1wxGUI.rdigit(1) GRASS GIS User's Manual wxGUI.rdigit(1)
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7 display, GUI, raster, editing, digitizer
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10 Raster Digitizer is a simple tool to quickly draw lines, areas, and
11 circles and save these features in a raster map. It is accessible from
12 the Map Display toolbar (from the combo box on the right).
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14 Raster Digitizer currently allows you to:
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16 • draw polygons, lines and points
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18 • set category value of the feature you are drawing
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20 • set feature width (width of currently digitized line or diame‐
21 ter of a digitized point in map units)
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23 • create a new raster from scratch or from an already existing
24 raster
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26 • undo edits and save edits before leaving the digitizer
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28 The typical workflow includes these steps:
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30 1 Set computational region as needed.
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32 2 Switch to Raster Digitizer and select a map to create. Select
33 either a new raster or create a new raster from existing raster,
34 also select raster type (CELL, FCELL, DCELL)
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36 3 Specify category value and width before drawing a feature
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38 4 Specify digitizing tool (area, line, point)
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40 5 Start digitizing and when you want to finish area or line, use
41 right click
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43 6 Change color of temporary overlay depending on your needs
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45 7 Set different category and repeat
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47 8 At any point you can use Undo or Save
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49 9 If existing raster is used for the new raster, digitized areas
50 will respect the color table, but you can always set different
51 color table.
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54 Raster Digitizer respects computational region including the currently
55 set resolution.
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58 In the following figures we start with elev_lid792_1m raster map in
59 North carolina sample dataset and digitize two buildings, one rectangu‐
60 lar and one with circular footprint. Both buildings have the roof
61 level at 130 m. We set the width when digitizing the point to 50 meters
62 which results in the building having 50 m in diameter. When we are
63 done with digitizing, we save the result and explore cast shadows of
64 the buildings with r.sun module:
65 g.region raster=elev_lid792_1m
66 # now create elev_edited raster by digitizing and save
67 r.slope.aspect elevation=elev_edited slope=elev_slope aspect=elev_aspect
68 r.sun elevation=elev_edited aspect=elev_aspect slope=elev_slope beam_rad=beam day=172 time=6
69 Figure: Steps to digitize new buildings on elev_lid792_1m raster map.
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72 wxGUI
73 wxGUI components,
74 r.in.poly (backend of digitizer),
75 g.gui.vdigit
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78 Anna Petrasova, NCSU GeoForALL Laboratory
79 Tomas Zigo (standalone module)
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82 Available at: wxGUI Raster Digitizer source code (history)
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84 Accessed: Saturday Jan 21 21:17:59 2023
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86 Main index | GUI index | Topics index | Keywords index | Graphical in‐
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89 © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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93GRASS 8.2.1 wxGUI.rdigit(1)