Circle produces ellipsis (oval) geometry

import circle from '@turf/circle';

then i create a circle:

let coords = [
    55.837150763618574,
    37.48126387596131,
];

let radius = 70; // in meters

let options = {
    steps: 32,
    units: 'kilometers',
};

let c = circle(coords, radius / 1000, options);

and if i use circle’s geometry coordinates to build a polygon and put in on some map:

console.log(c.geometry.coordinates)

it in fact looks like an ellipsis, not circle.

[stebogit]

OK @artuska I found the issue. The data in Turf is definitely treated differently than in Leaflet (with all LatLgn stuff), the only common ground is GeoJSON.

If you try

var turfCircle = turf.circle([center[1], center[0]], radius / 1000, turfCircleOptions);
L.geoJSON(turfCircle).addTo(map);

that works beautifully.

The L.Polygon function does not work like @turf/helpers|polygon. You need to use the L.geoJSON method on the GeoJSON output of Turf circle.

[MaxDragonheart]

But anyway — my geometry appears as a circle in Syria but as an ellipsis in Moscow — this is totally strange.

Have you checked the projection system of your project? MapBox use EPSG 3857, this SR amplify the deformation in data as you move away from equator. Then given that Syria is nearest equator than Moscow you see there a circle and an ellipse in Moscow.