1wxGUI.vdigit(1)               Grass User's Manual              wxGUI.vdigit(1)
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wxGUI Vector Digitizer

DESCRIPTION

7       The  vector  digitizer  is  a  wxGUI component intended for interactive
8       editing and digitizing vector maps (see v.edit for non-interactive vec‐
9       tor editing GRASS capabilities).
10
11       Note  that  only  vector maps stored or generated in the current mapset
12       can be opened for editing.
13
14       The digitizer allows editing of 2D vector features (points, lines, cen‐
15       troids, boundaries, and areas).
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17       Vector  features  can  be  selected by mouse (bounding box or simply by
18       mouse  click,  see  select  threshold  in   Settings→General→Select
19       threshold),  or  by  query  (eg.  by  line length, see Settings→Query
20       Tool).
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22   STARTING THE DIGITIZER
23       The vector digitizer can  be  launched  from  Map  Display  toolbar  by
24       selecting  "Digitize" from Tools combobox. Vector map is selectable for
25       editing from Digitizer toolbar ("Select vector map" combobox, note that
26       only  vector  maps  from  the  current  layer tree in Layer Manager are
27       listed).  The vector digitizer can alternatively be activated from  the
28       contextual  menu  in  the Layer Manager by selecting "Start editing" on
29       selected vector map in the layer tree, or directly from the Layer  Man‐
30       ager toolbar .  The vector digitizer also can also be launched from the
31       command line as a stand-alone application g.gui.vdigit.
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33   CREATING A NEW VECTOR MAP
34       A new vector map can be easily created from the  digitizer  toolbar  by
35       selecting  "New vector map" in "Select vector map" combobox. A new vec‐
36       tor map is created, added to the current layer tree  in  Layer  Manager
37       and  opened  for editing. "Select vector map" combobox in the digitizer
38       toolbar also allows easily switching between vector maps to be edited.
39
40   EDITING AN EXISTING VECTOR MAP
41       An existing vector map selected in the digitizer toolbar in the "Select
42       vector  map" combobox. This map is then opened for editing and added to
43       the current layer tree in the Layer Manager. This "Select  vector  map"
44       combobox  in the digitizer toolbar also allows to easily switch between
45       vector maps to be edited.
46
47   USING A RASTER BACKGROUND MAP
48       In order to digitize from a raster map, simply load the  map  into  the
49       Map  Display  using the Layer Manager. Then start digitizing, see below
50       for details.
51
52   USING A VECTOR BACKGROUND MAP
53       The vector digitizer allows you to select a  "background"  vector  map.
54       Loading it within the digitizer is different from simply loading it via
55       Layer Manager since direct interaction with single vector features then
56       becomes possible.
57       Vector features may be copied from the background map by "Copy features
58       from (background) vector map" tool from the "Additional tools"  of  the
59       digitizer  toolbar.  Newly digitized vector features are snapped in the
60       given threshold to the features from the background map.
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62   DIGITIZER TOOLBAR
63             Digitize new point
64           Add new point to vector map and optionally define its attributes.
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66             Digitize new line
67           Add new line to vector map and optionally define its attributes.
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69             Digitize new boundary
70           Add  new  boundary  to  vector  map  and  optionally   define   its
71           attributes.
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73             Digitize new centroid
74           Add   new   centroid  to  vector  map  and  optionally  define  its
75           attributes.
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77             Digitize new area
78           Add new area (closed boundary and one centroid  inside)  to  vector
79           map and optionally define its attributes.
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81             Move vertex
82           Move  selected  vertex of linear feature. Thus shape of linear fea‐
83           ture is changed.
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85             Add vertex
86           Add new vertex to selected linear feature (shape not changed).
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88             Remove vertex
89           Remove selected vertex from linear feature. Thus shape of  selected
90           feature can be changed.
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92             Edit line/boundary
93           Edit  selected  linear feature, add new segments or remove existing
94           segments of linear feature.
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96             Move feature(s)
97           Move selected vector features. Selection can be done by mouse or by
98           query.
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100             Delete feature(s)
101           Delete  selected  vector features (point, line, centroid, or bound‐
102           ary). Selection can be done by mouse or by query.
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104             Delete areas(s)
105           Delete selected vector areas. Selection can be done by mouse or  by
106           query.
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108             Display/update categories
109           Display  categories  of  selected vector feature. Category settings
110           can be modified, new layer/category pairs added or already  defined
111           pairs removed.
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113             Display/update attributes
114           Display  attributes  of selected vector feature (based on its cate‐
115           gory settings).  Attributes can be also modified. Same  functional‐
116           ity  is  accessible  from  Main toolbar "Query vector map (editable
117           mode)".
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119             Additional tools
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121           ·   Break selected lines/boundaries at intersection
122               Split given vector line or boundary into  two  lines  on  given
123               position (based on v.clean, tool=break).
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125           ·   Connect two selected lines/boundaries
126               Connect  selected  lines or boundaries, the first given line is
127               connected to the second one. The second line is broken if  nec‐
128               essary  on  each intersection.  The lines are connected only if
129               distance between them is not greater  than  snapping  threshold
130               value.
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132           ·   Copy categories
133               Copy category settings of selected vector feature to other vec‐
134               tor features. Layer/category pairs of  source  vector  features
135               are  appended to the target feature category settings. Existing
136               layer/category pairs are not removed from category settings  of
137               the target features.
138
139           ·   Copy features from (background) vector map
140               Make  identical  copy  of  selected vector features. If a back‐
141               ground vector map has been selected  from  the  Layer  Manager,
142               copy  features  from  background  vector map, not from the cur‐
143               rently modified vector map.
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145           ·   Copy attributes
146               Duplicate attributes settings of  selected  vector  feature  to
147               other  vector  features.  New  category(ies) is appended to the
148               target feature  category  settings  and  attributes  duplicated
149               based  on category settings of source vector features. Existing
150               layer/category pairs are not removed from category settings  of
151               the target features.
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153           ·   Feature type conversion
154               Change  feature  type of selected geometry features. Points are
155               converted to centroids, centroids to points,  lines  to  bound‐
156               aries and boundaries to lines.
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158           ·   Flip selected lines/boundaries
159               Flip  direction  of  selected  linear features (lines or bound‐
160               aries).
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162           ·   Merge selected lines/boundaries
163               Merge (at least two) selected vector lines or  boundaries.  The
164               geometry of the merged vector lines can be changed. If the sec‐
165               ond line from two selected lines is in  opposite  direction  to
166               the  first,  it  will be flipped. See also module v.build.poly‐
167               lines.
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169           ·   Snap selected lines/boundaries (only to nodes)
170               Snap vector  features  in  given  threshold.  See  also  module
171               v.clean.  Note  that this tool supports only snapping to nodes.
172               Snapping to vector features from background vector map  is  not
173               currently supported.
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175           ·   Split line/boundary
176               Split selected line or boundary on given position.
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178           ·   Query tool
179               Select  vector  features  by  defining  a threshold for min/max
180               length value (linear features or dangles).
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182           ·   Z-bulk labeling of 3D lines
183               Assign z coordinate values to 3D vector lines in bounding  box.
184               This is useful for labeling contour lines.
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186             Undo
187           Undo previous operations.
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189             Redo
190           Redo previous operations.
191
192             Settings
193           Digitizer settings.
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195             Quit digitizing tool
196           Changes  in  vector map can be optionally discarded when digitizing
197           session is quited.
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NOTES

