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Raster to ASCII (Conversion Tools)

Summary

Converts a raster dataset to an ASCII file representing raster data.

Usage

  • The input raster dataset can be any valid raster dataset.

  • The structure of the ASCII file consists of header information containing a set of keywords, followed by cell values in row-major order.

    The format of the file in general is:

    NCOLS xxx
NROWS xxx
XLLCORNER xxx
YLLCORNER xxx
CELLSIZE xxx
NODATA_VALUE xxx
row 1
row 2
.
.
row n

    The definitions of the keywords are as follows:

    • NCOLS and NROWS are the number of columns and rows in the raster defined by the ASCII file.

    • XLLCORNER and YLLCORNER are the coordinates of the lower left corner of the lower left cell.

    • CELLSIZE is the cell size of the raster.

    • NODATA_VALUE is the value that is to represent NoData cells.

    • In the data stream of cell values, row 1 of the data is the top of the raster, row 2 is just under row 1, and so on.

  • An example of an ASCII raster file is:

    NCOLS 480
NROWS 450
XLLCORNER 378922
YLLCORNER 4072345
CELLSIZE 30
NODATA_VALUE -32768
43 2 45 7 3 56 2 5 23 65 34 6 32 54 57 34
35 45 65 34 2 6 78 4 2 6 89 3 2 7 45 23 5 ...

    NODATA_VALUE in the example above is the value in the ASCII file that will represent cells that are NoData in the input raster. This value is normally reserved for those cells whose true value is unknown.

  • The end of each row of data from the raster is terminated with a carriage return character in the file.

  • Both integer and floating-point rasters can be converted to an ASCII raster file.

  • This tool only writes the origin as the lower left corner of the lower left cell. The Copy Raster tool also supports the origin as the center of the lower left cell.

  • At ArcGIS Pro 3.2 and later, the default tool output is an ASCII file with an .asc extension, not a .txt extension. For existing ASCII files with a .txt extension, renaming the file using the .asc extension is recommended.

Parameters

Label Explanation Data type

Input raster

The input raster dataset.

The raster can be integer or floating-point type.

Raster Layer

Output ASCII raster file

The output ASCII raster file.

File

Environments

Auto Commit, Cell Size, Cell Size Projection Method, Current Workspace, Extent, Geographic Transformations, Output CONFIG Keyword, Output Coordinate System, Scratch Workspace

Licensing information

  • Basic: Yes
  • Standard: Yes
  • Advanced: Yes