[GRASS-user] derive points outlet from r.stream.extract

Giuseppe Amatulli giuseppe.amatulli at gmail.com
Thu Apr 23 11:53:40 PDT 2020


Hi,
I'm trying to extract the outlet location from the
r.stream.extract stream_vector=stream  attribute.
In particular the manual for r.stream.extract reports:

"In layer 2, categories are identical to type_code in layer 1 with
additional category 2 = outlet for outlet points."

I want to be able to extract only the points of layer 2 where category = 2.
However when I run

v.db.connect  -p   map=stream
Vector map <stream> is connected by:
layer <1/stream> table <stream> in database
</tmp/grass7-ga254-12721/tmploc/PERMANENT/sqlite/sqlite.db> through driver
<sqlite> with key <cat>

I can see only layer 1 (which does not contain category 2).

Is there a way to connect to layer 2?
How I can be sure that also layer 2 has been created and is not missing?
Thanks
Giuseppe

GRASS 7.6.0 (tmploc):/gpfs/scratch60/fas/sbsc/ga254/dataproces/MERIT_HYDRO
> v.info   map=stream
 +----------------------------------------------------------------------------+
 | Name:            stream
   |
 | Mapset:          PERMANENT
  |
 | Location:        tmploc
   |
 | Database:        /tmp/grass7-ga254-25033
  |
 | Title:
  |
 | Map scale:       1:1
  |
 | Name of creator: ga254
  |
 | Organization:
   |
 | Source date:     Thu Apr 23 14:42:51 2020
   |
 | Timestamp (first layer): none
   |
 |----------------------------------------------------------------------------|
 | Map format:      native
   |
 |----------------------------------------------------------------------------|
 |   Type of map: vector (level: 2)
  |
 |
   |
 |   Number of points:       250905          Number of centroids:  0
   |
 |   Number of lines:        245570          Number of boundaries: 0
   |
 |   Number of areas:        0               Number of islands:    0
   |
 |
   |
 |   Map is 3D:              No
  |
 |   Number of dblinks:      1
   |
 |
   |
 |   Projection: Latitude-Longitude
  |
 |
   |
 |               N:       77:06:40.5N    S:       73:10:55.5N
  |
 |               E:      158:07:46.5E    W:      135:26:34.5E
  |
 |
   |
 |   Digitization threshold: 0
   |
 |   Comment:
  |
 |
   |
 +----------------------------------------------------------------------------+



-- 
Giuseppe Amatulli, Ph.D.

Research scientist at
School of Forestry & Environmental Studies
Center for Research Computing
Yale University
New Haven, CT, USA
06511
Teaching: http://spatial-ecology.net
Work:  https://environment.yale.edu/profile/giuseppe-amatulli/
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