1g.gui.image2target(1) GRASS GIS User's Manual g.gui.image2target(1)
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6 g.gui.image2target - Georectifies a map and allows managing Ground
7 Control Points for 3D correction.
8
10 imagery, GUI, aerial, photo, georectification, geometry, GCP
11
13 g.gui.image2target
14 g.gui.image2target --help
15 g.gui.image2target [--help] [--verbose] [--quiet] [--ui]
16 Flags:
18 --help
19 Print usage summary
20 --verbose
22 Verbose module output
23 --quiet
25 Quiet module output
26 --ui
28 Force launching GUI dialog
29
31 The GCP Manager is a wxGUI extension which allows the user to create,
32 edit, and manage Ground Control Points. It is available from the menu
33 "File | Manage Ground Control Points".
34 The GCP Manager provides an interactive graphical interface to manage
36 and analyze Ground Control Points. A backup copy of the initial POINTS
37 file is always maintained and updated only on request (Save GCPs to
38 POINTS file). This guarantees that accidental changes are not permanent
39 and can be undone by reloading the Ground Control Points.
40 The GCP Manager must be started in the target location, not in the
42 source location.
43 The GCP Manager is structured into three panels:
45 • The topmost panel shows a list of Ground Control Points. Tools
47 to manipulate and analyze GCPs are provided in the toolbar.
48 This panel can be moved out of the GCP manager window by either
49 dragging with the caption or by clicking on the pin button on
50 the right in the caption. This panel can also be placed below
51 the map displays by dragging.
52 • The two panels in the lower part are used for map and GCP dis‐
54 play, the left pane showing a map from the source location and
55 the right pane showing a reference map from the target loca‐
56 tion. Numbered Ground Control Points are shown on both map dis‐
57 plays.
58 Components of the GCP Manager
60 Toolbars
61 Two toolbars are provided with the GCP Manager, one for managing the
63 map displays and one for managing the GCP list.
64 List of ground control points
66 The list of Ground Control Points can be sorted by clicking on a column
68 header. Clicking on a cloumn header will sort the GCPs ascending, a
69 second click on the same column will sort the GCPs descending. Overall
70 RMS error and individual RMS errors of all points are often improved if
71 the GCP with the highest RMS error is adjusted. Individual coordinates
72 can be edited by double-clicking on a row.
73 The first column holds a checkbox and displays the point number. A GCP
75 is only used for RMS error calculation and georectification if its
76 checkbox on the left is checked. Uncheck to deactivate a GCP (mark as
77 unused GCP).
78 Two panels for map display
80 The left panel is used to display a map from the source location, the
82 right panel to display a map from the target loaction. Zooming in and
83 out is always possible with the mouse wheel and done for each map can‐
84 vas separately.
85 GCPs are displayed in different colors, depending on whether a GCP has
87 a high RMS error, is currently unused or is currently selected. Option‐
88 ally, currently unused GCPs are not shown on the map display.
89 Statusbar
91 At the bottom of the GCP Manager is a statusbar providing several func‐
93 tions. The default is set to Go to GCP No. (see also below). Typing a
94 number or using the up/down arrows will center the maps on the given
95 GCP, useful with a high zoom.
96 GCP Map Display Toolbar
98 Â Display map
99 Displays maps for source and target canvas and re-renders any lay‐
100 ers that have changed since the last time the display was updated.
101 Â Re-render map
103 Re-renders both source and target canvas regardless of whether they
104 have changed or not.
105 Â Erase display
107 Erases both source and target canvas to a white background.
108 Â Define GCP (Ground Control Points)
110 On left mouse click, coordinates are defined for the currently se‐
111 lected GCP.
112 Â Pan
114 Interactive selection of a new center of view in the active display
115 monitor. Drag the pan cursor while pressing the left mouse button
116 to pan. Alternatively left-click on the new center. Panning changes
117 the location of the region displayed but not the size of the area
118 displayed or the resolution.
119 Â Zoom in
121 Interactive zooming with the mouse in the active map canvas (source
122 or target). Drawing a box or just a left click with the mouse and
123 zoom-in cursor causes the display to zoom in so that the area de‐
124 fined by the box fills the display. The map resolution is not
125 changed. Clicking with the zoom-in cursor causes the display to
126 zoom in by 30%, centered on the point where the mouse is clicked.
127 Zooming changes the display region extents (both size and location
128 of area displayed).
129 Â Zoom out
131 Interactive zooming with the mouse in the active map canvas (source
132 or target). Drawing a box or just a left click with the mouse and
133 zoom-out cursor causes the display to zoom out so that the area
134 displayed shrinks to fill the area defined by the box. The map res‐
135 olution is not changed. Clicking with the zoom-out cursor causes
136 the display to zoom out by 30%, centered on the point where the
137 mouse is clicked. Zooming changes the display region extents (both
138 size and location of area displayed).
