1i.ortho.rectify(1)          GRASS GIS User's Manual         i.ortho.rectify(1)
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NAME

6       i.ortho.rectify   - Orthorectifies an image by using the image to photo
7       coordinate transformation matrix.
8

KEYWORDS

10       imagery, orthorectify
11

SYNOPSIS

13       i.ortho.rectify
14       i.ortho.rectify --help
15       i.ortho.rectify  [-cap]  group=name   [input=name[,name,...]]    exten‐
16       sion=string      [resolution=float]       [memory=memory     in     MB]
17       [method=string]   [angle=name]   [--overwrite]   [--help]   [--verbose]
18       [--quiet]  [--ui]
19
20   Flags:
21       -c
22           Use  current  region  settings  in  target location (def.=calculate
23           smallest area)
24
25       -a
26           Rectify all raster maps in group
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28       -p
29           Enable panorama camera correction
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31       --overwrite
32           Allow output files to overwrite existing files
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34       --help
35           Print usage summary
36
37       --verbose
38           Verbose module output
39
40       --quiet
41           Quiet module output
42
43       --ui
44           Force launching GUI dialog
45
46   Parameters:
47       group=name [required]
48           Name of input imagery group
49
50       input=name[,name,...]
51           Name of input raster map(s)
52
53       extension=string [required]
54           Output raster map(s) suffix
55
56       resolution=float
57           Target resolution (ignored if -c flag used)
58
59       memory=memory in MB
60           Maximum memory to be used (in MB)
61           Cache size for raster rows
62           Default: 300
63
64       method=string
65           Interpolation method to use
66           Options: nearest, linear, cubic, lanczos, linear_f, cubic_f,  lanc‐
67           zos_f
68           Default: nearest
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70       angle=name
71           Raster map with camera angle relative to ground surface
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DESCRIPTION

74       i.photo.rectify  rectifies an image by using the image to photo coordi‐
75       nate transformation matrix created by i.photo.2image and the rectifica‐
76       tion  parameters  created  by  i.photo.2target.   Rectification  is the
77       process by which the geometry of an image is made planimetric.  This is
78       accomplished by mapping an image from one coordinate system to another.
79       In  i.photo.rectify  the  parameters  computed  by  i.photo.2image  and
80       i.photo.2target  are used in equations to convert x,y image coordinates
81       to standard map coordinates for each pixel in the image.  The result is
82       an  image with a standard map coordinate system, compensated for relief
83       distortions and photographic tilt. Upon completion of the  program  the
84       rectified image is deposited in a previously targeted GRASS LOCATION.
85
86       Images  can  be resampled with various different interpolation methods:
87       nearest neighbor assignment, bilinear and  bicubic  interpolation.  The
88       bilinear  and  bicubic  interpolation methods are also available with a
89       fallback option. These methods "fall  back"  to  simpler  interpolation
90       methods  along NULL borders. That is, from bicubic to bilinear to near‐
91       est.
92
93       The process may take an hour or more depending on the size of  the  im‐
94       age, the speed of the computer, the number files, and the size and res‐
95       olution of the selected window.
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97       The rectified image will be located in the  target  LOCATION  when  the
98       program  is  completed. The original unrectified files are not modified
99       or removed.
100
101       The optional angle output holds the camera angle in degrees to the  lo‐
102       cal  surface, considering local slope and aspect. A value of 90 degrees
103       indicates that the camera angle was orthogonal to the local surface,  a
104       value  of 0 degrees indicates that the camera angle was parallel to the
105       local surface and negative values indicate that the surface was invisi‐
106       ble to the camera. As a rule of thumb, values below 30 degrees indicate
107       problem areas where the orthorectified output will appear blurred.  Be‐
108       cause  terrain  shadowing  effects  are not considered, areas with high
109       camera angles may also appear blurred if they are located (viewed  from
110       the camera position) behind mountain ridges or peaks.
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112       i.photo.rectify  can be run directly, specifying options in the command
113       line or the GUI, or it  can  be  invoked  as  OPTION  8  through  i.or‐
114       tho.photo.  If invoked though i.ortho.photo, an interactive terminal is
115       used to determine the options.
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117   Interactive mode
118       You are first asked if all images within the imagery  group  should  be
119       rectified.  If  this option is not chosen, you are asked to specify for
120       each image within the imagery group whether it should be  rectified  or
121       not.
122
123       More  than one file may be rectified at a time. Each file should have a
124       unique output file name. The next prompt asks you for an  extension  to
125       be appended to the rectified images.
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127       The  next prompt will ask you whether a camera angle map should be pro‐
128       duced and if yes, what should be its name.
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130       After that you are asked if overwriting existing maps in the target lo‐
131       cation and mapset should be allowed.
132
133       The next prompt asks you to select one of two windows:
134
135             Please select one of the following options
136             1.   Use the current window in the target location
137             2.   Determine the smallest window which covers the image
138             >
139
140       If  you  choose option 2, you can also specify a desired target resolu‐
141       tion.
142
143       i.photo.rectify will only rectify that portion of the image that occurs
144       within  the  chosen window.  Only that portion will be relocated in the
145       target database. It is therefore important to check the current  window
146       in the target LOCATION if choice number one is selected.
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148       Next you are asked to select an interpolation method.
149             Please select one of the following interpolation methods
150             1. nearest neighbor
151             2. bilinear
152             3. bicubic
153             4. bilinear with fallback
154             5. bicubic with fallback
155             >
156
157       The  last  prompt will ask you about the amount of memory to be used by
158       i.photo.rectify.
159

SEE ALSO

161        i.ortho.photo
162       i.ortho.camera
163       i.photo.2image
164       i.photo.2target
165       i.ortho.init
166       i.rectify
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AUTHORS

169       Mike Baba, DBA Systems, Inc.
170       Updated rectification and elevation map to FP 1/2002 Markus Neteler
171       Bugfixes and enhancements 12/2010 Markus Metz
172

SOURCE CODE

174       Available at: i.ortho.rectify source code (history)
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176       Accessed: Saturday Jan 21 20:40:53 2023
177
178       Main index | Imagery index | Topics index | Keywords index |  Graphical
179       index | Full index
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181       © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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185GRASS 8.2.1                                                 i.ortho.rectify(1)
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