[GRASSLIST:4845] Re: transition probability

[Markus Neteler]

On Mon, Nov 15, 2004 at 10:26:23AM -0800, Dylan Beaudette wrote:
> On Monday 15 November 2004 01:01 am, you wrote:
> > You have to join the tables in Postgres.
> > I hope to add join table to v.overlay later.
> >
> > Radim
> 
> Thanks for the tip Radim.
> 
> I was able to get the tables joined and re-attached to the vector layers by 
> using MySQL.
> 
> if anyone is interested, I have started documenting the process here;
> http://169.237.35.250/~dylan/grass_and_tp/
> 
> i have noticed that the attribute management section on the GRASS 57 tutorial 
> that -pertains to MySQL is empty. I would be willing to add to that section 
> if anyone is interested.

Yes, interested. 
In any case I want to work a bit on the tutorial the next day.
Contributions, comments are welcome.

Markus


> Thank again!
> 
> Dylan
> 
> > Dylan Beaudette wrote:
> > > On Saturday 13 November 2004 12:45 am, you wrote:
> > >>Dylan Beaudette wrote:
> > >>>If it hasn't, I am wondering if there are a couple of vector commands
> > >>>that could do the following:
> > >>>
> > >>>given an input polygon map of several categories, and a line drawn
> > >>> across these categories,
> > >>>
> > >>>1. sample the polygon boundaries(and their respective category) that the
> > >>>line intersects
> > >>>
> > >>>2. put the above information into a new vector line that contains line
> > >>>segments that have an attribute that matches the category of the polygon
> > >>>that they intersected.
> > >>
> > >>v.overlay
> > >>
> > >>Radim
> > >
> > > Seems that I just figured out the answer to my last question in regards
> > > to line vector types.
> > >
> > > However, I now have another perhaps more complicated problem..
> > >
> > > i have two maps:
> > >
> > > t_1 = line map containing a single line
> > >
> > > fresno_west = ploygon map with many polygons, and mulitple attributes per
> > > polygon:
> > > -------------------------
> > >  db.describe -c fresno_west
> > > Column 1: cat
> > > Column 2: AREA
> > > Column 3: PERIMETER
> > > Column 4: CA653_A_
> > > Column 5: CA653_A_ID
> > > Column 6: MUSYM
> > > Column 7: MUKEY
> > > ...
> > > ------------------------------
> > > when i use v.overlay with ainput=t_1 atype=line binput=fresno_west
> > > btype=area output=r_1 operator=and ...
> > > I get a map with the following attribute columns:
> > > ---------------------------
> > > db.describe -c r_1
> > > Column 1: cat
> > > Column 2: cata
> > > Column 3: catb
> > > ---------------------------
> > >
> > > this is almost what i want, as each of the line segments in the resulting
> > > map (r_1) is labeled with the category number corresponding to the
> > > polygon that it intersected in the catb attribute column:
> > > (http://basho.dept-lawr.ucdavis.edu/~dylan/temp/tp1.png)...
> > >
> > > this is great, but i need to join the attributes from the original
> > > polygon file to the new line file r_1. i imagine that it would be a join
> > > on: r_1.catb ---> fresno_west.cat
> > > ...which should then allow corresponding attributes from fresno_west (the
> > > polygon layer) to be connected to r_1 (the output from v.overlay)...
> > >
> > > i am able to connect the attribute table from fresno_west to r_1 with the
> > > command;
> > > v.db.connect map=r_1 table=fresno_west key=catb field=2 -o
> > >
> > > ...but this does not produce the results that i am looking for as the
> > > fresno_west table does not contain a 'catb' column...
> > >
> > > .... perhaps I am not fully comprehending the GRASS 57 vector attribute
> > > system.. any ideas?
> > >
> > > many thanks!

-- 
Markus Neteler     <neteler itc it>       http://mpa.itc.it
ITC-irst -  Centro per la Ricerca Scientifica e Tecnologica
MPBA - Predictive Models for Biol. & Environ. Data Analysis
Via Sommarive, 18        -       38050 Povo (Trento), Italy