label errors v.in.arc

[Jill Schuler]

%%%   I've managed to convert a number of coverages from arc7 to grass.  It's
%%%work great except that a large number of polygons on each cover don't
%%%get labeled.  It get lots of point to area errors.  Has anyone run into
%%%this problem and been able to fix it?  I dread the thought of having to
%%%fix this by hand... it's several thousand polygons over several coverages.
%%%

Kurt,  
In the past I have seen this when importing dlg's.  I will assume that the
problem is simular.

The problem maybe that the map threshold is not set correctly in the import 
routine in GRASS.  The import routine uses the scale to determine the 
digitizing threshold and the snapping threshold. 

WORK AROUND *************************************
If you go into v.digit and reset the map scale (I know this really is not 
what you want to do) to a smaller value, then the map threshold will also 
be smaller.  

Write out the session and exit v.digit.  Then run the file through v.support.  
You should see a difference in the number of label errors. 
Keep adjusting the map scale until you have resolved all the label
errors.

In 4.0 GRASS you could change your digitizing threshold and snap threshold
then exit v.digit.  For some reason?? 4.1 GRASS will not let you do this.
When you exit, even after writing out a session, and re-enter v.digit the 
default values are back.

Cheers,
Jill

*********************************************************************

#  # #### #### ####      ######  #### ##### Jill R. Schuler
#  # #    #  # #  #      #      #     #     USDA 
#  # #### #  # #### ### ####   #     ####   Soil Conservation Service
#  #    # #  # #  #        #  #         #   National Cartography and 
#  #    # #  # #  #       #  #         #    GIS Center
#### #### #### #  #   ####  ###### ####     P.O. Box 6567 
				            Ft. Worth, TX 76115
e-mail: jschuler at ncg.scs.ag.gov             Phone: (817) 334-5559 x3086

*********************************************************************