[postgis-users] PostGIS Conceptual and Phisical Modelling

Carlos Andrade carlosviansi at gmail.com
Wed Oct 26 13:07:19 PDT 2011

Dear Sandro and Peter,

Thank you both for your help.

I took some time researching the documentation and the web, and so far I've
learned a lot based also on the SQL-MM for both Topology and the one
suggested previously.

I have one last question that has been taking me a lot of effort to figure
out. If could someone tell me if this is possible I'd really appreciate.

For our assignment, we were interested on, say, get a picture from google
maps which has, among many things 3 buildings. We wanted to use some program
to make these 3 buildings turn into for example a polygon or that we could
draw polygons above them and also few dotes and lines. We also didn't want
to let the other information of the map go to waste, so we wanted all the
map to be saved on a shapefile so that it could be loaded at postgis 1.3.6
on a postgrees 8.4. Note that, in case I could turn all the map into a
shapefile, we would still need to use some sort of ID on the geometry forms
we are actually interested or it would be hard to find it out inside postgis
(or so I believe).

I found out that PostGIS could load shapefiles based on ESRI .shp and other
extensions for attributes, etc, but I've did not find yet a tool that could
take as input the google maps image, and let me save it as a shape file to
be directly loaded on the PostGIS. Is that possible?

I've dowloaded an ArchGis 10 trial and have been trying to use ArchMap, and
ArchCatalog  or ArchMap (web) to try to figure things out, but so far I
wasn't very lucky.

I saw few shapefiles even from my country and state on shapefiles, but they
do not hold this sort of specific information (I'm actually trying too find
my university campus on map and put it into shape files).

Another thing I was curious and still didn't find out is if 1.3.6 did not
support topology by that time. Since my university computers only have
postgis on this version I'm "stucked" on it and have not been able to use

Thank you!

Carlos Andrade

2011/10/17 Sandro Santilli <strk at keybit.net>

> On Mon, Oct 17, 2011 at 01:24:43AM -0200, Carlos Andrade wrote:
> > I came across this presentation while searching for it:
> >
> http://oslandia.org/postgis_paris_juin_2011/postgis_paris_topology_santilli.pdf
> >
> > Is anyone aware where can I find the tool used for this presentation or
> even
> > more information about how to model geographic data?
> I've been using QGis for the display the topology and PostGIS functions
> to edit it. Topology model is defined by ISO/SQL-MM document.
> > I've search the list
> > here as well but I only found a sugestion about DB Designer, and i'm not
> > quite sure if that was the tool used on that presentation or if it would
> be
> > available for us (we're just students, we can't afford a pay to use tool,
> > nor it be feasable to buy just for one school assignment).
> Pencil and paper are the best tools out there.
> It may be too much old school but I'd suggest using Entity-Relationship
> diagrams for a start. There's a nice ER diagram about the topology model,
> for example, under the topology/ER/ directory of the PostGIS source tree.
> --strk;
>  ()   Free GIS & Flash consultant/developer
>  /\   http://strk.keybit.net/services.html
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