200       Mouse button functions:
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202       Left   - select or deselect features
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204       Control+Left - cancel action or undo vertex when digitizing lines
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206       Right  - confirm action
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208       Dead (deleted) features are only marked as ’dead’ in the geometry  file
209       but remain there and occupy space. Any vector module used afterwards on
210       this vector map which really reads and writes vector geometry  (so  not
211       g.copy) will write only features which are ’alive’.
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213       Added  or  modified vector features are snapped to existing vector fea‐
214       tures (Settings→General→Snapping).  To  disable  snapping  set  the
215       snapping threshold to ’0’.
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217       If the digitizer crashes for some reason, the changes are automatically
218       saved. Broken topology can be repaired by running v.build.
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220       GRASS GIS uses a topological  vector  format,  meaning  that  a  common
221       boundary  of two polygons is only stored once. When digitizing polygons
222       it is thus important to be able to only draw each boundary  once.  When
223       drawing  a  polygon  adjacent  to an existing polygon, one has to first
224       split the existing boundary at the points where the new  boundary  will
225       be  attached.  Snapping should be set to ensure that the new boundaries
226       are automatically attached to the chosen points.
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REFERENCES

229           ·   GRASS Vedit Library
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231           ·   Vector Database Management (Wiki page)
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SEE ALSO

234        wxGUI
235       wxGUI components
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237        v.edit, v.category, v.build, wxGUI.rdigit
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239       See also the WxGUI Vector Digitizer Wiki page including  video  tutori‐
240       als.
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AUTHOR

243       Martin  Landa, FBK-irst (2007-2008), Trento, Italy, and Czech Technical
244       University in Prague, Czech Republic
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SOURCE CODE

247       Available at: wxGUI Vector Digitizer source code (history)
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249       Main index | GUI index | Topics index  |  Keywords  index  |  Graphical
250       index | Full index
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252       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual
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256GRASS 7.8.2                                                    wxGUI.vdigit(1)
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