Interactive Explorer · The PostGIS Almanac

Layers

Buffer & proximity

A service-area question, the visual way: drop a point, grow a buffer, and count the facilities inside it — exactly what ST_Buffer + ST_DWithin do in SQL.

Radius

5 000 m

Count features inside the buffer

Spatial SQL console · DuckDB-WASM

The same ST_* SQL from the lecture, running entirely in your browser via DuckDB + the spatial extension — no server, no install. Tables: hospitals, provinces, districts, air_sites, rail_stations, airports.

DuckDB will start on first run…

Connect to a live PostGIS

This explorer ships a simplified snapshot of the teaching database so it runs on a static host with zero setup. A browser cannot open a raw PostgreSQL connection directly, so to query a live database you point a small read-only proxy at it and query through that.

The repo's interactive/export/export.sh shows the exact PostGIS SQL used to build these layers — run it against your own DB_URL to refresh the snapshot, or adapt it to add tables.

set -a && source .env && set +a   # provides DB_URL
cd interactive/export && ./export.sh

Click the map to set the buffer centre…

Loading real GIS layers…

Loading real Korean GIS layers…