Tool

What it does

calculate_curvature

Calculates how much of a distant target the Earth's curvature hides, from the surface distance, the observer's eye height, the target's height and an assumed refraction coefficient.

get_horizon_distance

Gives the distance to the horizon from an eye height above a smooth sphere, and how far a taller object such as a mast stays in straight sight.

compare_flat_map_distance

Compares the distance between two cities on a north-polar flat-Earth map with their great-circle distance over a sphere.

get_flight_distance

Calculates the great-circle distance between two places in kilometres, miles and nautical miles, with the initial and final compass bearings.

get_sun_position

Calculates the Sun's altitude and compass bearing at a place, date and UTC time, with the shadow of a 1 m upright and the day's sunrise and sunset in UTC. A place is one of the website's 20 cities or a latitude and longitude; without a date and time the result is for the current moment.

get_daylight_hours

Calculates the length of daylight at a place on a date, with sunrise and sunset in UTC, for the UTC day from midnight to midnight.

compare_true_size

Shows how much a Mercator map distorts a country's area, from its real area and the latitude it is drawn at.

find_claims

Searches the website's tested claims and flat-earth investigations, or returns one by id.