[postgis] Re: [mapserver-users] Building maps without a .map using MapScript only

[Frank Warmerdam]

Daniel Morissette wrote:
> Also, about SDE being the only DB format available, I think that's not
> true any more... I think Frank Warmerdam added support for the new
> PostGIS (http://postgis.refractions.net/) database in OGR... so you
> could use the OGR2OGR tool to load your layers in a PostGIS database,
> and then use MapServer + OGR to serve maps from that database.  I'm not
> sure what the status of all those components is though... perhaps Frank
> can comment on this.

Folks, 

It should now be possible to use PostGIS as a spatial database for MapServer
pre3.5 via the OGR linkage, as long as you build and install OGR from the
current CVS source. 

I tried setting up a mapserver demonstration using OGR and PostGIS, but 
got bogged down in some sort of database permissions problem when running
as nobody and never got back to fix it. 

Note that this OGR support for PostGIS and PostGIS itself are quite new, so
this approach is really only suitable for someone willing to risk some 
pain getting things going.  However, the PostGIS spatial quieries can be
rocket fast, and I think this is a promising approach for MapServer users
wanting to use a DBMS but without SDE.  I should warn though that any
queries that actually pull alot of data out of PostGIS are going to be kind
of slow due to the inefficiencies of all the data handling within PostGIS, 
and in OGR.  Converting the internal representation of stuff to text (OGC
WKT), pulling it back one record at a time into OGR.  Converting to 
OGRFeatures.  Converting those to shapes structures within MapServer.  

If performance becomes an overriding concern we might eventually want to
build a direct MapServer to PostGIS linkage, as well as look at optimized
approaches to getting the data out. 

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

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