1g.gui.image2target(1)         Grass User's Manual        g.gui.image2target(1)
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NAME

6       g.gui.image2target   -  Georectifies  a  map and allows managing Ground
7       Control Points for 3D correction.
8

KEYWORDS

10       imagery, aerial, photo, georectification, GCP, GUI
11

SYNOPSIS

13       g.gui.image2target
14       g.gui.image2target --help
15       g.gui.image2target  [--help]  [--verbose]  [--quiet]  [--ui]
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17   Flags:
18       --help
19           Print usage summary
20
21       --verbose
22           Verbose module output
23
24       --quiet
25           Quiet module output
26
27       --ui
28           Force launching GUI dialog
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DESCRIPTION

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
35       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
41       The GCP Manager must be started in the  target  location,  not  in  the
42       source location.
43
44       The GCP Manager is structured into three panels:
45
46           ·   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
53           ·   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
59   Components of the GCP Manager
60       Toolbars
61
62       Two toolbars are provided with the GCP Manager, one  for  managing  the
63       map displays and one for managing the GCP list.
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65       List of ground control points
66
67       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
74       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).
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79       Two panels for map display
80
81       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
86       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
90       Statusbar
91
92       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
97   GCP Map Display Toolbar
98           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
102           Re-render map
103           Re-renders both source and target canvas regardless of whether they
104           have changed or not.
105
106           Erase display
107           Erases both source and target canvas to a white background.
108
109           Define GCP (Ground Control Points)
110           On  left  mouse  click,  coordinates  are defined for the currently
111           selected GCP.
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113           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.
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120           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
124           defined  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
130           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
140           Adjust display zoom
141           Source and target display are adjusted by using  the  current  GCPs
142           for coordinate transformation:
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144       Adjust source display to target display
145           The  extents  of  the  source  display  are adjusted to the current
146           extents of the target display.
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148       Adjust target display to source display
149           The extents of the source  display  are  adjusted  to  the  current
150           extents of the target display.
151
152       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.
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158           Return to previous zoom
159           Returns to the previous zoom extent. Up to 10 levels of  zoom  back
160           are maintained.
161
162         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
166         Settings
167           Shows a settings dialog for GCP management and display:
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169       Symbology
170           Settings for map and GCP display:
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172       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
176       Factor for RMS error threshold = M + SD * factor:
177           All  GCPs  with  an  RMS  error larger than mean RMS + RMS standard
178           deviation * this factor will be displayed in  a  different  colour,
179           both  in  the  list  of  GCPs and the GCP Map Display. As a rule of
180           thumb, GCPs with an RMS error larger than M + SD * 2 are most prob‐
181           ably 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
185       Color
186           Set the color for GCPs on the GCP Map Display.
187
188       Color for high RMS error
189           Set  the  color  for GCPs with a high RMS error on the GCP Map Dis‐
190           play.
191
192       Color for selected GCP
193           Set the color for the currently selected GCP on the  GCP  Map  Dis‐
194           play.
195
196       Show unused GCPs
197           If unchecked, unused GCPs will not be shown on the GCP Map Display.
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199       Color for unused GCPs
200           Set the color for unused GCPs on the GCP Map Display.
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202       Symbol size
203           Set the symbol size for GCPs on the GCP Map Display.
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205       Line width
206           Set the line width for GCPs on the GCP Map Display.
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208       Select source map to display
209           Select a source map for the left pane of the GCP Map Display.
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211       Select target map to display
212           Select a target map for the right pane of the GCP Map Display.
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214       Rectification
215           Settings for georectification:
216
217       Select rectification method
218           Set the polynomial order for georectification. This order will also
219           be used for RMS error calculation.
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221       Clip to computational region in target location
222           Clip raster maps to the current computational region in the  target
223           location when georectifying.
224
225       Extension for output maps
226           Change  the  extension  for  output map names when doing the actual
227           georectification.
228
229         Show Help
230           Show help page for the GCP Manager.
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232         Quit
233           Quit the GCP Manager.
234
235   Toolbar for the GCP list
236         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.
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240         Add new GCP
241           Adds  a  new  Ground  Control  Point to the list and selects it for
242           editing.
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244         Delete selected GCP
245           Deletes the currently selected GCP from the list.
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247         Clear selected GCP
248           Resets all coordinates of the currently selected GCP to 0 (zero).
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250         Reload GCPs from POINTS file
251           Reloads GCPs from the imagery group’s POINTS file.
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253         Recalculate RMS error
254           Recalculates forward and backward RMS error for all GCP marked  for
255           use (activated checkbox in first row).
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257         Georectify
258           Uses  i.rectify  to  georectify  all  images  in the source imagery
259           group.
260
261   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.
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266       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
271       If RMS error is selected, the overall forward and backward RMS error is
272       displayed.
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SEE ALSO

275        wxGUI
276       wxGUI components
277
278        i.rectify, m.transform, v.rectify
279
280       See also video tutorials on GRASS Wiki.
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AUTHORS

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
287       $Date: 2017-11-03 18:21:39 +0100 (Fri, 03 Nov 2017) $
288

SOURCE CODE

290       Available at: wxGUI GCP Manager source code (history)
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292       Main index | GUI index | Topics index  |  Keywords  index  |  Graphical
293       index | Full index
294
295       © 2003-2019 GRASS Development Team, GRASS GIS 7.6.0 Reference Manual
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299GRASS 7.6.0                                              g.gui.image2target(1)
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