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<P><FONT SIZE=2>OK,<BR>
I will begin the process of starting a sourceforge project to house the data models and supporting SQL functions, etc. It would be great if Abe can facilitate some space for some of this as well, I think that the sourceforge is a good way to go about managing contributions and so forth, but if geoloaded.com could host some demos/case-studies, that would be really great (if that is what you have in mind).<BR>
<BR>
What would we be trying to do, putting together/porting some data models for this kind of pipeline/hydro data? What would it be called, i.e., what would one call a generic class of data models that would encapsulate that which we are working on?<BR>
<BR>
r.b.<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: postgis-users-bounces@postgis.refractions.net on behalf of Abram Gillespie<BR>
Sent: Mon 1/14/2008 11:35 AM<BR>
To: PostGIS Users Discussion<BR>
Cc: <BR>
Subject: Re: [postgis-users] Pipeline Data Model<BR>
<BR>
All,<BR>
<BR>
These are all very interesting ideas. I have a proposal - I've been<BR>
meaning to get a site running at geoloaded.com (nothing there ATM),<BR>
and though sharing data models isn't *specifically* the idea I had in<BR>
mind, it's very much in the spirit of what I intend to do. I'm happy<BR>
to host anything the group manages to put together. I'm not clear on<BR>
the EULA of the data model I currently have in my possession, but if I<BR>
can, I will post my results at the site as soon as I have something.<BR>
<BR>
R.B.,<BR>
<BR>
I'm swamped right now but will be in touch as soon as I have a moment.<BR>
I live at 14th & Main BTW. Small world indeed.<BR>
<BR>
-Abe<BR>
<BR>
On Jan 14, 2008 7:47 AM, Burgholzer,Robert<BR>
<rwburgholzer@deq.virginia.gov> wrote:<BR>
> We might think to do a little divide and conquer strategy on the database that Abe has, perhaps recruiting a group of individuals to each sign up for a handful of tables to convert to postgres, and then upload them all to a sourceforge repository.<BR>
><BR>
><BR>
><BR>
> r.b.<BR>
><BR>
><BR>
> -----Original Message-----<BR>
> From: postgis-users-bounces@postgis.refractions.net on behalf of Chris Hermansen<BR>
> Sent: Sun 1/13/2008 12:47 PM<BR>
> To: PostGIS Users Discussion<BR>
> Cc:<BR>
> Subject: Re: [postgis-users] Pipeline Data Model<BR>
><BR>
><BR>
> Gustavo makes a great point here.<BR>
><BR>
> Having worked with workstation ArcInfo for many years, I have a kind of<BR>
> "conceptual library" of how to do common tasks in the field in which I work.<BR>
><BR>
> As I use PostGIS I have to re-learn this "conceptual library", based on<BR>
> the building blocks defined by OGC. I have to say that my general<BR>
> impression is that the OGC geoprocessing model sometimes necessitates<BR>
> some pretty complicated SQL to achieve what is relatively<BR>
> straightforward in workstation ArcInfo, an example being given in the<BR>
> Wiki on geometrically combining partially overlapping polygon geometries<BR>
> so as not to generate null geometries where only one or the other input<BR>
> geometry exists.<BR>
><BR>
> In our company, we are (slowly) working on some documentation that<BR>
> demonstrates how to accomplish "model tasks" in PostGIS.<BR>
><BR>
> One of the biggest challenges we face (and would face on platforms other<BR>
> than PostGIS as well) is cleaning up the cruft coming in from all the<BR>
> nasty shapefiles floating around out there. For example,<BR>
> self-overlapping polygon geometry, gaps between polygons that aren't<BR>
> supposed to be there, tiny noise components arising from unfiltered<BR>
> GPS-source data. I could go on :-)<BR>
><BR>
> Another area of challenges is where we want a different geometric<BR>
> outcome than provided for in the OGC standard. A simple example is<BR>
> first being surprised by, then dealing with, degenerate geometries or<BR>
> composite geometries generated by what seem to be fairly straightforward<BR>
> geometric operations. A more complex example is the example given above<BR>
> - most of the time, when we overlay partially overlapping geometries, we<BR>
> don't want null geometries as a result in locations where only one or<BR>
> the other input geometry exists, rather we want whatever geometry exists<BR>
> with the appropriate attributes set to null.<BR>
><BR>
> Another is creating new geometries from components - geometries from<BR>
> text files, polygons from lines and points, etc.<BR>
><BR>
> Two things I see discussed on this list that could be of interest in the<BR>
> future are topology and time travel. Way back when PostgreSQL was just<BR>
> Postgres I did some work with time travel; I can see real potential in<BR>
> the concept, for example as a framework for managing and reporting on<BR>
> environmental certification. However that's a big design issue even<BR>
> with time travel working :-) With respect to topology, I'm surprised<BR>
> how little I miss it; though there are people in our offices who find<BR>
> it's the only solution for fixing up really nasty shape files; ie<BR>
> convert the data to coverages and bang away at them using the polygon<BR>
> topology until either nothing is left or the problem is fixed.<BR>
><BR>
> Anyway. Whether the approach to sharing this kind of info is through<BR>
> separate projects or just a bit more input to the PostGIS wiki, it seems<BR>
> pretty worthwhile to me.<BR>
><BR>
> Gustavo Ces wrote:<BR>
> > You canīt export a geodatabase ( i supose your model is just that) by<BR>
> > odbc, because the geometric logic is not transfered ( can you export a<BR>
> > geodatabase in arcgis to postgis?) I think you have to rewrite the<BR>
> > model, adapting it to postgis. Is a hard work, but the you can use the<BR>
> > postgresql full potential ( triggers, views, etc.. ) to make your<BR>
> > model more powerfull, smaller and dynamic.<BR>
> > In my experience, this work simplifies the model, and you can make it<BR>
> > "real-time", user adapted, etc...<BR>
> ><BR>
> > Iīve posted a long time ago a question about postgis models. I imagine<BR>
> > all postgis community members working alone, creating complex<BR>
> > functions and schemas to solve their problems and... reinventing the<BR>
> > wheel. Perhaps itīs time to create especific projects to create ( or<BR>
> > traduce ) schemas and functions for various cases. I know the wiki,<BR>
> > but i think in environmental members creating schemas, functions to<BR>
> > solve environmental questions( for instance). At this time each of<BR>
> > them has to walk his way alone ...<BR>
> ><BR>
> > Itīs just an opinion :)<BR>
> ><BR>
> > Gus<BR>
> ><BR>
> > _______________________________________________<BR>
> > postgis-users mailing list<BR>
> > postgis-users@postgis.refractions.net<BR>
> > <A HREF="http://postgis.refractions.net/mailman/listinfo/postgis-users">http://postgis.refractions.net/mailman/listinfo/postgis-users</A><BR>
><BR>
><BR>
> --<BR>
> Regards,<BR>
><BR>
> Chris Hermansen · <A HREF="mailto:clh@timberline.ca">mailto:clh@timberline.ca</A><BR>
> tel:+1.604.714.2878 · fax:+1.604.733.0631<BR>
> Timberline Natural Resource Group · <A HREF="http://www.timberline.ca">http://www.timberline.ca</A><BR>
> 401 · 958 West 8th Avenue · Vancouver BC · Canada · V5Z 1E5<BR>
><BR>
> C'est ma faįon de parler.<BR>
><BR>
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