function get_center(coords){
const xy = coords.reduce((a,c) => {
if (a[0]===null || c[0] < a[0]) a[0] = c[0];
if (a[1]===null || c[1] < a[1]) a[1] = c[1];
if (a[2]===null || c[0] > a[2]) a[2] = c[0];
if (a[3]===null || c[1] > a[3]) a[3] = c[1];
return a;
},
[null,null,null,null]);
console.log(xy);
const width = get_distance(xy[0],xy[1],xy[2],xy[1]);
const height = get_distance(xy[0],xy[1],xy[0],xy[3]);
return [xy[0] + (width / 2), xy[1] + (height / 2)];
}