                                                                erase_seg 
Chapter 9 Input Modes

erase_seg

    Changes input mode to erase raster segment closest to input position.
     
         erase_seg

    Changes input mode to erase the raster segment closest to location
    specified by the start or continue commands.   When in this mode, start or
    continue causes the file to be searched for the closest raster pixel to the
    input position (limited by the user-defined search radius in the header
    file).  The raster is then erased from that pixel in both directions until
    a raster junciton or spur endpoint is reached.  NOTE: To repair changes
    made with erase_seg, reference disprstr_get, recall and undo commands.

    THE DIFFERENCES BETWEEN erase_obj AND erase_seg ARE:

         1)   erase_obj requires assembly while erase_seg does not.
         2)   erase_obj will only erase a node/segment/polygon if it matches a
              vector object.  erase_seg doesn't look for a match and will
              continue  to the  first, current junction.
         3)   erase_obj will stop erasing a segment or polygon when the
              position of a vector node is reached, even when the node is no
              longer a junction or endpoint on the raster.  erase_seg will
              erase any raster data back to the first raster junction in both
              directions, no matter what.
         4)   erase_obj checks for an endpoint and length match between the
              raster and vector objects before erasing.  erase_seg does no
              checking.
    ___________________________________________________________________________
    Options/arguments:

    None.
    ___________________________________________________________________________
    Example(s):

    To erase the segment closest to the position defined by x=450 and y=678,
    enter:
     
         erase_seg
         continue 450 678
    ___________________________________________________________________________
    See also:

              del_objects, disprstr_get, erase_obj, erase_seg, header,
              recall, save, undo
    ___________________________________________________________________________
