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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

Table of contents

DESCRIPTION

r.out.ntv2 converts a pair of GRASS raster maps containing longitude and lattitude coordinate offsets into an NTv2 grid datum shift file (if this document dissapeared it might have been moved to the new PROJ.4 wiki).

NOTES

NTv2 format supports only single-precission floating point data. GRASS 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.

SEE ALSO

NTv2 format description by ESRI

AUTHOR

Maciej Sieczka

Last changed: $Date: 2016-05-25 11:29:11 +0200 (Wed, 25 May 2016) $

SOURCE CODE

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


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