Data sources
Updated August 22, 2026
| Dataset | Provider | Licence | Coverage | Used for |
|---|---|---|---|---|
| Cadastre INSPIRE WFS (CadastralParcel) | Dirección General del Catastro (Spain) | Free reuse with attribution | Spain (except Basque Country and Navarre) | Parcel geometry and official area in the planner and cadastre viewer |
| Open-Elevation (SRTM 30 m) | open-elevation.com / NASA SRTM | Public domain data; API free of charge | Global ±60° latitude | Slope and elevation profile |
| SunCalc (NOAA solar algorithms) | Vladimir Agafonkin / NOAA | BSD-2 | Global | Sun position, sunrise, sunset, shadows |
| ADA Standards for Accessible Design 2010 | US Department of Justice | Public domain | United States | Slope limits for accessible routes and ramps |
| CTE DB-SUA | Ministerio de Vivienda (Spain) | Public | Spain | Accessible itinerary slope limits |
| Engineering ToolBox material densities | engineeringtoolbox.com | Referenced values | Global | Gravel, sand and stone weight |
| NIST SP 811 unit definitions | NIST | Public domain | Global | Acre, foot and yard conversions |
| Land survey prices | Fixr (updated 2025-01), HomeGuide and Angi 2026 cost guides | Referenced figures | United States | Land survey cost estimator |
| Well drilling and septic prices | HomeGuide, Angi, The Well Guide, SepticTankHub 2026 cost guides | Referenced figures | United States | Well and septic cost calculators |
| Photography | Pexels | Pexels licence | — | Illustrative imagery (credits recorded internally) |
Dates next to each figure on the site show when it was last checked against its source.