[GRASS-user] derive points outlet from r.stream.extract
Giuseppe Amatulli
giuseppe.amatulli at gmail.com
Wed Apr 29 17:11:18 PDT 2020
Thanks Huidae (& Markus),
I was writing to the list when I get your message.
In the end, I discover that the outlet are visible by v.category
v.category input=stream layer=2 type=point option=print
and I was able to directly convert to raster by
v.to.rast input=stream type=point use=cat label_column=type_code
output=outlet cats=2
Probably is good to insert in the manual that the layer=2 is visible with
v.category.
Thanks again
Giuseppe
p.s. I will write another message concerning some border effect in
r.stream.basins
On Wed, 29 Apr 2020 at 19:19, Huidae Cho <grass4u at gmail.com> wrote:
> Giuseppe,
>
> r.stream.extract does not link a table to layer 2, but layer 2 is there.
> You can display outlets in GUI. Select layer=2 and cat=2 in d.vect.
> [image: image.png]
>
> Now, you want to extract the outlets.
>
> v.extract input=extract_output layer=2 cat=2 output=outlets1
>
> The outlets are still in layer 2 in the outlets1 map and they all have the
> same cat (2).
> v.category map=outlets1 option=report
>
> Change the layer from 2 to 1.
> v.category input=outlets1 layer=2,1 option=chlayer output=outlets2
>
> Delete all cats (2) because they're just the same.(useless).
> v.category input=outlets2 option=del cat=-1 output=outlets3
>
> Add unique cats.
> v.category input=outlets3 option=add output=final_outlets
>
> Let's see.
> v.report map=final_outlets option=coor
>
> How do you link these points in final_outlets back to the original
> extract_output? Now, you need to add a table to final_outlets.
> v.db.addtable map=final_outlets column='src_cat int'
>
> v.what.vect map=final_outlets col=src_cat query_map=extract_output
> query_column=cat
>
> Check
> v.report map=final_outlets option=coor
>
> Hope this helps.
>
> Best,
> Huidae
>
>
> On Mon, Apr 27, 2020 at 6:25 AM Markus Neteler <neteler at osgeo.org> wrote:
>
>> Hi Giuseppe,
>>
>> Could you post a reproducible example with North Carolina samle data?
>> (being tight on time it would help)
>>
>> Best
>> Markus
>>
>> On Thu, Apr 23, 2020 at 8:53 PM Giuseppe Amatulli
>> <giuseppe.amatulli at gmail.com> wrote:
>> >
>> > 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/
>> > _______________________________________________
>> > grass-user mailing list
>> > grass-user at lists.osgeo.org
>> > https://lists.osgeo.org/mailman/listinfo/grass-user
>>
>>
>>
>> --
>> Markus Neteler, PhD
>> https://www.mundialis.de - free data with free software
>> https://grass.osgeo.org
>> https://courses.neteler.org/blog
>> _______________________________________________
>> grass-user mailing list
>> grass-user at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/grass-user
>
>
>
> --
> Huidae Cho, Ph.D., GISP
> GRASS GIS Developer
> https://idea.isnew.info
>
--
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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