Terrain + buildings + diffraction estimate; indoor penetration and reflections are not modelled.
Sources and data quality
Source completeness is unverified. Terrain is a mixed-source surface with residual canopy/building bias, not a guaranteed bare-earth DTM. Ground under buildings is inferred from nearby outdoor terrain; steep terrain limits accuracy. Missing building heights use the explicit assumption above.
Mapzen Terrain Tiles — SRTM, GMTED2010, ETOPO1 and regional contributors; Mapzen credits. Overture Maps / OpenStreetMap contributors, ODbL.
Map tiles and explicit city searches contact external providers. Calculations fetch terrain and buildings on the server. No field-survey accuracy is claimed.