Re: [udig-users] Oracle: sdo_aggr_mbr vs user_sdo_geom_metadata

[Jody Garnett <jody.garnett@xxxxxxxxx>]

Thanks Simon; I better make a geotools bug report and gather up your suggestion:
- https://jira.codehaus.org/browse/GEOT-3251

I actually do know what sdo ordinates mean - the data structure is used as part of SDO_GEOMETRY and there is some code in GeoTools to parse such things which I wrote a while back.

Jody

On 19/08/2010, at 7:16 PM, Simon Greener wrote:

> Greetings,
> (Jodie, I'm on holidays in NZ. Back Sept 3rd.)
> I learned  when programming GeoRaptor that you
> can access the root mbr of the Oracle RTree
> in user_sdo_index_metadata (column sdo_root_mbr).
> This is an sdo_geometry object. However,
> when it contains the mbr of a gedetix layer,
> we haven't worked out what the
> sdoordinates mean, as yet.
> But is is blindingly faat: better tahn aggr union.
> Code is in metedatatool.java in sourceforge repository.
> best i can do.
> simon
> On Thu, 19 Aug 2010 14:23:32 +1000, Jody Garnett <jody.garnett@xxxxxxxxx> wrote:
> 
>> Hi Brandon.
>> 
>> We had the previous version of our oracle support use the geom
>> metadadata table; and I after treading the oracle manuals I though
>> this was the correct approach to determine bounds.
>> 
>> I got lots of negative feedback; apparently this table is not often
>> filled in with the correct information and cannot be trusted.  With
>> that in mind, when geotools created their "jdbc-ng" rewrite for oracle
>> support they did not even considering taking the geom metadata table
>> code used previous.
>> 
>> If you like we can make the feature request for GeoTools and see what they say.
>> 
>> With respect to SELECT SDO_AGGR_MBR ... I had thought that we avoided
>> doing this for uDig 1.2.0 - instead assuming a default max extent
>> based on the coordinate reference system.
>> 
>> When Maurcio returns from vacation we can ask him, he performed the
>> oracle testing for 1.2.0.
>> 
>> 
>> Jody
>> 
>> On Thu, Aug 19, 2010 at 4:37 AM, Bergenroth, Brandon
>> <bbergenroth@xxxxxxx> wrote:
>>> I have yet to see uDig (including 1.2.0) use user_sdo_geom_metadata,
>>> instead, it seems to always insist on running
>>> 
>>> SELECT SDO_AGGR_MBR(GEOMETRY) FROM BIG_SPATIAL_TABLE
>>> 
>>> for every table in the schema.
>>> 
>>> Will uDig ever use user_sdo_geom_metadata?  Running a full table scan on
>>> every spatial table makes it pretty much useless for anything but a
>>> trivial amount of data.
>>> 
>>> Thanks,
>>> Brandon
>>> 
>>> 
>>> 
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> 
> 
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