[GRASS-user] Relationships of Raster & Vector Attribute Data

[Rich Shepard]

On Thu, 3 May 2012, Markus Neteler wrote:

> It is in the cats/ subdirectory.

Markus,

   Interesting:

# 166 categories
Watershed basins

0.00 0.00 0.00 0.00
dem.basin lines 1-4/4 (END)

> They are created if the raster maps has category labels (see
> r.category).

   dem.basin: even numbers 2-166.

> GRASS 6.4.3svn (nc_spm_08):~ > v.db.select myzipcodes

v.db.select basinv
cat|value|label
2|126|
3|126|
4|110|
5|2|
6|2|
7|96|
8|122|
9|20|
10|98|
11|126|
12|60|
13|130|
14|4|
15|58|
16|108|
17|14|
18|120|
19|124|
20|120|

> Maybe too late here, I don't get the last question.

   Notice above from basinv: cats 2 and 3 have same value (but r.category
shows only even number cats for the raster version, dem.basin). Also cats 18
and 20 have the same value. That's what I mean by my third question: why
more categories in the vector produced in r.to.vect than in the raster
source, and why duplicate values for different categories?

Rich

> Markus
>

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Richard B. Shepard, Ph.D.          |   Integrity - Credibility - Innovation
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