[fdo-internals] RE: FDO Function SpatialExtents

[Jason Birch]

SDO_DIMINFO in the SDO_GEOM_METADATA_TABLE (which has a bunch of user, etc aliases) stores the extents of each layer.  However, this isn’t guaranteed to be the  data extents in real-world situations.

 

SDO_INDEX_METADATA_TABLE appears to store information about the MBR, but I’m not sure how to decode it.  None of the entries in my database contain usable values in SDO_*_EXTENTS fields or in the SDO_ROOT_MBR field (that I can tell).  Do you have to read the value of the SDO_NL_INDEX_TABLE, and then pull the value from that?

 

Jason

 

From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Orest Halustchak
Sent: Monday, November 17, 2008 14:45
To: 'fdo-internals at lists.osgeo.org'
Subject: Re: [fdo-internals] RE: FDO Function SpatialExtents

 

Oracle saves the root mbr in one of the metadata tables. I don't have access at the moment to check.

Orest.

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From: fdo-internals-bounces at lists.osgeo.org 
To: FDO Internals Mail List 
Sent: Mon Nov 17 14:54:09 2008
Subject: RE: [fdo-internals] RE: FDO Function SpatialExtents 

Can you help me little more, how to get it from R-TREE ?

I know of SDO_TUNE.Extent_OF which is faster for some types of data.

 

BTW, so far I tested , Map calls it twice, once together with Count, second time only SpatialExtents.

 

Thanks,

Haris

 

From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Orest Halustchak
Sent: Monday, November 17, 2008 11:22 PM
To: FDO Internals Mail List
Subject: [fdo-internals] RE: FDO Function SpatialExtents

 

Hi Haris,

 

Map3D asks for the spatial extents first before fetching any of the geometry. The spatial extents will define the extents of the window. The spatial extents function needs to be very quick in this case. For Oracle, you could get it from the r-tree.

 

Thanks,

Orest.

 

From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org] On Behalf Of Haris Kurtagic
Sent: Monday, November 17, 2008 5:36 PM
To: FDO Internals Mail List
Subject: [fdo-internals] FDO Function SpatialExtents

 

Hi,

 

I have implemented support for SelectAggregates in King.Oracle.

I am testing SpatialExtent function and I need help in understanding how clients, MAP 3D , is using it. I am not sure if I understand how is it supposed to be used.

 

I have implemented function using Oracle SDO_AGGR_MBR. That is rather slow process .

What I noticed is that MAP 3D 2009 is calling FDO command SelectAggregates with SpatialExtents function.

That makes rendering of layers very slow in MAP 3D.

 

I know I am asking about non-open source client like MAP 3D but from what I see makes me wonder if I understand SpatialExtents function correctly.

 

Thank you,

Haris

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