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 [-ca] 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 --overwrite
29 Allow output files to overwrite existing files
30 --help
32 Print usage summary
33 --verbose
35 Verbose module output
36 --quiet
38 Quiet module output
39 --ui
41 Force launching GUI dialog
42 Parameters:
44 group=name [required]
45 Name of input imagery group
46 input=name[,name,...]
48 Name of input raster map(s)
49 extension=string [required]
51 Output raster map(s) suffix
52 resolution=float
54 Target resolution (ignored if -c flag used)
55 memory=memory in MB
57 Maximum memory to be used (in MB)
58 Cache size for raster rows
59 Default: 300
60 method=string
62 Interpolation method to use
63 Options: nearest, linear, cubic, lanczos, linear_f, cubic_f, lanc‐
64 zos_f
65 Default: nearest
66 angle=name
68 Raster map with camera angle relative to ground surface
69
71 i.photo.rectify rectifies an image by using the image to photo coordi‐
72 nate transformation matrix created by i.photo.2image and the rectifica‐
73 tion parameters created by i.photo.2target. Rectification is the
74 process by which the geometry of an image is made planimetric. This is
75 accomplished by mapping an image from one coordinate system to another.
76 In i.photo.rectify the parameters computed by i.photo.2image and
77 i.photo.2target are used in equations to convert x,y image coordinates
78 to standard map coordinates for each pixel in the image. The result is
79 an image with a standard map coordinate system, compensated for relief
80 distortions and photographic tilt. Upon completion of the program the
81 rectified image is deposited in a previously targeted GRASS LOCATION.
82 Images can be resampled with various different interpolation methods:
84 nearest neighbor assignment, bilinear and bicubic interpolation. The
85 bilinear and bicubic interpolation methods are also available with a
86 fallback option. These methods "fall back" to simpler interpolation
87 methods along NULL borders. That is, from bicubic to bilinear to near‐
88 est.
89 The process may take an hour or more depending on the size of the
91 image, the speed of the computer, the number files, and the size and
92 resolution of the selected window.
93 The rectified image will be located in the target LOCATION when the
95 program is completed. The original unrectified files are not modified
96 or removed.
97 The optional angle output holds the camera angle in degrees to the
99 local surface, considering local slope and aspect. A value of 90
100 degrees indicates that the camera angle was orthogonal to the local
101 surface, a value of 0 degrees indicates that the camera angle was par‐
102 allel to the local surface and negative values indicate that the sur‐
103 face was invisible to the camera. As a rule of thumb, values below 30
104 degrees indicate problem areas where the orthorectified output will
105 appear blurred. Because terrain shadowing effects are not considered,
106 areas with high camera angles may also appear blurred if they are
107 located (viewed from the camera position) behind mountain ridges or
108 peaks.
109 i.photo.rectify can be run directly, specifying options in the command
111 line or the GUI, or it can be invoked as OPTION 8 through
112 i.ortho.photo. If invoked though i.ortho.photo, an interactive terminal
113 is used to determine the options.
114 Interactive mode
116 You are first asked if all images within the imagery group should be
117 rectified. If this option is not chosen, you are asked to specify for
118 each image within the imagery group whether it should be rectified or
119 not.
120 More than one file may be rectified at a time. Each file should have a
122 unique output file name. The next prompt asks you for an extension to
123 be appended to the rectified images.
124 The next prompt will ask you whether a camera angle map should be pro‐
126 duced and if yes, what should be its name.
127 After that you are asked if overwriting existing maps in the target
129 location and mapset should be allowed.
130 The next prompt asks you to select one of two windows:
132 Please select one of the following options
134 1. Use the current window in the target location
135 2. Determine the smallest window which covers the image
136 >
137 If you choose option 2, you can also specify a desired target resolu‐
139 tion.
140 i.photo.rectify will only rectify that portion of the image that occurs
142 within the chosen window. Only that portion will be relocated in the
143 target database. It is therefore important to check the current window
144 in the target LOCATION if choice number one is selected.
145 Next you are asked to select an interpolation method.
147 Please select one of the following interpolation methods
148 1. nearest neighbor
149 2. bilinear
150 3. bicubic
151 4. bilinear with fallback
152 5. bicubic with fallback
153 >
154 The last prompt will ask you about the amount of memory to be used by
156 i.photo.rectify.
157
159 i.ortho.photo
160 i.ortho.camera
161 i.photo.2image
162 i.photo.2target
163 i.ortho.init
164 i.rectify
165
167 Mike Baba, DBA Systems, Inc.
168 Updated rectification and elevation map to FP 1/2002 Markus Neteler
169 Bugfixes and enhancements 12/2010 Markus Metz
170
172 Available at: i.ortho.rectify source code (history)
173 Main index | Imagery index | Topics index | Keywords index | Graphical
175 index | Full index
176 © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
178GRASS 7.8.5 i.ortho.rectify(1)