Provided by: grass-doc_6.4.3-3_all 
NAME
wxGUI.Vector_Digitizer
DESCRIPTION
The vector digitizer is a wxGUI component intended for interactive editing vector maps
(see v.edit for non-interactive vector editing GRASS capabilities).
The digitizer supports editing of 2D vector features (points, lines, centroids,
boundaries, and area). Vector features can be selected using mouse or by query (e.g.
minimal vector line length). Vector features can be selected by bounding box or simply by
mouse click (based on 'Settings->General->Select threshold' value).
Vector digitizer can be activated from Main toolbar in Map Display by selecting "Digitize"
from "Tools" combobox. Vector map to be edited can be afterwards selected from digitizer
toolbar ("Select vector map" combobox, note that only vector maps from the current layer
tree in Layer Manager are available). Vector digitizer can be alternatively also
activated from contextual menu in Layer Manager by selecting "Start editing" on selected
vector map in the layer tree.
New vector map can be easily created from digitizer toolbar by selecting "New vector map"
in "Select vector map" combobox. A new vector map is created, added to the current layer
tree in Layer Manager and opened for editing. "Select vector map" combobox in digitizer
toolbar also allows switching easily between vector maps to be edited.
The wxGUI vector digitizer draws all maps in the Layer Manager in the Map Display window;
in addition, the digitizer also recognizes a special "background" vector map. This map is
selected from the Layer Manager by right-clicking on the map and selecting "Use as
Background Map" from the contextual menu. The features of the background map may then be
copied into the currently edited vector map using the "Copy features from (background)
vector map" button in the "Additional Tools" menu on the Digitzer Toolbar.
DIGITIZER TOOLBAR
Digitize new point
Add new point to vector map and optionally define its attributes.
Digitize new line
Add new line to vector map and optionally define its attributes.
Digitize new boundary
Add new boundary to vector map and optionally define its attributes.
Digitize new centroid
Add new centroid to vector map and optionally define its attributes.
Digitize new area
Add new area (closed boundary and one centroid inside) to vector map and optionally
define its attributes.
Move vertex
Move selected vertex of linear feature. Thus shape of linear feature is changed.
Add vertex
Add new vertex to selected linear feature (shape not changed).
Remove vertex
Remove selected vertex from linear feature. Thus shape of selected feature can be
changed.
Edit line/boundary
Edit selected linear feature, add new segments or remove existing segments of linear
feature.
Move feature(s)
Move selected vector features. Selection can be done by mouse or by query.
Delete feature(s)
Delete selected vector features (point, line, centroid, or boundary). Selection can be
done by mouse or by query.
Display/update categories
Display categories of selected vector feature. Category settings can be modified, new
layer/category pairs added or already defined pairs removed.
Display/update attributes
Display attributes of selected vector feature (based on its category settings).
Attributes can be also modified. Same functionality is accessible from Main toolbar
"Query vector map (editable mode)".
Additional tools
Break selected lines/boundaries at intersection
Split given vector line or boundary into two lines on given position (based on
v.clean, tool=break).
Connect two selected lines/boundaries
Connect selected lines or boundaries, the first given line is connected to the
second one. The second line is broken if necessary on each intersection. The
lines are connected only if distance between them is not greater than snapping
threshold value.
Copy categories
Copy category settings of selected vector feature to other vector features.
Layer/category pairs of source vector features are appended to the target
feature category settings. Existing layer/category pairs are not removed from
category settings of the target features.
Copy features from (background) map
Make identical copy of selected vector features. If a background vector map
has been selected from the Layer Manager, copy features from background vector
map, not from the currently modified vector map.
Copy attributes
Duplicate attributes settings of selected vector feature to other vector
features. New category(ies) is appended to the target feature category settings
and attributes duplicated based on category settings of source vector features.
Existing layer/category pairs are not removed from category settings of the
target features.
Feature type conversion
Change feature type of selected geometry features. Points are converted to
centroids, centroids to points, lines to boundaries and boundaries to lines.
Flip selected lines/boundaries
Flip direction of selected linear features (lines or boundaries).
Merge selected lines/boundaries
Merge (at least two) selected vector lines or boundaries. The geometry of the
merged vector lines can be changed. If the second line from two selected lines
is in opposite direction to the first, it will be flipped. See also module
v.build.polylines.
Snap selected lines/boundaries (only to nodes)
Snap vector features in given threshold. See also module v.clean. Note that
this tool supports only snapping to nodes. Snapping to vector features from
background vector map is not currently supported.
Split line/boundary
Split selected line or boundary on given position.
Query tool
Select vector features by defining a threshold for min/max length value (linear
features or dangles).
Z-bulk labeling of 3D lines
Assign z coordinate values to 3D vector lines in bounding box. This is useful
for labeling contour lines.
Undo
Undo previous operations.
Settings
Dialog for vector digitizer settings.
Quit digitizing tool
Changes in vector map can be optionally discarded when digitizing session is quited.
NOTES
Mouse button Functions:
Left - select/deselect features
Control+Left - cancel action/undo vertex
Right - confirm action
Dead (deleted) are internally only marked in the geometry file as 'dead' but it remains
there and occupies space. Any vector module used afterwards on this vector map which
really reads and writes vector geometry (so not g.copy) will writes only features which
are 'alive'.
Added or modified vector features are snapped to existing vector features
(Settings→General→Snapping). To disable snapping set the snapping threshold to
'0'.
If the digitizer crashes for some reason you can repair the vector map which was left open
with the v.build module.
REFERENCE
GRASS Vedit Library
SEE ALSO
wxGUI
wxGUI components
v.edit, v.category, v.build
See also the wiki page including video tutorials.
AUTHOR
Martin Landa, FBK-irst (2007-2008), Trento, Italy, and Czech Technical University in
Prague, Czech Republic
$Date: 2013-02-15 14:04:18 -0800 (Fri, 15 Feb 2013) $
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