[GRASS-user] Not matching categories/line IDs
johannesradinger at gmail.com
Thu Sep 13 23:53:12 PDT 2018
I created a zipped version of a test location including one PERMANENT
mapset that includes the vector map that causes these inconsistencies
(Ebro_river_vector_poly_clean_tmp). The test location can be downloaded
from here: https://we.tl/t-eSUZqfP0TQ. I also included the initial vector
map before running the v.clean tool (Ebro_river_vector_poly_tmp). More
specifically, I am using following code:
Maybe this helps to find out what happens here.
On Thu, Sep 13, 2018 at 10:26 PM Markus Metz <markus.metz.giswork at gmail.com>
> On Thu, Sep 13, 2018 at 10:50 AM Johannes Radinger <
> johannesradinger at gmail.com> wrote:
> > Hi all,
> > I am a little bit puzzled about the actual number of lines/categories of
> a specific vector map (river network). As discussed yesterday, the output
> of v.category with the report option provides a column 'count' which is a
> feature count. Running v.category option=report on my vector provides me
> > v.category input=Ebro_river_vector_poly_clean_tmp at Ebro2_alien_spread
> > Layer/table: 1/Ebro_river_vector_poly_clean_tmp
> > type count min max
> > point 0 0 0
> > line 804 1 1053
> > ....
> > This would indicate that I have 804 line features. However, using the
> tool v.info on the same vector I get following different result regarding
> the number of lines:
> > v.info map=Ebro_river_vector_poly_clean_tmp at Ebro2_alien_spread
> > | Name: Ebro_river_vector_poly_clean_tmp
> > ...
> > | Number of points: 0 Number of centroids: 0
> > | Number of lines: 799 Number of boundaries: 0
> > ...
> > And even more puzzling, I then added a table to this vector map and the
> output of v.db.addtable is:
> > v.db.addtable map=Ebro_river_vector_poly_clean_tmp at Ebro2_alien_spread
> > Reading features...
> > Updating database...
> > 803 categories read from vector map (layer 1)
> > 803 categories read from vector map don't exist in selection from table
> > 803 records updated/inserted (layer 1)
> If there are 804 features, 2 features must have the same category value,
> resulting in 803 updates to the database
> > So, is it 804,799 or 803??
> The output of v.info and v.category option=report must be identical with
> regard to the count of features.
> > The map I am using is a polyline river network (cat=first) that has gone
> trough the tool v.clean with the options:
> break,rmdupl,rmline,rmsa,rmdangle. The number of lines and cats before the
> cleaning tool is 805 (consistent output among all tools).
> > So I am wondering what happens during cleaning and how to get a clean
> map with a corresponding table that has entries for each cat, and were each
> cat represents one line feature (i.e. that the number of cats/line features
> is consistent over the multiple tools).
> > Please let me know if I should share the vector map (and how, which
> Ideal would be a stripped down GRASS mapset with only this vector
> Ebro_river_vector_poly_clean_tmp. Exporting the vector would change the
> geometry representation and it would no longer be possible to reproduce the
> Markus M
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