1i.ortho.rectify(1) GRASS GIS User's Manual i.ortho.rectify(1)
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6 i.ortho.rectify - Orthorectifies an image by using the image to photo
7 coordinate transformation matrix.
8
10 imagery, orthorectify
11
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 Flags:
21 -c
22 Use current region settings in target location (def.=calculate
23 smallest area)
24 -a
26 Rectify all raster maps in group
27 -p
29 Enable panorama camera correction
30 --overwrite
32 Allow output files to overwrite existing files
33 --help
35 Print usage summary
36 --verbose
38 Verbose module output
39 --quiet
41 Quiet module output
42 --ui
44 Force launching GUI dialog
45 Parameters:
47 group=name [required]
48 Name of input imagery group
49 input=name[,name,...]
51 Name of input raster map(s)
52 extension=string [required]
54 Output raster map(s) suffix
55 resolution=float
57 Target resolution (ignored if -c flag used)
58 memory=memory in MB
60 Maximum memory to be used (in MB)
61 Cache size for raster rows
62 Default: 300
63 method=string
65 Interpolation method to use
66 Options: nearest, linear, cubic, lanczos, linear_f, cubic_f, lanc‐
67 zos_f
68 Default: nearest
69 angle=name
71 Raster map with camera angle relative to ground surface
72
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 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 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.
96 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 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.
111 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.
116 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 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.
126 The next prompt will ask you whether a camera angle map should be pro‐
128 duced and if yes, what should be its name.
129 After that you are asked if overwriting existing maps in the target lo‐
131 cation and mapset should be allowed.
132 The next prompt asks you to select one of two windows:
134 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 If you choose option 2, you can also specify a desired target resolu‐
141 tion.
142 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.
147 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 The last prompt will ask you about the amount of memory to be used by
158 i.photo.rectify.
159
161 i.ortho.photo
162 i.ortho.camera
163 i.photo.2image
164 i.photo.2target
165 i.ortho.init
166 i.rectify
167
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
174 Available at: i.ortho.rectify source code (history)
175 Accessed: Saturday Jan 21 21:16:49 2023
177 Main index | Imagery index | Topics index | Keywords index | Graphical
179 index | Full index
180 © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
182GRASS 8.2.1 i.ortho.rectify(1)