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wxGUI Raster Digitizer


       display, GUI, raster, editing, digitizer


       Raster  Digitizer  is  a simple tool to quickly to draw lines, areas, and circles and save
       these features in a raster map.  It is accessible from Map Display toolbar (from the combo
       box on the right).

       Raster Digitizer currently allows you to:

           ·   draw polygons, lines and points

           ·   set category value of the feature you are drawing

           ·   set  feature  width  (width of currently digitized line or diameter of a digitized
               point in map units)

           ·   create a new raster from scratch or from an already existing raster

           ·   undo edits and save edits before leaving the digitizer

       The typical workflow includes these steps:

       1      Set computational region as needed.

       2      Switch to Raster Digitizer and select a map to create.  Select either a new  raster
              or  create a new raster from existing raster, also select raster type (CELL, FCELL,

       3      Specify category value and width before drawing a feature

       4      Specify digitizing tool (area, line, point)

       5      Start digitizing and when you want to finish area or line, use right click

       6      Change color of temporary overlay depending on your needs

       7      Set different category and repeat

       8      At any point you can use Undo or Save

       9      If existing raster is used for the new raster, digitized  areas  will  respect  the
              color table, but you can always set different color table.


       Raster Digitizer respects computational region including the currently set resolution.


       In  the following figures we start with elev_lid792_1m raster map in North carolina sample
       dataset and digitize two buildings, one rectangular and one with circular footprint.  Both
       buildings  have  the roof level at 130 m. We set the width when digitizing the point to 50
       meters which results in the building having 50 m in  diameter.   When  we  are  done  with
       digitizing,  we  save  the  result  and  explore  cast shadows of the buildings with r.sun
       g.region raster=elev_lid792_1m
       # now create elev_edited raster by digitizing and save
       r.slope.aspect elevation=elev_edited slope=elev_slope aspect=elev_aspect
       r.sun elevation=elev_edited aspect=elev_aspect slope=elev_slope beam_rad=beam day=172 time=6
       Figure: Steps to digitize new buildings on elev_lid792_1m raster map.


       wxGUI components, (backend of digitizer),


       Anna Petrasova, NCSU GeoForALL Laboratory


       Available at: wxGUI Raster Digitizer source code (history)

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