[GRASSLIST:234] Re: [GRASS5] Built-in vector documentation extended
Michael Barton
michael.barton at asu.edu
Fri Mar 17 17:27:23 EST 2006
Thomas,
You must have an integer key field. I looked in the v.in.db
documentation--generally a good idea. It says that for Postgres you can use
the object id in the following way.
2) Creating a map from PostGIS:
To extract coordinate values from PostGIS, functions have to be used:
v.in.db driver=pg database="host=myserver.itc.it,dbname=mydb,user=name" \
table=station x="x(geom)" y="y(geom)" z="z(geom)" key=id
out=meteostations
If an ID column is not not present in the PostgreSQL table, the 'object ID'
of PostgreSQL can be used. In this case set:
cat=OID
Otherwise you must create a key field. The key=# argument is for you to
specify which field in your data table will serve as the key field. You are
putting in an integer VALUE rather than the name of a column in your table.
Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402
phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton
> From: Thomas Adams <Thomas.Adams at noaa.gov>
> Date: Fri, 17 Mar 2006 14:55:52 -0500
> To: Michael Barton <michael.barton at asu.edu>
> Cc: Markus Neteler <neteler at itc.it>, Multiple recipients of list
> <grasslist at baylor.edu>
> Subject: Re: [GRASS5] Built-in vector documentation extended
>
> Michael,
>
> Your instructions did not help... I'm sorry to be a bother about this,
> so, I'll restate the problem I'm having.
>
> I have a Postgres database with a table called 'location', which
> consists of meteorological observation points with lat-long coordinates
> along with various other attributes:
>
> CHARACTER|lid
> CHARACTER|county
> CHARACTER|coe
> CHARACTER|cpm
> CHARACTER|detail
> DOUBLE PRECISION|elev
> CHARACTER|hdatum
> CHARACTER|hsa
> CHARACTER|hu
> DOUBLE PRECISION|lat
> DOUBLE PRECISION|lon
> CHARACTER|lremark
> DATE|lrevise
> CHARACTER|name
> CHARACTER|network
> CHARACTER|rb
> CHARACTER|rfc
> DATE|sbd
> CHARACTER|sn
> CHARACTER|state
> CHARACTER|waro
> CHARACTER|wfo
> CHARACTER|wsfo
> CHARACTER|type
> CHARACTER|des
> CHARACTER|det
> INTEGER|post
> CHARACTER|stntype
> CHARACTER|tzone
>
> Please notice that only one field is type integer, namely, the 'post'
> field; it is a boolean (1 or 0).
>
> When I use the GRASS v.in.db command:
>
> v.in.db driver=pg database=host=dell3-tir,dbname=hd_ob6tir
> table=location x=-1*lon y=lat z=elev key=1 where=rfc='OHRFC'
> output=locations
>
> I am forced to supply key=???; the only thing that works for me is key=0
> or key=1, etc. since I have no integer field with unique integer values.
> If I run v.in.db (above), I get:
>
> GRASS_INFO_MESSAGE(19616,1): 5030 points written to vector
> Building topology ...egistering lines: 1000 2000 3000 4000 5000
> 5030 primitives registered
> Building areas:
>
>
> 0 areas built
> 0 isles built
> Attaching islands:
> Attaching centroids:
> Topology was built.
> Number of nodes : 4729
> Number of primitives: 5030
> Number of points : 5030
> Number of lines : 0
> Number of boundaries: 0
> Number of centroids : 0
> Number of areas : 0
> Number of isles : 0
>
>
> GRASS_INFO_MESSAGE(19616,2): Vector import complete
>
> Which, I guess, looks OK. If I then use v.category:
>
> v.category input=locations output=locations_new
> type=point,line,boundary,centroid,area option=add cat=1 layer=1 step=1
> DBMI-Postgres driver error:
> Cannot create index:
> create unique index locations_new_1 on locations_new ( 1 )
> ERROR: syntax error at or near "1" at character 56
>
>
>
> GRASS_INFO_WARNING(19064,1): Cannot create index
> 0 new centroids placed in output map
> Building topology ...egistering lines: 1000 2000 3000 4000 5000
> 5030 primitives registered
> Building areas:
>
>
> 0 areas built
> 0 isles built
> Attaching islands:
> Attaching centroids:
> Topology was built.
>
> Number of nodes : 4729
> Number of primitives: 5030
> Number of points : 5030
> Number of lines : 0
> Number of boundaries: 0
> Number of centroids : 0
> Number of areas : 0
> Number of isles : 0
>
> Which has errors, and does nothing for solving my problem. If I use the
> GRASS query tool for the 'locations' or my newly created 'locations_new'
> vector maps, the x,y,z data is correct from v.in.db, but all the
> category data is the same, namely, for the first record of my Postgres
> table.
>
> Consequently, trying to re-project the points into a LCC location using
> v.proj fails. Not to mention the fact that all the attribute data for my
> points in my lat-long location is useless because it's all the same.
