See it before you download it.

Every public map layer, live on one canvas. Hover to preview, pin to combine, draw an area to see what covers it — and leave with a working map, not a zip file.

1

Hover any dataset — the real layer renders instantly on the shared map. No thumbnails, no clicking through.

2

Pin the layers you like — they compose into one live map in the workbench tray.

3

Leave with a map — a working layers.json, a share-link, or GeoJSON. Not a zip you have to pray over.

Developer

The catalog, machine-readable

One JSON per catalog drives this whole site — generated by build_catalog.py; switch catalogs with ?catalog=md / ?catalog=ca.

Query any dataset (ArcGIS REST)

## live count
curl "https://mdgeodata.md.gov/imap/rest/services/Hydrology/MD_Floodplain/FeatureServer/0/query?where=1%3D1&returnCountOnly=true&f=json"
## geojson slice (note: f=geojson lowercases field names; always outSR=4326)
curl "…/FeatureServer/0/query?where=1%3D1&outFields=*&outSR=4326&f=geojson&resultRecordCount=100"

Server notes

llms.txt

This catalog is AI-readable: point an agent at catalog-md.json; each record carries endpoints + shelf + tags. DCAT/OGC Records feeds are the production path (see RECIPE §3.3).