[postgis-users] Extracting the Linestring Geometry from a BBox(noob)

[Pedro Doria Meunier]

Hey Andrew,

 

I had to do a similiar thing


“Cut” the road segments belonging to a municipality
 and the query ended
like this:

 

create my_road_segment as

select intersection(r.geometry, f.geometry) as geometry,

r.name, r.sec_name, r.city, r.region, r.country, r.pcode, r.road_type,

r.route_class, r.speed_class, r.one_way, r.has_dir, r.toll, r.no_car,

r.no_bus, r.no_taxi, r.no_bic, r.no_truck, r.no_emerg, r.no_deliv,
r.no_pedes, r.classific

from rede_estradas as r, freguesias_ram as f

where r.geometry && f.geometry

and intersects(r.geometry, f.geometry)

and f.nome_freg like 'Fajã da Ovelha%';

 

the keyword here is INTERSECTS

 

This query creates a table based on a select. This select returns the road
segments *contained* in a polygon defining a municipality.

 

Hope this helps.

 

Pedro Doria Meunier

(351) 91 302 49 72 - (351) 96 247 99 12

MSN - pdoriam at hotmail.com

ICQ - 308-182-126

Skype: pdoriam

 

  _____  

From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Andrew
Hughes
Sent: segunda-feira, 27 de Novembro de 2006 7:22
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] Extracting the Linestring Geometry from a
BBox(noob)

 

Hey All,

I'm trying to extract some linestrings from a collection of linestrings  and
conditional on being within a BBox.

I will try and explain this best with some images...

My input looks like:



My desired output looks like this:

(note that I DO want the point where it intersects the bbox)



Is this at all possible to do? or do I need to start writing my own postgis
fuctions???



Thanks  in advance

--AH

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