[postgis-users] srid

Tue May 27 08:47:10 PDT 2008

Bob,
This is very interesting indeed.  I echo the sentiment of the utility of
Postgis's applicability.  I am currently developing an object oriented,
web library for creating environmental simulation models, using PostGIS
for much of the spatial relationships.  I have been toying with the idea
of an object design interface that used a combination of OpenLayers and
PostGIS to construct the actual relationships between the model
components, and to produce presentation quality flow diagrams at the
same time.

It looks as if yours is a commercial product, and is desktop based,
whereas mine is open-source and web-based, however, if you feel like
there are potential overlaps between our projects, feel free to contact
me offline at rburghol at ude.tv (last part of the address is a mirror
image).

Robert W. Burgholzer
Surface Water Modeler
Office of Water Supply and Planning
Virginia Department of Environmental Quality
rwburgholzer at deq.virginia.gov
804-698-4405
Open Source Modeling Tools:
http://sourceforge.net/projects/npsource/

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Bob
Pawley
Sent: Tuesday, May 27, 2008 10:41 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] srid

Hi Regina

You are right in thinking that the Postgis model can be useful in apps
other 
that geographic.

My little project is best summed up by the term Data Driven Design. 
Basically, I have created a prototype design model for designing
industrial 
plants (Oil and Gas, Pulp and Paper etc.) in PostgreSQL. For the
functions 
so far included, it works quite well.

The principal behind DDD is the wealth of information hidden within
basic 
data and the fact that there are fundamental scientific laws and wide 
ranging industry standards that can be employed to drive information,
which 
then drives further information until the design is complete.

What I am now doing is attempting to use the data to drive the graphic 
representation of the relational datastream. It wouldn't do to have a
data 
system, which will soon become self organizing and self generating, then

expect the user to manually draw the graphics one line, one circle and
one 
peice of text at a time.

If you're interested in learning more about my version of Data Driven
design 
check out my website www.automatingdesign.com.

I can easily see this technology being exploited for other industries
such 
as architectural and the facility design for the manufacturing industry
and, 
quite possibly, many others.

Bob

----- Original Message ----- 
From: "Paragon Corporation" <lr at pcorp.us>
To: "'PostGIS Users Discussion'" <postgis-users at postgis.refractions.net>
Sent: Monday, May 26, 2008 8:08 PM
Subject: RE: [postgis-users] srid

> Bob,
>
> I find it very interesting what you are trying to do.  I've always
thought
> that the whole spatial database model can be usefully applied to other
> domains besides geography.  It is nice to see someone trying to do
that.
>
> As far as ST_Transform goes,  still not quite clear how it plays into
your
> problem.  To be honest - I haven't really delved into the guts of what
> assumptions proj4 makes about geometry models except that it was
founded 
> on
> dealing with geography data.
>
> The whole Transformation infrastructure of PostGIS is based on proj4
and
> really the proj4text in the spatial_ref_sys as far as I know is all
that 
> is
> used by the PostGIS ST_Transform (srid for lookup).
>
> I would imagine to expand its use for other domains in a meaningful
way we
> would probably have to replace the field proj4text in spatial_ref_sys 
> tables
>
> with  - projmodeltext,  projmodel
>
> Where projmodel would define a library used for doing the spatial 
> transforms
> (in current case - they would all be filled in with 'proj4') , 
> projmodeltext
> would be the transformation params that the model needs
> and then any spatial reference systems based on the same function
model 
> can
> be transformed in between each other.
>
> Note: PostGIS actually deviates from the standard OGC spatial_ref_sys
> structure in that in the plain vanilla OGC Spatial_ref_sys,  proj4text

> field
> doesn't exist.
>
>
> Just my 2 cents,
> Regina
>
>
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Bob
> Pawley
> Sent: Monday, May 26, 2008 9:34 PM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] srid
>
> That is what I am attempting.
>
> I know of Visio. My thought of using Postgis is to, if possible, use
the
> functions that Postgis provides. In the very long range I was also
> considering the 3D aspect of Postgis.
>
> Your suggestion of using "boxes", presumably to provide reference
points 
> is
> my backup method, if ST_Transform isn't applicable.
>
> I would still like to consider ST_Transform as it appears to be a more
> flexible approach.
>
> Bob
>
>
> ----- Original Message -----
> From: "Chris Hermansen" <chris.hermansen at timberline.ca>
> To: "PostGIS Users Discussion" <postgis-users at postgis.refractions.net>
> Sent: Monday, May 26, 2008 6:05 PM
> Subject: Re: [postgis-users] srid
>
>
>> Or, in another direction... Bob, if your "geometrical data" is meant
to
>> be something like a "data flow diagram" or a "process diagram", you
can
>> surely do that with PostGIS.
>>
>> Doubtless you must be aware of tools like Visio (in Windoze) or Dia
(in
>> Linux or Windoze) that are made for drawing diagrams like "data
flow",
>> but nevertheless you've decided to put your data into PostGIS
instead.
>>
>> Then you probably want to make some "boxes" in your process diagram
>> appear above, below, to the right of, or to the left of, other boxes.
>>
>> To do that, you would need to define some kind of partial order on
the
>> boxes (this box is to the right of that box, etc).  This sounds like
a
>> topological sort to me.
>>
>> Presumably you could turn that topological ordering into some set of
>> offsets that could be applied to compute coordinates of each box.
>>
>> is that where you're trying to end up?
>>
>> Andy Anderson wrote:
>>> On May 26, 2008, at 3:06 PM, Bob Pawley wrote:
>>>
>>>> However, I attempting to interpret functions made for geographic
data
>>>> to use with geometric data.
>>>>
>>>> I have PostgreSQL tables which represent engineering processes.
>>>>
>>>> I want to display that data in a graphical form - hopefully using
>>>> Postgis - - - if I can translate the functions (or the Postgis
>>>> concept) into a form that I can use.
>>>
>>> Hmmm... if all you want to do is display X-Y data, I would suggest
>>> using geographic coordinates, e.g. SRID = 4326 (WGS84 datum), which
>>> most programs will display by default with X and Y rectilinear.
>>>
>>> However, you earlier said you wanted to use ST_Transform(geometry,
>>> integer), which implies you want to switch between different 
>>> geographies.
>>>
>>> So it sounds like you need to pick a particular projection for your 
>>> work.
>>>
>>> Is your geography spherical or spheroidal? If so, you might want to
>>> define your own datum. If not, you'll need to use a projection to a
>>> flat surface. What's more important, that it be conformal
>>> (equiangular) or equal area or that it preserve distance in one
>>> direction?
>>>
>>> -- Andy
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at postgis.refractions.net
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>
>>
>> -- 
>> Regards,
>>
>> Chris Hermansen         mailto:chris.hermansen at timberline.ca
>> tel+1.604.714.2878 . fax+1.604.733.0631 . mob+1.778.232.0644
>> Timberline Natural Resource Group . http://www.timberline.ca
>> 401 . 958 West 8th Avenue  . Vancouver BC . Canada . V5Z 1E5
>>
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