[postgis-users] Topology question

[Lars Aksel Opsahl]

>From: postgis-users <postgis-users-bounces at lists.osgeo.org> on behalf of Simon Greener <simon at spdba.com.au>
>Sent: Wednesday, March 22, 2023 11:20 AM
>To: PostGIS Users Discussion <postgis-users at lists.osgeo.org>
>Subject: [postgis-users] Topology question
>
>I'm proposing PostGIS for a customer with qGIS as an editing tool. The question of topological editing is to be addressed. While there are topological editing tools in qGIS I haven't found any examples of people using PostGIS topology (with/without qGIS). Does anyone know of any reference sites where PostGIS topology is being used in production?
>Thanks in advance
>Simon

Hi

NIBIO has been using Postgis Topology for many years now in production and for many types of different layers. There are still bugs to work with in Postgis Toplogy, but with good help from Sandro Santilli this has been working very well. When I asked last year I got a replay from 6 people that was using this in production.

We don't use QGIS for updating for data in Postgis Topology , because one of the reasons for using Postgis Toplogy was to make maps more easy to update for non gis people in addition to be able to handle overlap and gap in much better way, than when using simple feature. To update maps you should not need install QGIS or other 3. parity software, but just click on link, login and start to draw new borders. From QGIS I use TopoViewer from dbmanger to view and check Postgis Topology databases and that is very nice.

Non gis people seems like the idea of just adding new borders, rather having to move old borders with many points around. Not moving borders also secures us much better against data corruption of old data.

The idea of adding and removing borders fits perfectly with the Postgis Topology model and that makes the client much simpler also and it means that we can have simple generic web browser clients, based on a very simple API.

The other thing we use Postgis Topology for is to clean and merge big simple feature layers .

Yes, we need to get more focus Postgis Topology and also the limitations, costs and data corruption related usage of Simple Feature.

So I think, we need more workshops and talks around these issues on for instance on Foss4G conferences around the world and other forums.

Here are some links with more info

https://gitlab.com/nibioopensource/topo_update-app-foss4g2022
https://gitlab.com/nibioopensource/pgtopo_update_gui
https://gitlab.com/nibioopensource/pgtopo_update_rest
https://gitlab.com/nibioopensource/pgtopo_update_sql
https://gitlab.com/nibioopensource/resolve-overlap-and-gap

Lars
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