I think that all of the chatter on the list about alternative
technologies comes from the latter part of Andrew's post -- asking about
query mechanisms. GeoServer allows you to get the data back out as a
rendered map (WMS) or as raw GML (WFS). Both allow you to reproject on
the fly. But for the querying (point in polygon, etc.), GeoServer is
probably not going to help you out. It's GeoInfrastructure/Distribution,
not GeoAnalysis.
Well, if he's just looking to query single points against a set of 30
different shapefiles then you can utilize a Filter - which is basically
a WHERE statement, that can also handle spatial queries. GeoServer
supports all spatial filters possible in WFS, which is basically the set
defined in the Simple Features for SQL specification that PostGIS is
based on (and if PostGIS is there we pass it straight to it for
processing, otherwise we use JTS when the backend can't handle it).
The big limitation with WFS is that it doesn't let you do any kind of
'join', so if you have a huge set of points you can't just pass them all
in. Though you could get slightly around that passing in a multi-point.
But you always have to pass it in, you can't refer to other tables on
the server.
Note that WFS 1.0 doesn't let you reproject on the fly, but WFS 1.1
does, and we're just now finishing up reference implementation work for
OGC, so that should be in the GeoServer mainstream within a couple of
months.
If you're looking to do this through web services and to pass in points
each time than GeoServer might work out for you, just use a Within
filter. But if you're just running algorithms on a local machine than
using GeoServer is definitely overkill - it's built on top of GeoTools
and JTS, and PostGIS is its more popular backend, so you'd likely be
better off using one of those directly.
best regards,
Chris
If you slurp the shapefiles into PostGIS (shp2pgsql makes it trivial),
then you can do the queries you are looking for. You can also write code
to do it in JTS and GeoTools, but PostGIS' queries might offer the path
of least resistance for you. PostGIS allows you to reproject on the fly
as well. PostGIS has some pretty nice documentation that should help --
http://postgis.refractions.net/documentation/ . They also have a very
active mailing list.
HTH,
s
P.S. Best. Elephant. Analogy. Ever.
Scott Davis
[EMAIL PROTECTED]
Original Post:
On 1/16/07, [EMAIL PROTECTED] <[EMAIL PROTECTED] > wrote:
Hi all,
I'm working on an algorithm that will test whether a point falls into
various polygons defined by ~30 different shape files with various
projections. I've started digging into GeoServer, which seems to have no
problems loading the majority of the shapefiles. In your experience is
GeoServer a good fit for this kind of query? Also, what is your favorite
query mechanism (something that supports reprojection would be nice since
I'm pulling a lat/long off of a google map and testing it against several
different projections)
Thanks for your input!
-= Andrew Fortier
On Jan 17, 2007, at 9:10 AM, steven citron-pousty wrote:
Let's see - by using the logic of this list so far I would say the
response to Paul's elephant questions is:
An elephant seems a but heavyweight for an animal, let me tell you
about this great goldfish I have.
Sheesh -
the original post asked the person about geoserver and people's
experience with it. I was stoked and wanted to hear more about that.
Instead all I got was a whole bunch of people suggesting other
goespatial libraries without any real understanding of why the person
was asking.
Between Steve Jobs and the geowanking list I am getting pretty peeved
about the whole anti-java sentiment. Enough already
</soapbox>
Steve
------------------------------
Message: 7
Date: Tue, 16 Jan 2007 21:46:17 -0800
From: Paul Ramsey <[EMAIL PROTECTED]>
Subject: Re: [Geowanking] Re: Opinions about GeoServer
To: [email protected]
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=US-ASCII; format=flowed
Best. Thread. Ever.
Now, describe an elephant! :)
P
On 16-Jan-07, at 12:55 PM, Ian Turton wrote:
On 1/16/07, Raj Singh <[EMAIL PROTECTED]> wrote:
If you favor a Java component over SQL, C etc., Java Topology Suite
------------------------------
Message: 8
Date: Tue, 16 Jan 2007 22:15:37 -0800
From: Jason Birch <[EMAIL PROTECTED]>
Subject: Re: [Geowanking] Re: Opinions about GeoServer
To: [email protected]
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Paul Ramsey wrote:
Best. Thread. Ever.
Now, describe an elephant! :)
You have a strange affinity for elephants...
Elephant: Not a geoserver.
J
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The Open Planning Project
http://topp.openplans.org
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