Who runs this site
Mapper Tools (mapper.tools) is operated by Anderson Gomes Ferreira. contato@mapper.tools
How it works
The calculations run in your browser: the points you click and the files you load are not sent to our servers (details in the Privacy Policy).
Distances, bearings, midpoints, circles and polygon areas are geodesic: they are measured on the WGS 84 ellipsoid with Charles Karney’s algorithms, not on the flat picture of the map. UTM uses his Krüger series. The code is tested against published reference values.
Only the background map is fetched from outside the site: tiles from OpenFreeMap, built from OpenStreetMap data.
Where the data and rules come from
- Karney, “Algorithms for geodesics” (J. Geodesy, 2013) — distance, bearing, midpoint, circle, polygon area
- Karney, “Transverse Mercator with an accuracy of a few nanometers” (J. Geodesy, 2011) — UTM
- NIST Guide to the SI, Appendix B.8 — mile, nautical mile, foot, hectare
- RFC 7946: The GeoJSON Format
- OpenFreeMap — base map tiles
- OpenStreetMap copyright and license — map data
How we keep the content up to date
Each tool page lists its sources and the day we opened them. The numbers in the worked examples are computed by the same code as the tools.
What this site is not
These are calculation aids, not survey instruments. They measure on a mathematical model of the Earth and on the points you give them. For a legal boundary, engineering, navigation or aviation, use a licensed surveyor or the official chart.
Get in touch
Found a mistake, have a question or a suggestion? See the channels on the contact.
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