Contour Map Accuracy and Data Sources
Most people who have used the contour map generator found it an amazing tool and it has saved many of them thousands of dollars that they might have spent on a traditional survey. However, the tool uses open source data so accuracy cannot be guaranteed.
The elevation data is provided by Mapzen. The underlying data sources are a mix of open source data from around the world, as such, quality and accuracy varies from place to place. You can see the approximated resolution for your location in the map. View an accuracy map at this page for more detailed information.
Data provided by contourmapgenerator.com is purely informational.
This tool is based on and works thanks to products/services of the following projects, companies or people: Leaflet, D3.js, Axis Maps, Mapbox, Mapzen, OpenStreetMap, Google Maps, Danilo da Rosa and Magick Media.