[postgis] To Do List

Daniel Morissette morissette at dmsolutions.ca
Mon Jun 11 18:15:14 PDT 2001

Paul Ramsey wrote:
> Hi Frank,
> We're very much interested in seeing postgis hooked into Mapserver, as
> it would provide an instant interface to our datastore. And when
> conversing with the PHBs, an interface is important! (For some reason,
> people just don't get all excited about the SQL commandline, I have no
> idea why.) Is hooking into the maplayer.c abstraction difficult?

No, hooking into the maplayer.c abstraction is not very difficult.
There's about half a dozen functions you need to implement, and there's
already 3 implementations to learn from: the native Shapelib, SDE, and
the OGR one that I added.

However as you wrote...

Paul Ramsey wrote:
> Jeff is writing a loader/dumper (using shapelib, tee hee) so we're kind
> of using OGR already. Once OGR supports PostGIS, a simple wrapper to OGR
> will make more sense.

... I think adding support for PostGIS in OGR as Frank suggested
(instead of native PostGIS support in MapServer via the maplayer.c
interface) would be a better option for the short term at least.  This
will give PostGIS more exposure since MapServer, OpenEV, and all other
apps that support OGR will automatically have access to PostGIS.

It will also be simpler for you since you will have only one interface
to maintain (the OGR one), i.e. if something changes in MapServer's
maplayer.c you don't need to do anything.. only the OGR link has to be
updated (by me :) and all the OGR drivers continue to work.

On the other hand, we have to admit that OGR's object structure adds
some overhead, so if down the road you find that OGR adds too much
overhead then you can always go ahead and implement the native PostGIS
link in MapServer and tweak it to be as fast as can be.

My 0.02$ !
 Daniel Morissette               morissette at dmsolutions.ca
 DM Solutions Group              http://www.dmsolutions.ca/
  Don't put for tomorrow what you can do today, because if 
      you enjoy it today you can do it again tomorrow.

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