[Geowanking] Re: Re: Opinions about GeoServer (Paul Ramsey)

Wed Jan 17 09:31:01 PST 2007

> 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
> scott at davisworld.org
> 
> 
> Original Post:
> 
> On 1/16/07, andrew at cs.uoregon.edu <andrew at cs.uoregon.edu > 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 <pramsey at refractions.net>
>> Subject: Re: [Geowanking] Re: Opinions about GeoServer
>> To: geowanking at lists.burri.to
>> Message-ID: <03265FD3-DE82-43A1-92ED-8CAAE44199FF at refractions.net>
>> 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 <raj at rajsingh.org> 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 <jb-geowanking at jasonbirch.com>
>> Subject: Re: [Geowanking] Re: Opinions about GeoServer
>> To: geowanking at lists.burri.to
>> Message-ID: <45ADBF09.2000108 at jasonbirch.com>
>> 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
>>
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> Geowanking mailing list
>> Geowanking at lists.burri.to
>> http://lists.burri.to/mailman/listinfo/geowanking
>>
>>
>> End of Geowanking Digest, Vol 38, Issue 30
>> ******************************************
>> _______________________________________________
>> Geowanking mailing list
>> Geowanking at lists.burri.to
>> http://lists.burri.to/mailman/listinfo/geowanking
> 
> _______________________________________________
> Geowanking mailing list
> Geowanking at lists.burri.to
> http://lists.burri.to/mailman/listinfo/geowanking
> 
> !DSPAM:1003,45ae5199154231804284693!
> 

-- 
Chris Holmes
The Open Planning Project
http://topp.openplans.org
-------------- next part --------------
A non-text attachment was scrubbed...
Name: cholmes.vcf
Type: text/x-vcard
Size: 269 bytes
Desc: not available
URL: <http://geowanking.org/pipermail/geowanking_geowanking.org/attachments/20070117/554f92b6/attachment-0003.vcf>