1i.ortho.photo(1) Grass User's Manual i.ortho.photo(1)
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6 i.ortho.photo - Menu driver for the photo imagery programs.
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9 imagery
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12 i.ortho.photo
13 i.ortho.photo help
14 i.ortho.photo group=name [--verbose] [--quiet]
15 Parameters:
17 group=name
18 Name of imagery group for ortho-rectification
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21 i.ortho.photo allows the user to ortho-rectify imagery group files. An
22 imagery group consists of several scanned aerial photographs (raster
23 maps) of a common area. Imagery groups can be created or modified
24 using the GRASS Image Processing Program i.group, or using the first
25 menu option described below. i.ortho.photo guides the user through the
26 steps required to ortho-rectify the raster maps in a single imagery
27 group.
28 The first menu in i.ortho.photo provides the user with the following
30 options:
31 Initialization Options:
33 1) Select/Modify imagery group
34 2) Select/Modify imagery group target
35 3) Select/Modify target elevation model
36 4) Select/Modify imagery group camera
37 Transformation Parameter Computation:
39 5) Compute image-to-photo transformation parameters
40 6) Initialize exposure station parameters
41 7) Compute photo-to-target transformation parameters
42 Ortho-rectification Option:
44 8) Ortho-rectify imagery group raster maps
45 RETURN to exit
47 >
48 To ortho-rectify aerial images the user has to follow the menu options
50 step by step. Generally the user builds a target location containing a
51 projected DEM and a map reference (topo sheet or other map). Another
52 xy-location will contain the aerial photo. The entire rectification
53 process is started within the xy-location. First the target to the pro‐
54 jected location has to be set (i.target), then the image references
55 (fiducial points) will be defined. After describing the camera parame‐
56 ters, reference points from aerial image to the topo sheet from the
57 target location will be set. The local elevation will be taken from the
58 target DEM. Finally the aerial image will be rectified.
59 The options to follow are described as follows:
61 1. Select/Modify imagery group
63 The current imagery group is display at the top of the previous
64 menu. You may select another (new or existing) imagery group
65 for the ortho-rectification program using option (1). After
66 choosing option (1) you will be prompted for the name of a new
67 or existing imagery group. Option (1) using the GRASS Image
68 Processing Program i.group, for creation or modification of
69 imagery groups. For more information on imagery group creation
70 or modification please the the GRASS manual page for i.group.
71 2. Select/Modify imagery group target
73 The target location and mapset may be selected or modified using
74 option (2). After choosing option (2) you will be prompted for
75 the names of the target location and mapset, where the ortho-
76 rectified raster maps will reside. The target location is also
77 the location from which the elevation model (raster map) will be
78 selected -- see option (3). Option (2) uses the GRASS Image
79 Processing Program i.target, for selection or modification of
80 the imagery group target location and mapset. For more informa‐
81 tion on imagery group selection or modification please the the
82 GRASS manual page for i.target.
83 3. Select/Modify target elevation model
85 Option (3) allows you to select the raster map from the target
86 location to be used as the elevation model. The elevation model
87 is required for both the computation of photo-to-target parame‐
88 ters (option 6) and for the ortho-rectification of the imagery
89 group files (option 8). The raster map select for the elevation
90 model should cover the entire area of the image group to be
91 ortho-rectified. Currently, the elevation model raster map is
92 expected to be in units of meters. DTED and DEM files are suit‐
93 able for use as the elevation model in the ortho-rectification
94 program. After selection option (3) you will be prompted for
95 the name of the raster map in the target location that you want
96 to use as the elevation model.
97 4. Select/Modify imagery group camera
99 Using option (4) you may select or create an camera reference
100 file that will be used with the current imagery group. A camera
101 reference file contains information on the internal characteris‐
102 tics of the aerial camera, as well as the geometry of the fidu‐
103 cial or reseau marks. The most important characteristic of the
104 camera is its focal length. Fiducial or reseau marks locations
105 are required to compute the scanned image to photo-coordinate
106 transformation parameter (option 5). For a more detailed
107 description of option (4) please see the GRASS manual page for
108 photo.camera.
109 5. Compute image-to-photo transformation parameters
111 The scanned image to photo-coordinate transformation parameters
112 are computed using option (5). In this interactive option you
113 associate scanned reference points (fiducials, reseau marks,
114 etc.) with their known photo coordinates from the camera refer‐
115 ence file. Complete documentation for this option is available
116 under the manual entry photo.2image.
117 6. Initialize exposure station parameters
119 If option (6) is selected, initial camera exposure station
120 parameters and initial variances may be selected or modified.
121 Complete documentation for this option is available under the
122 manual entry photo.init.
123 7. Compute photo-to-target transformation parameters
125 The photo to target transformation parameters are compute using
126 option (7). Here control points are marked on one or more
127 imagery group files and associated with there known standard
128 (e.g. UTM) and elevation coordinates. Complete documentation
129 for this option is available under the manual entry photo.2tar‐
130 get.
131 8. Ortho-photo imagery group files
133 Option (8) is used to perform the actual image ortho-rectifica‐
134 tion after all of the transformation parameters have been com‐
135 puted. Ortho-rectified raster files will be created in the tar‐
136 get location for each selected imagery group file. You may
137 select either the current window in the target location or the
138 minimal bounding window for the ortho-rectified image. Complete
139 documentation for this option is available under the manual
140 entry photo.rectify.
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143 i.ortho.photo currently requires the elevation model to be in meters,
144 and the target location to be a standard (e.g. UTM) coordinate system.
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147 photo.camera, photo.2image, photo.2target, photo.init, photo.rectify
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150 Mike Baba, DBA Systems, Inc.
151 Updated rectification and elevation map to FP 1/2002 Markus Neteler
153 Last changed: $Date: 2007-02-15 07:23:34 +0100 (Thu, 15 Feb 2007) $
155 Full index
157 © 2003-2008 GRASS Development Team
159GRASS 6.3.0 i.ortho.photo(1)