snapping areas in v.digit

[Rainer Trusch]

Am Wed, 20 Jan 1999 schriebst Du:
>Hi all,
>
>I try to digitize a soil map with v.digit. The areas, which lay side by side are
>using the same line as a common border.
>How do I manage to digitize these areas without digitizing each line a second
>time for the adjacent areas? Can I snap one area with with another open area to
>get two closed polygons?
>
>Thanks in advance
>
>	Juergen Rogozia


Hi Juergen,

I did some digitizing with v.digit, but only with a mouse (don´t know what you
are using, but it shouldn´t make a big difference, in case you are using a
digitizer). Basically, you have to set a node at all the points, where lines
of the two polygons join to a single one. Just quit digitizing the line
at this point and start the new ones at it (this takes always four mouseclicks,
but you get used to it). If you want to join a line you are currently
digitizing, let it end on the node. Before you start digitizing, adjust a decent
snapping threshold (Customize Menu), that the lines are joining properly. 

If you forgot to set a node, use ´break a line´ in the Edit Menu. In case a
line didn´t join properly with a node, correct it afterwards with ´Snap Line to
Node´ in the same menu. It might help to solve your second problem as well.

Using v.digit, you have to become a sort of keyboard DJ (never understood the
idea of using capital letters to open the menus), but after a while it´s okay
and you can digitize pretty fast. A copy of the ´GRASS 4.0 Map Digitizing
Manual: v.digit´ would be handy, if you don´t have it at all. you can get it
from:   http://www.geog.uni-hannover.de/grass/
It´s part of the documentation package and perhaps you get it seperatly as well.



Best wishes

Rainer