Cartes.io vs Ducks Unlimited

Cartes.io is an open-source platform for creating and sharing custom maps with markers, letting anyone plot points, GeoJSON shapes, and metadata without running their own server. Reading public maps and markers needs no signup — write access is optional and controlled per map, either open to anyone or gated behind a token issued when the map or marker is created. The API returns JSON by default and GeoJSON on request, and the project ships official Python and NPM packages alongside its hosted instance at cartes.io.

Ducks Unlimited publishes a public ArcGIS Feature Service listing its university and collegiate conservation chapters as geocoded point locations across the US and Canada. It's read-only and needs no API key — queryable with the standard Esri REST query syntax (WHERE clauses, field selection, spatial filters) and exportable as JSON, GeoJSON, CSV, KML, and several other GIS formats. The dataset is licensed under Creative Commons Attribution-NonCommercial 4.0, so results can be reused non-commercially with attribution.