139 Â Adjust display zoom
141 Source and target display are adjusted by using the current GCPs
142 for coordinate transformation:
143 Adjust source display to target display
145 The extents of the source display are adjusted to the current ex‐
146 tents of the target display.
147 Adjust target display to source display
149 The extents of the source display are adjusted to the current ex‐
150 tents of the target display.
151 Set active map canvas
153 Sets the currently active map canvas (source or target). Click to
154 set active map canvas for Return to previous zoom or Zoom to extent
155 of currently displayed map. Alternatively, move the mouse over the
156 map canvas to be used as active canvas.
157 Â Return to previous zoom
159 Returns to the previous zoom extent. Up to 10 levels of zoom back
160 are maintained.
161 Â Zoom to extent of currently displayed map
163 Zoom to the extent of the currently displayed map in the active map
164 canvas (source or target).
165 Â Settings
167 Shows a settings dialog for GCP management and display:
168 Symbology
170 Settings for map and GCP display:
171 Highlight highest RMS error only
173 Only the GCP with the highest RMS error will be displayed in a dif‐
174 ferent colour, both in the list of GCPs and the GCP Map Display.
175 Factor for RMS error threshold = M + SD * factor:
177 All GCPs with an RMS error larger than mean RMS + RMS standard de‐
178 viation * this factor will be displayed in a different colour, both
179 in the list of GCPs and the GCP Map Display. As a rule of thumb,
180 GCPs with an RMS error larger than M + SD * 2 are most probably
181 wrong. GCPs with an RMS error larger than M + SD * 1 are worth
182 closer inspection. This option is only available if Highlight high‐
183 est RMS error only is unchecked.
184 Color
186 Set the color for GCPs on the GCP Map Display.
187 Color for high RMS error
189 Set the color for GCPs with a high RMS error on the GCP Map Dis‐
190 play.
191 Color for selected GCP
193 Set the color for the currently selected GCP on the GCP Map Dis‐
194 play.
195 Show unused GCPs
197 If unchecked, unused GCPs will not be shown on the GCP Map Display.
198 Color for unused GCPs
200 Set the color for unused GCPs on the GCP Map Display.
201 Symbol size
203 Set the symbol size for GCPs on the GCP Map Display.
204 Line width
206 Set the line width for GCPs on the GCP Map Display.
207 Select source map to display
209 Select a source map for the left pane of the GCP Map Display.
210 Select target map to display
212 Select a target map for the right pane of the GCP Map Display.
213 Rectification
215 Settings for georectification:
216 Select rectification method
218 Set the polynomial order for georectification. This order will also
219 be used for RMS error calculation.
220 Clip to computational region in target location
222 Clip raster maps to the current computational region in the target
223 location when georectifying.
224 Extension for output maps
226 Change the extension for output map names when doing the actual
227 georectification.
228 Â Show Help
230 Show help page for the GCP Manager.
231 Â Quit
233 Quit the GCP Manager.
234 Toolbar for the GCP list
236 Â Save GCPs to POINTS file
237 The current list of GCPs is saved to the imagery group’s POINTS
238 file and to a backup copy.
239 Â Add new GCP
241 Adds a new Ground Control Point to the list and selects it for
242 editing.
243 Â Delete selected GCP
245 Deletes the currently selected GCP from the list.
246 Â Clear selected GCP
248 Resets all coordinates of the currently selected GCP to 0 (zero).
249 Â Reload GCPs from POINTS file
251 Reloads GCPs from the imagery group’s POINTS file.
252 Â Recalculate RMS error
254 Recalculates forward and backward RMS error for all GCP marked for
255 use (activated checkbox in first row).
256 Â Georectify
258 Uses i.rectify to georectify all images in the source imagery
259 group.
260 GCP Map Display Statusbar
262 The GCP map display statusbar is similar to the statusbar in the regu‐
263 lar GRASS GIS map display with two differences, Go to has been replaced
264 with Go to GCP No. and Projection has been replaced with RMS error.
265 If Go to GCP No. is selected, a GCP number can be given in the left
267 side of the statusbar and the source and target map canvas will be cen‐
268 tered on the given GCP. Clicking on the map canvas will update coordi‐
269 nates for this GCP.
270 If RMS error is selected, the overall forward and backward RMS error is
272 displayed.
273
275 wxGUI
276 wxGUI components
277 i.rectify, m.transform, v.rectify
279 See also video tutorials on GRASS Wiki.
281
283 Markus Metz
284 Based on the Georectifier (GRASS 6.4.0) by Michael Barton
285 Martin Landa, Czech Technical University in Prague, Czech Republic
286
288 Available at: wxGUI GCP Manager source code (history)
289 Accessed: Saturday Jan 21 21:18:00 2023
291 Main index | GUI index | Topics index | Keywords index | Graphical in‐
293 dex | Full index
294 © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
296GRASS 8.2.1 g.gui.image2target(1)