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Umwandlung von Vektor- in Rasterdaten

Um die Vektorlinie in eine Rasterdatei umzuwandeln, verwendet man `v.to.rast`, nachdem man mit `v.support mask` die von GRASS benötigten weiteren Dateien erzeugt. Die Frage nach den im Speicher zu haltenen Zeilen kann mit 512 bestätigt werden.

    GRASS:~GRASS:/spare/gisdata/grass/bin > v.support mask

       V.SUPPORT:

    Selected information from vector header
     Organization:
     Map Name:
     Source Date:
     Orig. Scale:   0
     No snapping will be done

        Reading Vector file.
     100%
        Building areas
        Building islands
        Attaching labels
     Number of lines:   1
     Number of nodes:   1
     Number of areas:   1
     Number of isles:   1
     Number of atts :   0
     Number of unattached atts :   0
     Snapped lines  :   0

    GRASS:/spare/gisdata/grass/bin > v.to.rast
    OPTION:   vector input file
    key: input
    required: YES

    Enter the name of an existing vector file
    Enter 'list' for a list of existing vector files
    Hit RETURN to cancel request
    > mask

    Enter a new raster file name
    Enter 'list' for a list of existing raster files
    Hit RETURN to cancel request
    > mask

    Parameters:
    input   vector input file
    output   raster output file
    rows   number of rows to hold in memory
    default: 512
    required: NO
    enter option >
    Loading vector information ...                  0 mins 00 secs
    Sorting areas by size ... 1 areas               0 mins 00 secs
    Pass #1 (of 2)
      Processing areas ... 1 areas                  0 mins 00 secs
      Processing lines ... 0 lines                  0 mins 00 secs
      Processing sites ... 0 sites                  0 mins 00 secs
      Writing raster map ...                        0 mins 00 secs
    Pass #2 (of 2)
      Processing areas ... 1 areas                  0 mins 00 secs
      Writing raster map ...                        0 mins 00 secs
    Creating support files for raster map ...       0 mins 01 sec

    Raster map <mask> done.
    Total processing time:    0 mins 01 sec

Die Maske selbst wird mit dem Befehl `r.mask` gesetzt, der alternativ auch Masken entfernt. Die erfolgte Maskierung erzeugt eine Rasterdatei MASK die mit `d.rast -o map=MASK` angezeigt werden kann.

    GRASS:/spare/gisdata/grass/bin > r.mask mask

    MASK:  Program for managing current GIS mask

    current mask:          none

    Options:
        1      Remove the current mask
        2      Identify a new mask
      RETURN   Exit program

    >2

    Enter name of data layer to be used for mask
    Enter 'list' for a list of existing raster files
    Enter 'list -f' for a list with titles
    Hit RETURN to cancel request
    >mask

    IDENTIFY THOSE CATEGORIES TO BE INCLUDED IN THE MASK

    OLD CATEGORY NAME                                          CAT
                                                               NUM

    . . . . . . . . . . . . . . . . . . . . . . . . . .   0     0_
    . . . . . . . . . . . . . . . . . . . . . . . . . .   1     1_

         Next category: end__  (0 thru 1)

    AFTER COMPLETING ALL ANSWERS, HIT <ESC><ENTER> TO CONTINUE
                      (OR <Ctrl-C> TO CANCEL)