1i.ortho.rectify(1) Grass User's Manual i.ortho.rectify(1)
2
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 Amount of memory to use in MB
58 Default: 300
59 method=string
61 Interpolation method to use
62 Options: nearest, linear, cubic, lanczos, linear_f, cubic_f, lanc‐
63 zos_f
64 Default: nearest
65 angle=name
67 Raster map with camera angle relative to ground surface
68
70 i.photo.rectify rectifies an image by using the image to photo coordi‐
71 nate transformation matrix created by i.photo.2image and the rectifica‐
72 tion parameters created by i.photo.2target. Rectification is the
73 process by which the geometry of an image is made planimetric. This is
74 accomplished by mapping an image from one coordinate system to another.
75 In i.photo.rectify the parameters computed by i.photo.2image and
76 i.photo.2target are used in equations to convert x,y image coordinates
77 to standard map coordinates for each pixel in the image. The result is
78 an image with a standard map coordinate system, compensated for relief
79 distortions and photographic tilt. Upon completion of the program the
80 rectified image is deposited in a previously targeted GRASS LOCATION.
81 Images can be resampled with various different interpolation methods:
83 nearest neighbor assignment, bilinear and bicubic interpolation. The
84 bilinear and bicubic interpolation methods are also available with a
85 fallback option. These methods "fall back" to simpler interpolation
86 methods along NULL borders. That is, from bicubic to bilinear to near‐
87 est.
88 The process may take an hour or more depending on the size of the
90 image, the speed of the computer, the number files, and the size and
91 resolution of the selected window.
92 The rectified image will be located in the target LOCATION when the
94 program is completed. The original unrectified files are not modified
95 or removed.
96 The optional angle output holds the camera angle in degrees to the
98 local surface, considering local slope and aspect. A value of 90
99 degrees indicates that the camera angle was orthogonal to the local
100 surface, a value of 0 degrees indicates that the camera angle was par‐
101 allel to the local surface and negative values indicate that the sur‐
102 face was invisible to the camera. As a rule of thumb, values below 30
103 degrees indicate problem areas where the orthorectified output will
104 appear blurred. Because terrain shadowing effects are not considered,
105 areas with high camera angles may also appear blurred if they are
106 located (viewed from the camera position) behind mountain ridges or
107 peaks.
108 i.photo.rectify can be run directly, specifying options in the command
110 line or the GUI, or it can be invoked as OPTION 8 through
111 i.ortho.photo. If invoked though i.ortho.photo, an interactive terminal
112 is used to determine the options.
113 Interactive mode
115 You are first asked if all images within the imagery group should be
116 rectified. If this option is not chosen, you are asked to specify for
117 each image within the imagery group whether it should be rectified or
118 not.
119 More than one file may be rectified at a time. Each file should have a
121 unique output file name. The next prompt asks you for an extension to
122 be appended to the rectified images.
123 The next prompt will ask you whether a camera angle map should be pro‐
125 duced and if yes, what should be its name.
126 After that you are asked if overwriting existing maps in the target
128 location and mapset should be allowed.
129 The next prompt asks you to select one of two windows:
131 Please select one of the following options
133 1. Use the current window in the target location
134 2. Determine the smallest window which covers the image
135 >
136 If you choose option 2, you can also specify a desired target resolu‐
138 tion.
139 i.photo.rectify will only rectify that portion of the image that occurs
141 within the chosen window. Only that portion will be relocated in the
142 target database. It is therefore important to check the current window
143 in the target LOCATION if choice number one is selected.
144 Next you are asked to select an interpolation method.
146 Please select one of the following interpolation methods
147 1. nearest neighbor
148 2. bilinear
149 3. bicubic
150 4. bilinear with fallback
151 5. bicubic with fallback
152 >
153 The last prompt will ask you about the amount of memory to be used by
155 i.photo.rectify.
156
158 i.ortho.photo
159 i.ortho.camera
160 i.photo.2image
161 i.photo.2target
162 i.ortho.init
163 i.rectify
164
166 Mike Baba, DBA Systems, Inc.
167 Updated rectification and elevation map to FP 1/2002 Markus Neteler
168 Bugfixes and enhancements 12/2010 Markus Metz
169 Last changed: $Date: 2013-02-20 11:16:02 +0100 (Wed, 20 Feb 2013) $
171
173 Available at: i.ortho.rectify source code (history)
174 Main index | Imagery index | Topics index | Keywords index | Graphical
176 index | Full index
177 © 2003-2019 GRASS Development Team, GRASS GIS 7.6.0 Reference Manual
179GRASS 7.6.0 i.ortho.rectify(1)