Digitizing in GRASS Part II

[Alejandro Imass]

Hello to All.

We found that trim does the job asked for in the previous mail, but the
question still remains: is there a manual way to do it in the digitizer?

Now I have a bigger problem:

If I digitize 3 polygons , one which is contained in the other two
(intersects the bigger ones), I am obligated to have at least 4 nodes,
where
the polylines join (X mark the nodes):


***************************************
*
*
*
*
*                               POLYGON 1
*
*                                  ******************              *
*
*                                      *            *
X**************X      POLYGON 3      X*****X
*
*                                       *            *
*                                  ******************               *
*
*
*                            POLYGON
2                                       *
*
*
*****************************************

When I export the above file into GRASS native ASCII format or to
ARC/INFO ASCII format I get 6 polygons because the system closes the
polylines at the nodes (it adds new lines between the nodes cutting the
whole thing in may other polygons.

If the areas are being labeled correctly and they are only three, how
come the system has to close these polygons again when exporting.

Any clues?

Thank You,
Alejandro Imass