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 g.gui.photo2image and the recti‐
76 fication parameters created by g.gui.image2target. Rectification is
77 the process by which the geometry of an image is made planimetric.
78 This is accomplished by mapping an image from one coordinate system to
79 another. In i.photo.rectify the parameters computed by g.gui.photo2im‐
80 age and g.gui.image2target are used in equations to convert x,y image
81 coordinates to standard map coordinates for each pixel in the image.
82 The result is an image with a standard map coordinate system, compen‐
83 sated for relief distortions and photographic tilt. Upon completion of
84 the program the rectified image is deposited in a previously targeted
85 GRASS LOCATION.
86 Images can be resampled with various different interpolation methods:
88 nearest neighbor assignment, bilinear and bicubic interpolation. The
89 bilinear and bicubic interpolation methods are also available with a
90 fallback option. These methods "fall back" to simpler interpolation
91 methods along NULL borders. That is, from bicubic to bilinear to near‐
92 est.
93 The process may take an hour or more depending on the size of the im‐
95 age, the speed of the computer, the number files, and the size and res‐
96 olution of the selected window.
97 The rectified image will be located in the target LOCATION when the
99 program is completed. The original unrectified files are not modified
100 or removed.
101 The optional angle output holds the camera angle in degrees to the lo‐
103 cal surface, considering local slope and aspect. A value of 90 degrees
104 indicates that the camera angle was orthogonal to the local surface, a
105 value of 0 degrees indicates that the camera angle was parallel to the
106 local surface and negative values indicate that the surface was invisi‐
107 ble to the camera. As a rule of thumb, values below 30 degrees indicate
108 problem areas where the orthorectified output will appear blurred. Be‐
109 cause terrain shadowing effects are not considered, areas with high
110 camera angles may also appear blurred if they are located (viewed from
111 the camera position) behind mountain ridges or peaks.
112 i.photo.rectify can be run directly, specifying options in the command
114 line or the GUI, or it can be invoked as OPTION 8 through i.or‐
115 tho.photo. If invoked though i.ortho.photo, an interactive terminal is
116 used to determine the options.
117 Interactive mode
119 You are first asked if all images within the imagery group should be
120 rectified. If this option is not chosen, you are asked to specify for
121 each image within the imagery group whether it should be rectified or
122 not.
123 More than one file may be rectified at a time. Each file should have a
125 unique output file name. The next prompt asks you for an extension to
126 be appended to the rectified images.
127 The next prompt will ask you whether a camera angle map should be pro‐
129 duced and if yes, what should be its name.
130 After that you are asked if overwriting existing maps in the target lo‐
132 cation and mapset should be allowed.
133 The next prompt asks you to select one of two windows:
135 Please select one of the following options
137 1. Use the current window in the target location
138 2. Determine the smallest window which covers the image
139 >
140 If you choose option 2, you can also specify a desired target resolu‐
142 tion.
143 i.photo.rectify will only rectify that portion of the image that occurs
145 within the chosen window. Only that portion will be relocated in the
146 target database. It is therefore important to check the current window
147 in the target LOCATION if choice number one is selected.
148 Next you are asked to select an interpolation method.
150 Please select one of the following interpolation methods
151 1. nearest neighbor
152 2. bilinear
153 3. bicubic
154 4. bilinear with fallback
155 5. bicubic with fallback
156 >
157 The last prompt will ask you about the amount of memory to be used by
159 i.photo.rectify.
160
162 i.ortho.photo
163 i.ortho.camera
164 g.gui.photo2image
165 g.gui.image2target
166 i.ortho.init
167 i.rectify
168
170 Mike Baba, DBA Systems, Inc.
171 Updated rectification and elevation map to FP 1/2002 Markus Neteler
172 Bugfixes and enhancements 12/2010 Markus Metz
173
175 Available at: i.ortho.rectify source code (history)
176 Accessed: Saturday Oct 28 18:19:11 2023
178 Main index | Imagery index | Topics index | Keywords index | Graphical
180 index | Full index
181 © 2003-2023 GRASS Development Team, GRASS GIS 8.3.1 Reference Manual
183GRASS 8.3.1 i.ortho.rectify(1)