[postgis] Next Level Redux

[Frank Warmerdam]

Paul Ramsey wrote:

>Implementing the Web Feature Server is something I have been thinking
>about for a while, and there are two ways of thinking about it. 
>
>One is the way Frank is probably thinking of, which is to use the WFS as
>an abstraction layer for a bunch of different data sources. This makes
>great sense for his OGR library, which is already an abstraction layer.
>A WFS based on OGR gets all the OGR-supported data sets for free.
>
Paul,

Certainly I am eventually interested in an OGR based WFS; though; I wouldn't
really be in a strong position to implement transactional capabilities 
well.  This
works best when run against a real database - PostGIS in this case.

>I am also interested to hear what people think about WFS architectures:
>long-running processes, or one-shot CGI scripts? Probably the best
>possible performance would be from an Apache module, but that might be
>alot more work than is necessary, given that the parsing overhead for
>the client dealing with GML (!) results will probably vastly outweigh
>the retrieval/transformation overhead for the server.
>
It would depend on your language of implementation.  Because so much is
separated out into the database which has it's own concept a long running
process for maintaining some state and caching I would hope a light cgi-bin
impelementation would be fine.  Of course, I don't know too much about
how Java stuff is done in a web environment.  You certainly don't want to
start a JVM for each call.

>Of course, any WFS implementation will have the same problem which
>PostGIS has now: no clients! :) 
>
Well, there are a few WFS clients in existance now - including GeoMedia 
(or at
least an upcoming GeoMedia) but you are right that there wouldn't be too 
much.

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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