>
> How do I deal with this? Your help is appreciated.
>
> Regards,
> Tom
>
>
> Michael Barton wrote:
>> Thomas,
>>
>> See below.
>>
>> Michael
>> __________________________________________
>> Michael Barton, Professor of Anthropology
>> School of Human Evolution and Social Change
>> Arizona State University
>> Tempe, AZ 85287-2402
>>
>> phone: 480-965-6213
>> fax: 480-965-7671
>> www: http://www.public.asu.edu/~cmbarton
>>
>>
>>
>>
>>> From: Thomas Adams <Thomas.Adams at noaa.gov>
>>> Date: Fri, 17 Mar 2006 12:37:20 -0500
>>> To: Michael Barton <michael.barton at asu.edu>
>>> Cc: Markus Neteler <neteler at itc.it>, grass developers list
>>> <grass5 at grass.itc.it>, Multiple recipients of list <grasslist at baylor.edu>
>>> Subject: Re: [GRASS5] Built-in vector documentation extended
>>>
>>> Michael,
>>>
>>> This is very helpful and answers many questions I have about the new
>>> vector format, especially points. I do want to confirm my understanding
>>> from "Vector data processing in GRASS GIS" (please pardon my being
>>> obtuse). SoŠ
>>>
>>> In order to get a Postgres table consisting of point coordinates and
>>> various attributes to import into my lat-long location using v.in.db, I
>>> had to put a "1" in the field for the "category column name (string
>>> required)"; when I put "lid" in the field, I got an error saying the
>>> type was not an integer. It seems GRASS is expecting a string for the
>>> field name that has integer as its type. My problem is that none of my
>>> fields meet this requirement for the key field, the only column that
>>> does, "lid", has type string.
>>>
>>
>> The GRASS vector key field ("category") MUST be an integer. The matching key
>> field in your attribute table must also be integer to make a join.
>>
>>
>>> Now, my question is, for 5030 records, how do I add an integer key
>>> field? My guess is that I would have to write a script that (1) created
>>> a new column (type integer) for the Postgres table and (2) looped,
>>> sequentially filling the new field for each record with a unique integer
>>> value ‹ or I could drop the table, and do all of this outside of the
>>> Postgres/GRASS environment and reload the table. The problem I have with
>>> doing either is that the table design is not my own and is controlled by
>>> 'outsiders'.
>>>
>>
>> Use v.category to do this in GRASS.
>>
>> Michael
>>
>>
>>> Regards,
>>> Tom
>>>
>>> Michael Barton wrote:
>>>
>>>> Markus,
>>>>
>>>> This is very helpful. It will make learning GRASS vector architecture much
>>>> easier for people.
>>>>
>>>> Michael
>>>> __________________________________________
>>>> Michael Barton, Professor of Anthropology
>>>> School of Human Evolution and Social Change
>>>> Arizona State University
>>>> Tempe, AZ 85287-2402
>>>>
>>>> phone: 480-965-6213
>>>> fax: 480-965-7671
>>>> www: http://www.public.asu.edu/~cmbarton
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>> From: Markus Neteler <neteler at itc.it>
>>>>> Date: Thu, 16 Mar 2006 22:35:22 +0100
>>>>> To: grass developers list <grass5 at grass.itc.it>
>>>>> Cc: GRASS user list <grasslist at baylor.edu>
>>>>> Subject: [GRASS5] Built-in vector documentation extended
>>>>>
>>>>> Hi,
>>>>>
>>>>> I have extended the vector overview document in
>>>>> 6.1-CVS, find also here:
>>>>>
>>>>> http://grass.itc.it/grass61/manuals/html61_user/vectorintro.html
>>>>>
>>>>> While it covers most modules, each now in a thematic
>>>>> context, it may be fine tuned, improved.
>>>>> Text pieces welcome (preferably CVS patches).
>>>>>
>>>>> The idea is to give a short overview.
>>>>>
>>>>> Currently the page is even W3 conformant :-)
>>>>>
>>>>> Cheers
>>>>>
>>>>> Markus
>>>>>
>>>>>
>>>>>
>>>> _______________________________________________
>>>> grass5 mailing list
>>>> grass5 at grass.itc.it
>>>> http://grass.itc.it/mailman/listinfo/grass5
>>>>
>>>>
>>>>
>>> --
>>> Thomas E Adams
>>> National Weather Service
>>> Ohio River Forecast Center
>>> 1901 South State Route 134
>>> Wilmington, OH 45177
>>>
>>> EMAIL: thomas.adams at noaa.gov
>>>
>>> VOICE: 937-383-0528
>>> FAX: 937-383-0033
>>>
>>>
>>
>>
>>
>
>
> --
> Thomas E Adams
> National Weather Service
> Ohio River Forecast Center
> 1901 South State Route 134
> Wilmington, OH 45177
>
> EMAIL: thomas.adams at noaa.gov
>
> VOICE: 937-383-0528
> FAX: 937-383-0033
>
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