labels<-->category# ???

Malcolm Williamson malcolm at
Thu Jun 17 09:37:50 EDT 1993

> We have obtained 7.5 min vector soil maps where the labels are
> meaningful but the category numbers vary as a function of the
> quad map.  Thus gives meaningless category numbers
> with meaningful labels.  How do I combine these maps into one
> complete soil map for the county? V.patch and r.mapcalc work on
> the category number and more or less ignore the labels. Is there
> a slick way to make the labels the category # in either vector
> or raster formats?
> Bruce Wylie
The easiest way that I can think of is to use r.mapcalc with the "@" operator,
which looks at the category contents instead of the category value. For example:

>newmap = @oldmap

The GRASS4.1 manual notes that "...the category label must start with a valid 
number. Missing labels, or labels that do not start with a number will 
(silently) produce a 0 value for that category."

Malcolm D. Williamson - Research Assistant       E-mail: malcolm at
Center for Advanced Spatial Technologies      Telephone: (501) 575-6159
Ozark Rm. 12                                        Fax: (501) 575-3846 
University of Arkansas              
Fayetteville, AR 72701

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