Apps & dashboards
Interactive map applications: Streamlit, pydeck and the browser budget that decides what they can show.
An interactive map application is a rendering budget with some analysis attached. Fifty thousand features draw as GeoJSON without thinking about it; half a million need WebGL and care; five million need tiles or aggregation, because the limit is memory on the client rather than bandwidth — which is why sending it faster does not help.
The rest of the topic is about state and reruns. Streamlit reruns the whole script on every interaction, so anything expensive has to be cached and anything stateful has to be stored deliberately. pydeck and MapLibre move the drawing onto the GPU but not the memory problem. And the map is usually the part people click first, so the interaction model matters as much as the layer.
The pages below cover the frameworks, the layer types, caching and state, and the specific ways an app becomes unusable as the data grows.
🧭 Start with the concepts
The ideas the how-to guides below assume you already have.
- Spatial Dashboards Explained: When an App Beats a Map Image
- Streamlit, Dash or Panel: Choosing a Framework for a Map App
- Reruns and State Explained: Why Your Map App Redraws Everything
- What a Map App Can Afford to Send to the Browser
- Notebook, App or Report: Choosing How to Ship an Analysis
- Sharing a Map App: Public, Private and In Between
⚙️ Then do the task
Step-by-step walkthroughs with code you can copy and adapt.
- How to Build a Streamlit App with an Interactive Map
- How to Add Filters and Widgets That Drive a Map
- How to Cache Spatial Data in a Map App
- How to Render a Million Points in a Map App with pydeck
- How to Let Users Draw an Area of Interest in a Map App
- How to Add a Download Button for Filtered Spatial Data
Show every how-to guide in this topic
🔧 When it breaks
The errors this topic produces, with the cause explained rather than just the command.
Learning paths through this topic
A curated route rather than a list — the guides in the order that builds on itself.
Related topics
Subjects that keep coming up alongside this one, most overlap first.