NAME

       i.ortho.transform  - Computes a coordinate transformation based on the control points.

KEYWORDS

       imagery, orthorectify, transformation, GCP

SYNOPSIS

       i.ortho.transform
       i.ortho.transform --help
       i.ortho.transform    [-srx]   group=name    [format=string[,string,...]]     [coords=name]
       [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -s
           Display summary information

       -r
           Reverse transform of coords file or coeff. dump
           Target east,north,height coordinates to local x,y,z

       -x
           Display transform matrix coefficients

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       group=name [required]
           Name of input imagery group

       format=string[,string,...]
           Output format
           Options: idx, src, dst, fwd, rev, fxy, rxy, fd, rd
           Default: fd,rd
           idx: point index
           src: source coordinates
           dst: destination coordinates
           fwd: forward coordinates (destination)
           rev: reverse coordinates (source)
           fxy: forward coordinates difference (destination)
           rxy: reverse coordinates difference (source)
           fd: forward error (destination)
           rd: reverse error (source)

       coords=name
           File containing coordinates to transform ("-" to read from stdin)
           Local x,y,z coordinates to target east,north,height

DESCRIPTION

       i.ortho.transform is an utility to compute transformation based upon GCPs and output error
       measurements.

NOTES

       For  coordinates  given with the coords file option or fed from stdin, the input format is
       "x y z" with one coordinate pair per line.

       The transformations are:

       order=1:
           e = [E0 E1][1].[1]
               [E2  0][e] [n]
           n = [N0 N1][1].[1]
               [N2  0][e] [n]
       order=2:
           e = [E0 E1 E3][1 ] [1 ]
               [E2 E4  0][e ].[n ]
               [E5  0  0][e²] [n²]
           n = [N0 N1 N3][1 ] [1 ]
               [N2 N4  0][e ].[n ]
               [N5  0  0][e²] [n²]
       order=3:
           e = [E0 E1 E3 E6][1 ] [1 ]
               [E2 E4 E7  0][e ].[n ]
               [E5 E8  0  0][e²] [n²]
               [E9  0  0  0][e³] [n³]
           n = [N0 N1 N3 N6][1 ] [1 ]
               [N2 N4 N7  0][e ].[n ]
               [N5 N8  0  0][e²] [n²]
               [N9  0  0  0][e³] [n³]
       ["." = dot-product, (AE).N = N’EA.]

       In other words, order=1 and order=2 are equivalent to order=3 with the higher coefficients
       equal to zero.

SEE ALSO

       i.rectify

TODO

       Update this document with x,y,z<->E,N,H information

AUTHORS

       Brian J. Buckley
       Glynn Clements
       Hamish Bowman

       Last changed: $Date: 2017-04-07 18:41:10 +0200 (Fri, 07 Apr 2017) $

SOURCE CODE

       Available at: i.ortho.transform source code (history)

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       © 2003-2018 GRASS Development Team, GRASS GIS 7.4.0 Reference Manual