Filtering with ST_AREA

[Kang Mann Ern]

Some javascript/style in this post has been disabled (why?)

Hey guys,

 

I've been trying to get GeoTools to use the PostGIS ST_AREA function

when doing a SELECT query for some time so that fewer results are returned,

e.g. "SELECT * FROM table WHERE ST_AREA(the_geom) > 200;",  but have

 had no luck so far.

 

FilterFactory.function("ST_AREA", ...) gives an exception saying "St_area

cannot be found". If I replace "ST_AREA" with "AREA", it does post-fetching

filtering instead which is not what I wanted (I verified this by having PostgreSQL

log all queries - ST_AREA never shows up in the where clause).

 

I've searched through the sources and google but can't find mention of using

ST_AREA with GeoTools anywhere.

 

Was hoping to get some ideas on how this could be done.

 

Cheers,

riverfullofgood

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[Mauricio Pazos]

On Wednesday 07 October 2009 01:43:15 am Kang Mann Ern wrote:
> FilterFactory.function("ST_AREA", ...) gives an exception saying "St_area
> cannot be found"
Hi, The function name should be "area", so test using
 FilterFactory.function("area", ...)

cheers
--
Mauricio Pazos
www.axios.es

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[Kang Mann Ern]

Hi, thanks for the reply. I already tried that but it seem GeoTools stills
queries
everything from the database and filters them locally.  I checked this by
logging
all queries to the database.

I was thinking of maybe using the SQLBuilder to construct a query manually
but
that doesn't seem like the optimal way of doing it.

Could you give me a hint about an alternate way of doing this?

Cheers

--------------------------------------------------
From: "Mauricio Pazos" <[hidden email]>
Sent: Wednesday, October 07, 2009 5:42 PM
To: <[hidden email]>
Cc: "Kang Mann Ern" <[hidden email]>
Subject: Re: [Geotools-gt2-users] Filtering with ST_AREA

> On Wednesday 07 October 2009 01:43:15 am Kang Mann Ern wrote:
>> FilterFactory.function("ST_AREA", ...) gives an exception saying "St_area
>> cannot be found"
> Hi, The function name should be "area", so test using
> FilterFactory.function("area", ...)
>
> cheers
> --
> Mauricio Pazos
> www.axios.es
>

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[Mauricio Pazos]

On Wednesday 07 October 2009 12:13:03 pm Kang Mann Ern wrote:
> Hi, thanks for the reply. I already tried that but it seem GeoTools stills
> queries
> everything from the database and filters them locally.  I checked this by
> logging
> all queries to the database.
>
I guess you have fund a bug. To report http://jira.codehaus.org/

> I was thinking of maybe using the SQLBuilder to construct a query manually

I think the problem is in the postgis data store, if I am right this approach
wont work. Probably the problem is the FilterVisitor implementation.

> but
> that doesn't seem like the optimal way of doing it.
>
> Could you give me a hint about an alternate way of doing this?
>
> Cheers


--
Mauricio Pazos
www.axios.es

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[Kang Mann Ern]

Hi, sorry for the late reply. Thanks a lot for your help,
I'll make a bug report on that link.

Cheers!
--------------------------------------------------
From: "Mauricio Pazos" <[hidden email]>
Sent: Wednesday, October 07, 2009 9:18 PM
To: "Kang Mann Ern" <[hidden email]>
Cc: <[hidden email]>
Subject: Re: [Geotools-gt2-users] Filtering with ST_AREA

> On Wednesday 07 October 2009 12:13:03 pm Kang Mann Ern wrote:
>> Hi, thanks for the reply. I already tried that but it seem GeoTools
>> stills
>> queries
>> everything from the database and filters them locally.  I checked this by
>> logging
>> all queries to the database.
>>
> I guess you have fund a bug. To report http://jira.codehaus.org/
>
>> I was thinking of maybe using the SQLBuilder to construct a query
>> manually
>
> I think the problem is in the postgis data store, if I am right this
> approach
> wont work. Probably the problem is the FilterVisitor implementation.
>
>> but
>> that doesn't seem like the optimal way of doing it.
>>
>> Could you give me a hint about an alternate way of doing this?
>>
>> Cheers
>
>
> --
> Mauricio Pazos
> www.axios.es
>

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[Mauricio Pazos]

On Friday 09 October 2009 05:03:33 am Kang Mann Ern wrote:
> Hi, sorry for the late reply.
no problem
> Thanks a lot for your help,
> I'll make a bug report on that link.
>
Good, it is the first step for your solution
Usually, the priorities of open source project don't match with our goals. I
don't know your project and the impact of this issue, but  in my experience, I
have got good result downloading the source and adjusting it to our
requirements or solving bugs (of course, previously evaluate effort, risk
analysis, etc ), we save a lot of person-hours.

> Cheers!
Good luck!
--
Mauricio Pazos
www.axios.es

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