[postgis-users] RE: [mapserver-users] Shapefile Modification

[Juanse]

this is to big for me at this moment. You should rise your postgis questions
to postgis_users at postgis.refractions.net

probably you will have to subscribe.

The main dificulty is on finding that point where to cut the lines  at the
intersection (split). And most probably that point already do not exists (as
in your example) and will have to be drawn before intersecting.

Juanse

----- Original Message -----
From: Keith Baker <krbaker at metacarta.com>
To: Juanse <georef at tie.cl>
Sent: Monday, November 04, 2002 7:38 PM
Subject: RE: [mapserver-users] Shapefile Modification

Oh...  Good idea...

A few quick questions...
A) Good postgis docs?
B) Will this menthod solve sliced lines?

Imagine I had two polgyons A and B, touching along an edge.  I also have
a line which has a point in poly A and a point in poly B such that each
point is not touching the edges of A or B and the line is within the
polys.  If I want to remove the portion of the line in poly B I have to
calculate the intersection of the line with poly A, create a new point
and remove the old end in B...   Will postgis do this?

On Mon, 2002-11-04 at 17:03, Juanse wrote:
> I will go by using postSQL/GIS to do the necesary tables crossing (i am
not
> sure at this stage what you where trying to acomplich "SQL-intersect"?).
> Then dump that query as a newtable and go by ogr2ogr postgres to shape.
>
> Juanse
> temuko-chile
>
> ----- Original Message -----
> From: Lowther, David W <dlowther at ou.edu>
> To: 'Keith Baker' <krbaker at metacarta.com>; Drew from Zhrodague
> <drew at zhrodague.net>
> Cc: mapserver-users <mapserver-users at lists.gis.umn.edu>
> Sent: Monday, November 04, 2002 5:49 PM
> Subject: RE: [mapserver-users] Shapefile Modification
>
>
> > Keith,
> >
> > Have you checked out http://www.freegis.org/index.en.html? GRASS might
do
> > what you want or there may be another free / open product that would be
> > helpful.
> >
> > Option 2: How big is the shapefile? I might just do it for you in
Arcview
> if
> > its not too big...
> >
> > Dave
> >
> > -----Original Message-----
> > From: Keith Baker [mailto:krbaker at metacarta.com]
> > Sent: Monday, November 04, 2002 2:32 PM
> > To: Drew from Zhrodague
> > Cc: mapserver-users
> > Subject: Re: [mapserver-users] Shapefile Modification
> >
> >
> > Humm...  All suggestions turned out negitive.
> >
> > ogr2ogr can remove things based on extent, but not based on another
> > shapefile.  I may go hack away at it...  not sure yet.  Seems like
> > something someone must have done.  I don't want to have to purchase
> > ArcView for this project if I can avoid it.

>




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