r.out.ntv2 - GRASS GIS manual

Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.

NAME

r.out.ntv2 - Exports NTv2 datum transformation grid

KEYWORDS

SYNOPSIS

r.out.ntv2

r.out.ntv2 --help

r.out.ntv2 latshift=string lonshift=string output=string [systemt=string] [majort=string] [minort=string] [systemf=string] [majorf=string] [minorf=string] [--help] [--verbose] [--quiet] [--ui]

Flags:

--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

latshift=string [required]: Input raster map of lattitude datum shift values
lonshift=string [required]: Input raster map of longitude datum shift values
output=string [required]: Output NTv2 datum transformation grid file
systemt=string: Transformation grid's destination coordinate system name; Default: WGS84
majort=string: Major ellipsoid axis of the transformation grid's destination coordinate system; Default: 6378137
minort=string: Minor ellipsoid axis of the transformation grid's destination coordinate system; Default: 6356752.314245
systemf=string: Transformation grid's input coordinate system name; Default: UNKNOWN
majorf=string: Major ellipsoid axis of the transformation grid's input coordinate system; Default: UNKNOWN
minorf=string: Minor ellipsoid axis of the transformation grid's input coordinate system; Default: UNKNOWN

DESCRIPTION
NOTES
SEE ALSO
AUTHOR

DESCRIPTION

r.out.ntv2 converts a pair of GRASS raster maps containing longitude and lattitude coordinate offsets into an NTv2 grid datum shift file.

NOTES

NTv2 format supports only single-precission floating point data. GRASS GIS double-precision DCELL data need to be reduced to FCELL before export, eg. using r.mapcalc float() function.

The user should adjust the region and resolution to match the input raster maps before export, using g.region.

PROJ.4 and the software that depend on it, including GDAL, GRASS, QGIS, assume the NTv2 grid's destination coordinate system to be WGS84. The metadata values in the grid's header set with majort, minort, systemt parameters are ignored, same as the input coordinate system parameters (majorf, minorf, systemf). They are for documentation purposes only.

The CREATED and UPDATED output grid's metadata fields are set to, respectively, current date and time, in YYYYMMDD and HHMMSS format.

AUTHOR

Maciej Sieczka

SOURCE CODE

Available at: r.out.ntv2 source code (history)

Latest change: Thursday Feb 03 09:32:35 2022 in commit: f17c792f5de56c64ecfbe63ec315307872cf9d5c