9999
Where:
· ncols
are the numbers of rows (represented as integers);
· and nrows
are the numbers of rows (represented as integers);
· xllcorner
and yllcorner
are the western (left) X coordinate and southern (bottom) Y coordinates, such as easting and northing (represented as real numbers with an optional decimal point)
· cellsize
is the length of one side of a square cell (a real number)
· nodata_value
is the value that is regarded as "missing" or "not applicable"; this line is optional, but highly recommended as some programs expect this line to be declared (a real number).
The remainder of the file lists the raster values for each cell, starting at the upper-left corner. These real numbers (with optional decimal point, if needed) and are delimited using a single space character.
File Name Extensions
.ASC, .AIG, .AGR, .GRD
Import Method
Choose the File | Import command.
Export Method
Select a lattice or image module and choose the File | Save Data command.
ESRII ASCII Grid Format Warning Dialog
When exporting, the ESRII ASCII Grid Format Warning dialog may appear.
The ESRII ASCII Grid Format Warning dialog
Click the Yes button to continue export. Click the No button to abort the export.
See Also