[fdo-users] MapInfo provider

[Traian Stanev]

Quoting:
==
"Yes, to simplify the development, the FDO OGR provider does not parse full FDO statements, but
looks for a statement tree like: "<geom filter> AND <logical expr>" and supports either side missing
or swapped, but nothing else.

I have wanted to build full support for FDO expressions, but have not had the time or FDO knowledge to do so yet."
==

Yes this is true, I initially did this since those were the only queries one would reasonably expect from Map3D or MapGuide. I think we can improve this by taking the query translator from the SQLite provider. It extracts any geometric or ID queries from the filter and converts the remainder to an SQL statement to pass on to SQLite. In the OGR case we can pass the remainder SQL to OGR. The SQL translator code is a bit incomplete, and in the case of OGR would have to be slightly different, but the general idea would be the same.


Traian



________________________________________
From: fdo-users-bounces at lists.osgeo.org [fdo-users-bounces at lists.osgeo.org] On Behalf Of Kenneth Skovhede, GEOGRAF A/S [ks at geograf.dk]
Sent: Thursday, March 26, 2009 5:55 AM
To: FDO Users Mail List
Subject: Re: [fdo-users] MapInfo provider

Frank Warmerdam skrev:

On Wed, Mar 25, 2009 at 10:49 AM, Kenneth Skovhede, GEOGRAF A/S
<ks at geograf.dk><mailto:ks at geograf.dk> wrote:


That depends on what you want to accomplish.

I find that speed is very good, even better than SDF when using TAB files.
All the data I have tested with renders fine, but date/time columns are not
supported.



Folks,

I do believe that date/time support has been incorporated into MITAB and
the OGR bindings in recent versions of OGR.  If not it might be worth
filing a ticket on this.  Does the OGR FDO provider support date/time fields?
They are a relatively recent addition to OGR.



I'm using GDAL 1.4, so date/time columns might work with a more recent OGR/GDAL version.

But, the OGR only supports a geometry and a single logical expression.
It would be cool to have it support arbitrary FDO expressions.
If that is your target, I belive some of the other providers have much of
the logic for this,
and that it would be a better solution than a pure MI provider.



Is this an improvement that can be done right in the FDO OGR provider?



Yes, to simplify the development, the FDO OGR provider does not parse full FDO statements, but
looks for a statement tree like: "<geom filter> AND <logical expr>" and supports either side missing
or swapped, but nothing else.

I have wanted to build full support for FDO expressions, but have not had the time or FDO knowledge to do so yet.

Overall, I'd prefer to see the requirement for good mapinfo support drive
improvements to the FDO OGR provider (and perhaps OGR/MITAB)
rather than do something really custom.


I support that idea.


Best regards,


--
Regards, Kenneth Skovhede, GEOGRAF A/S