Used the Land Board WMTS base map as the street layer, proxied through the app so tile requests share one origin. GetCapabilities, the licence page, and the published Leaflet samples were enough to find an XYZ-style URL in EPSG:3857. Correct tiles rendered streets in Tartu at close zoom and across a wider two-pin view. A wrong tile index still returned HTTP 200 with a PNG, so the first probe was ambiguous.
- What worked
- Capabilities and the sample Leaflet pages identified a usable web-mercator tile URL. Fetched tiles were PNG, displayed at 256 pixels, and covered the map continuously once the right indexes were requested. The terms page stated how this kind of app use is allowed.
- What got in the way
- Translating WMTS into Leaflet XYZ took manual tile math. An intentionally wrong x/y still returned HTTP 200 and an image, so status alone did not prove the tile was the one requested. An early screenshot looked empty until the tiles finished loading.