i.ortho.rectify(1grass)
NAME
i.ortho.rectify - Orthorectifies an image by using the image to photo coordinate transformation matrix.
KEYWORDS
imagery, orthorectify
SYNOPSIS
i.ortho.rectify
i.ortho.rectify --help
i.ortho.rectify [-ca] group=name [input=name[,name,...]]
extension=string [resolution=float] [memory=memory in MB]
[method=string] [angle=name] [--overwrite] [--help] [--verbose]
[--quiet] [--ui]
Flags:
-c
Use current region settings in target location (def.=calculate
smallest area)
-a
Rectify all raster maps in group
--overwrite
Allow output files to overwrite existing files
--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
input=name[,name,...]
Name of input raster map(s)
extension=string [required]
Output raster map(s) suffix
resolution=float
Target resolution (ignored if -c flag used)
memory=memory in MB
Amount of memory to use in MB
Default: 300
method=string
Interpolation method to use
Options: nearest, linear, cubic, lanczos, linear_f, cubic_f,
lanczos_f
Default: nearest
angle=name
Raster map with camera angle relative to ground surface
DESCRIPTION
i.photo.rectify rectifies an image by using the image to photo
coordinate transformation matrix created by i.photo.2image and the
rectification parameters created by i.photo.2target. Rectification is
the process by which the geometry of an image is made planimetric.
This is accomplished by mapping an image from one coordinate system to
another. In i.photo.rectify the parameters computed by i.photo.2image
and i.photo.2target are used in equations to convert x,y image
coordinates to standard map coordinates for each pixel in the image.
The result is an image with a standard map coordinate system,
compensated for relief distortions and photographic tilt. Upon
completion of the program the rectified image is deposited in a
previously targeted GRASS LOCATION.
Images can be resampled with various different interpolation methods:
nearest neighbor assignment, bilinear and bicubic interpolation. The
bilinear and bicubic interpolation methods are also available with a
fallback option. These methods "fall back" to simpler interpolation
methods along NULL borders. That is, from bicubic to bilinear to
nearest.
The process may take an hour or more depending on the size of the
image, the speed of the computer, the number files, and the size and
resolution of the selected window.
The rectified image will be located in the target LOCATION when the
program is completed. The original unrectified files are not modified
or removed.
The optional angle output holds the camera angle in degrees to the
local surface, considering local slope and aspect. A value of 90
degrees indicates that the camera angle was orthogonal to the local
surface, a value of 0 degrees indicates that the camera angle was
parallel to the local surface and negative values indicate that the
surface was invisible to the camera. As a rule of thumb, values below
30 degrees indicate problem areas where the orthorectified output will
appear blurred. Because terrain shadowing effects are not considered,
areas with high camera angles may also appear blurred if they are
located (viewed from the camera position) behind mountain ridges or
peaks.
i.photo.rectify can be run directly, specifying options in the command
line or the GUI, or it can be invoked as OPTION 8 through
i.ortho.photo. If invoked though i.ortho.photo, an interactive terminal
is used to determine the options.
Interactive mode
You are first asked if all images within the imagery group should be
rectified. If this option is not chosen, you are asked to specify for
each image within the imagery group whether it should be rectified or
not.
More than one file may be rectified at a time. Each file should have a
unique output file name. The next prompt asks you for an extension to
be appended to the rectified images.
The next prompt will ask you whether a camera angle map should be
produced and if yes, what should be its name.
After that you are asked if overwriting existing maps in the target
location and mapset should be allowed.
The next prompt asks you to select one of two windows:
Please select one of the following options
1. Use the current window in the target location
2. Determine the smallest window which covers the image
>
If you choose option 2, you can also specify a desired target
resolution.
i.photo.rectify will only rectify that portion of the image that occurs
within the chosen window. Only that portion will be relocated in the
target database. It is therefore important to check the current window
in the target LOCATION if choice number one is selected.
Next you are asked to select an interpolation method.
Please select one of the following interpolation methods
1. nearest neighbor
2. bilinear
3. bicubic
4. bilinear with fallback
5. bicubic with fallback
>
The last prompt will ask you about the amount of memory to be used by
i.photo.rectify.
SEE ALSO
i.ortho.photo
i.ortho.camera
i.photo.2image
i.photo.2target
i.ortho.init
i.rectify
AUTHOR
Mike Baba, DBA Systems, Inc. Updated rectification and elevation map to FP 1/2002 Markus Neteler Bugfixes and enhancements 12/2010 Markus Metz Last changed: $Date: 2013-02-20 02:16:02 -0800 (Wed, 20 Feb 2013) $
SOURCE CODE
Available at: i.ortho.rectify source code (history)
Main index | Imagery index | Topics index | Keywords index | Graphical
index | Full index
2003-2016 GRASS Development Team, GRASS GIS 7.2.0 Reference Manual
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
