GRASS GIS manual: r3.in.ascii

NAME

r3.in.ascii - Converts a 3D ASCII raster text file into a (binary) 3D raster map.

KEYWORDS

raster3d, voxel, import

SYNOPSIS

r3.in.ascii
r3.in.ascii help
r3.in.ascii input=name output=name [nv=string] [type=string] [precision=string] [compression=string] [tiledimension=XxYxZ] [--overwrite] [--verbose] [--quiet]

Flags:

--overwrite: Allow output files to overwrite existing files
--verbose: Verbose module output
--quiet: Quiet module output

Parameters:

input=name [required]: ASCII raster map to be imported
output=name [required]: Name for output 3D raster map
nv=string: String representing NULL value data cell (use 'none' if no such value); Default: *
type=string: Data type used in the output raster3d map; Options: default, double, float; Default: default
precision=string: Number of digits used as mantissa in the internal map storage, 0 -23 for float, 0 - 52 for double, max or default; Default: default
compression=string: The compression method used in the output raster3d map; Options: default, rle, none; Default: default
tiledimension=XxYxZ: The dimensions of the tiles used in the output raster3d map (XxYxZ or default: 16x16x8); Default: default

DESCRIPTION

r3.in.ascii allows a user to create a (binary) GRASS 3D raster map layer from a 3D ASCII raster input file with (optional) TITLE.

Note that for compression the none option only specifies that neither LZW nor RLE is used for compression. It does not turn off the compression all together. 3D raster maps do not support non-compressed files.

The tiledimension parameter defines the dimension of the tiles used in the output file. The format is: XxYxZ

The nv parameter specifies which value to convert to NULL-value. If the specified value is none, no conversion is performed. Default is none.

The volume coordinate system and tile layout of the inported voxel map

NOTES

The format of the 3D ASCII file:

version: "grass7"
order:   "nsbt" or "nstb" or "snbt" or "sntb"
north:   floating point
south:   floating point
east:    floating point
west:    floating point
top:     floating point
bottom:  floating point
rows:    integer
cols:    integer
levels:  integer

The version and order option have been introduced in GRASS 7 in June 2011. The version option is self explaining. The order option specifies the row and depth order of the data in the input file. The supported row/depth ordering is documented in the r3.out.ascii manual page. The order of the data in the input file does not specifiy the data order in the generated output 3D raster map which is in any case north -> south, west -> east, bottom -> top order. So dependent on the order information the data is automatically imported into the correct internal coordinate system.

The version and order options are not mandatory. In case no version and order option is specified, the default GRASS 6 ASCII format is assumed.

This header is followed by the cell values in floating point format organized in rows with constant col and level coordinate. The rows are organized by constant level coordinate. Individual cell values are separated by space or CR.

EXAMPLES

4x3x2 sample. Note in case no specific ordering is specified in the input file the upper-left (NW) corner of the bottom level comes first. The according order option is: nsbt for north -> south, bottom -> top ordering. This is identical with r.in.ascii for single level data. So the y coordinate is 0 at the northern edge.

north: 3.0
south: 0.0
east: 4.0
west: 0.0
top: 2.0
bottom: 0.0
rows: 3
cols: 4
levels: 2
x1,y1,z1  x2,y1,z1  x3,y1,z1  x4,y1,z1
x1,y2,z1  x2,y2,z1  x3,y2,z1  x4,y2,z1
x1,y3,z1  x2,y3,z1  x3,y3,z1  x4,y3,z1
x1,y1,z2  x2,y1,z2  x3,y1,z2  x4,y1,z2
x1,y2,z2  x2,y2,z2  x3,y2,z2  x4,y2,z2
x1,y3,z2  x2,y3,z2  x3,y3,z2  x4,y3,z2

Note that unit tests for r3.in.ascii are implemented in the test.r3.out.ascii.sh script located in the r3.out.ascii directory.

AUTHORS

Roman Waupotitsch, Michael Shapiro, Helena Mitasova, Bill Brown, Lubos Mitas, Jaro Hofierka, Sören Gebbert