Ubuntu Manpage: i.ortho.photo - Menu driver for the photo imagery programs.

NAME

       i.ortho.photo  - Menu driver for the photo imagery programs.

KEYWORDS

       imagery, orthorectify

SYNOPSIS

       i.ortho.photo
       i.ortho.photo help
       i.ortho.photo group=name  [--verbose]  [--quiet]

   Parameters:
       group=name
           Name of imagery group for ortho-rectification

DESCRIPTION

i.ortho.photo allows the user to ortho-rectify imagery group files. An imagery group
consists of several scanned aerial photographs (raster maps) of a common area. Imagery
groups can be created or modified using the GRASS Image Processing Program i.group, or
using the first menu option described below. i.ortho.photo guides the user through the
steps required to ortho-rectify the raster maps in a single imagery group.

The first menu in i.ortho.photo provides the user with the following options:

Initialization Options:
1) Select/Modify imagery group
2) Select/Modify imagery group target
3) Select/Modify target elevation model
4) Select/Modify imagery group camera

Transformation Parameter Computation:
5) Compute image-to-photo transformation parameters
6) Initialize exposure station parameters
7) Compute photo-to-target transformation parameters

Ortho-rectification Option:
8) Ortho-rectify imagery group raster maps

RETURN to exit
>

To ortho-rectify aerial images the user has to follow the menu options step by step.
Generally the user builds a target location containing a projected DEM and a map reference
(topo sheet or other map). Another xy-location will contain the aerial photo. The entire
rectification process is started within the xy-location. First the target to the projected
location has to be set (i.target), then the image references (fiducial points) will be
defined. After describing the camera parameters, reference points from aerial image to the
topo sheet from the target location will be set. The local elevation will be taken from
the target DEM. Finally the aerial image will be rectified.

The options to follow are described as follows:

1. Select/Modify imagery group
The current imagery group is display at the top of the previous menu. You may
select another (new or existing) imagery group for the ortho-rectification program
using option (1). After choosing option (1) you will be prompted for the name of a
new or existing imagery group. Option (1) using the GRASS Image Processing Program
i.group, for creation or modification of imagery groups. For more information on
imagery group creation or modification please the the GRASS manual page for
i.group.

2. Select/Modify imagery group target
The target location and mapset may be selected or modified using option (2). After
choosing option (2) you will be prompted for the names of the target location and
mapset, where the ortho-rectified raster maps will reside. The target location is
also the location from which the elevation model (raster map) will be selected --
see option (3). Option (2) uses the GRASS Image Processing Program i.target, for
selection or modification of the imagery group target location and mapset. For
more information on imagery group selection or modification please the the GRASS
manual page for i.target.

3. Select/Modify target elevation model
Option (3) allows you to select the raster map from the target location to be used
as the elevation model. The elevation model is required for both the computation
of photo-to-target parameters (option 6) and for the ortho-rectification of the
imagery group files (option 8). The raster map select for the elevation model
should cover the entire area of the image group to be ortho-rectified. Currently,
the elevation model raster map is expected to be in units of meters. DTED and DEM
files are suitable for use as the elevation model in the ortho-rectification
program. After selection option (3) you will be prompted for the name of the
raster map in the target location that you want to use as the elevation model.

4. Select/Modify imagery group camera
Using option (4) you may select or create an camera reference file that will be
used with the current imagery group. A camera reference file contains information
on the internal characteristics of the aerial camera, as well as the geometry of
the fiducial or reseau marks. The most important characteristic of the camera is
its focal length. Fiducial or reseau marks locations are required to compute the
scanned image to photo-coordinate transformation parameter (option 5). For a more
detailed description of option (4) please see the GRASS manual page for
i.photo.camera.

5. Compute image-to-photo transformation parameters
The scanned image to photo-coordinate transformation parameters are computed using
option (5). In this interactive option you associate scanned reference points
(fiducials, reseau marks, etc.) with their known photo coordinates from the camera
reference file. Complete documentation for this option is available under the
manual entry i.photo.2image.

6. Initialize exposure station parameters
If option (6) is selected, initial camera exposure station parameters and initial
variances may be selected or modified. Complete documentation for this option is
available under the manual entry i.photo.init.

7. Compute photo-to-target transformation parameters
The photo to target transformation parameters are compute using option (7). Here
control points are marked on one or more imagery group files and associated with
there known standard (e.g. UTM) and elevation coordinates. Complete documentation
for this option is available under the manual entry i.photo.2target.

8. Ortho-photo imagery group files
Option (8) is used to perform the actual image ortho-rectification after all of the
transformation parameters have been computed. Ortho-rectified raster files will be
created in the target location for each selected imagery group file. You may
select either the current window in the target location or the minimal bounding
window for the ortho-rectified image. Complete documentation for this option is
available under the manual entry i.photo.rectify.

NOTES

       i.ortho.photo currently requires the elevation model to  be  in  meters,  and  the  target
       location to be a standard (e.g. UTM) coordinate system.

REFERENCES

                      Wolf,   P.R.   (1983):   Elements   of   Photogrammetry,   With  Air  Photo
                     Interpretation and Remote Sensing. 2nd ed. McGraw Hill, 562 pages

                      Rocchini, D.,  Metz,  M.,  Frigeri,  A.,  Delucchi,  L.,  Marcantonio,  M.,
                     Neteler,  M.  (2012).  Robust rectification of aerial photographs in an open
                     source environment. Computers & Geosciences 39 (2): 145-151.

AUTHOR

       Mike Baba,  DBA Systems, Inc.

       Updated rectification and elevation map to FP 1/2002 Markus Neteler

       Last changed: $Date: 2012-01-08 13:48:21 -0800 (Sun, 08 Jan 2012) $

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       © 2003-2013 GRASS Development Team