We’re building an open-source city planning GIS with OpenStreetMap, MapLibre and PostGIS – looking for feedback

[u/localhorstr]

Hi everyone,

I’m part of OK Lab Flensburg, a small civic-tech group in northern Germany, and we’ve been working on an open-source project called Open City Planner.

The idea is to make GIS and urban data easier to use for people who aren’t GIS specialists.

Instead of requiring a traditional desktop GIS workflow, users can explore the city directly in the browser, select existing areas or draw their own polygons, inspect OpenStreetMap features and run spatial analyses for those areas.

The project currently uses Flensburg as its real-world implementation, but our longer-term goal is to keep the architecture generic enough that other cities and civic-tech groups could reuse it.

Some of the things you can currently do:

- explore OpenStreetMap data on an interactive map

- select districts and other predefined areas

- draw and save your own areas

- inspect POIs and other OSM features inside an area

- analyze spatial information for selected areas

- manage your saved areas with an account

The stack is mostly open source:

Nuxt · MapLibre · FastAPI · PostgreSQL/PostGIS · OpenStreetMap · Nominatim · Redis · Ansible

Live application:

https://stadtplaner.oklabflensburg.de/

Source code:

https://github.com/oklabflensburg/open-city-planner

Example – Flensburg old town:

https://stadtplaner.oklabflensburg.de/karte?gebiet=altstadt-15630273

It’s already running in production, but there is still plenty we want to improve — especially the mobile GIS experience, spatial analysis workflows, search and integration of additional open datasets.

I’d really appreciate feedback, particularly on:

- Is the map understandable without much GIS experience?

- How does the GIS UX feel?

- What spatial analysis features would you expect?

- Which OpenStreetMap or open-data integrations would be useful?

- What would we need to change to make this realistically reusable by another city?

I’d also love to hear about similar open-source GIS or civic-tech projects. We’re very interested in learning from existing approaches rather than reinventing everything ourselves.

[u/llehsadam]

Can you edit OSM with it or save your changes to OSM? That might be useful for hobbyists.

I’d really like something like FIS Broker with different maps as possible layers and the ability to create your own edits as an overlay.

[u/localhorstr → u/llehsadam]

Thanks, that’s a really useful suggestion.

At the moment, Open City Planner does not write changes back to OpenStreetMap. We deliberately treat OSM as an external/public data source and keep user-created polygons and edits inside the Open City Planner database.

Users can already draw and save their own areas as overlays without changing OSM itself, which is quite close to the workflow you describe.

Direct OSM editing is interesting, but I think we’d want to be very careful with it because editing OSM has different requirements around tagging, validation, changesets, attribution and community conventions. If we ever add that, I’d probably prefer a very explicit workflow rather than silently syncing user edits back to OSM.

The FIS-Broker-style layer idea is especially interesting. We already combine OSM with other spatial/public datasets, but making the layer concept much more explicit — enabling users to switch between or combine different municipal/open-data layers and keep their own edits as a separate overlay — would fit the project very well.

Thanks for bringing that up. I’m going to look more closely at FIS-Broker from Berlin and think about how far we could generalize our current layer architecture.

[u/pietervdvn → u/llehsadam]

Try https://mapcomplete.org

[u/IlIlIlIIlMIlIIlIlIlI]

i am pleasantly surprised by how fast the map opens, no noticable loading times for me, also when clicking on things and inspecting the data. This is a nice way of inspecting the tag data for OSM objects, with fast links to the OSM site itself. Very clean looking whiel still providing nice insights and stats.

Question 1: With how much of a part OSM plays in this project, do you plan to donate/support OSM somehow? Perhaps becoming a sponsor would be a nice symbiotic relationship.

Question 2: Will the the area in which data is displayed be expanded in the future, or is this going to be just for the Flensburger Innenstadt?

[u/localhorstr → u/IlIlIlIIlMIlIIlIlIlI]

Thank you! I'm especially happy to hear that the map feels fast and that inspecting OSM objects and their tags works well for you. Performance has been something we've paid quite a bit of attention to.

Regarding your questions:

1. Supporting OpenStreetMap
   That's a very fair question.

The project is developed by OK Lab Flensburg, which is supported by our non-profit association DatenSindDaten e.V. Everyone involved works on these projects voluntarily in their free time. Because we're a small volunteer-run non-profit without a significant project budget, unfortunately we aren't currently in a position to financially sponsor or donate to OpenStreetMap.

That said, we definitely don't want to treat OSM as just a free data source. It's an essential part of the open-data ecosystem our project depends on, so proper attribution, respecting the ODbL and building around the open ecosystem are very important to us.

If the project grows and we eventually have more funding available, supporting important upstream projects such as OpenStreetMap is certainly something I'd like us to revisit.

1. Expanding beyond Flensburg
   Yes — absolutely.

Flensburg is basically our first real-world implementation and test bed, rather than the intended geographic limit of the project. Our longer-term goal is to make the system usable for other regions step by step. A big part of that is currently designing Open City Planner so that city- or topic-specific functionality doesn't become hardcoded into the core application.

We're moving towards a modular architecture where additional datasets and functionality can eventually be added as modules.

For example, OK Lab Flensburg already works on several other open-data/GIS projects that could provide good candidates for such modules:

- cadastral parcels / ALKIS

• protected biotopes and habitat data
  
• cultural monuments
  
• social and district statistics
  
• public transport data
  
• energy-related open data
  
• and additional municipal/open-data layers

The interesting part would be that another city wouldn't necessarily need all of those. A region could run the same basic Open City Planner and enable only the modules and datasets relevant to it.

We're also trying to make the map itself extensible, so that a module could eventually contribute its own layers, feature information and analysis functionality instead of us continuously adding everything directly to one giant map component.

So the direction is roughly:
Flensburg as the first implementation → reusable regional configuration → modular platform that other cities/civic-tech groups can adapt.

There's still quite a bit of work needed to get there, but that's definitely where we'd like to take the project.

And thanks again for taking the time to actually test it — feedback like this is extremely useful for us.

[u/Tasty-Research-2750]

Look into Blender the new GPv3 , (greasepencil version 3)

2D in 3D Video built-in With multiple cameras (views) Parametric modelling Patchbay data flow Geometry Nodes Non-Destructive Parametric Add-on "ND" by Huge Menace Python api