Connect to ESRI Personal Geodatabase

[Mike Davis]

Thats pretty much what I was expecting.  To be honest, I have been
using a lot of shapefiles that aren't indexed so I am not one to harp
on performance.  I was mainly concerned about the overhead ODBC might
cause.  I've never used ODBC in a high performance application
(something other than a basic PHP driven web site) so I am not really
familiar with how it responds under load.

If someone can foreward me a copy of the proposal I will see if I can
find any funding.

On 7/6/05, Frank Warmerdam <fwarmerdam at gmail.com> wrote:
> On 7/6/05, Frank Warmerdam <fwarmerdam at gmail.com> wrote:
> > On 7/6/05, Mike Davis <mike.and.kerry at gmail.com> wrote:
> > > Funding things where I work is like pulling teeth, but I will inquire
> > > with the "powers that be" to see if it is possible, this is a feature
> > > we would really like to have (especially if the performace is close to
> > > that of shapefiles).
> 
> Mike,
> 
> There are two main issues affecting performance.
> 
> 1) Spatial indexing.  Personal geodatabase does have a spatial
> index table associated with spatial tables.  If we can properly utilize
> this we ought to be able to grab small spatial regions out of big tables
> effeciently.  If not, it will be as corresponding slow as a shapefile would
> be without a spatial index.  I'm not really confident I can utilize the
> spatial index yet though.  I looked at a sample file Howard provided,
> and the index table just had 0's and -1's in the spatial index table.
> I don't know if I was using too old a version of MS Access to look at it,
> or if it wasn't built or what.
> 
> 2) ODBC and OGR translation overhead.  Both of these layers add
> significant performance drag.
> 
> I can't give any real guarantees for performance, but if we can get
> spatial indexing working it shouldn't be too much worse than direct
> shapefiles.
> 
> Best regards,
> --
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
>