Geodesic calculations for an ellipsoid done right (original) (raw)

Find the perimeter and area of a polygon whose sides are geodesics. The polygon must be simple (i.e., must not intersect itself). (There's no need to ensure that the polygon is closed.) Counter-clockwise traversal of the polygon results in a positive area. The polygon can encircle one or both poles. The sample gives the approximate perimeter (in m) and area (in m2) of Antarctica. (For this example, Google Earth Pro returns an area which is 30 times too large! However this is a little unfair, since Google Earth has no concept of polygons which encircle a pole.) If the polyline option is selected then just the length of the line joining the points is returned. To perform the calculation, press the “COMPUTE” button.

Enter points, one per line, as “lat lon”:

points (lat lon):

Treat points as: polygon polyline

status:

number perimeter area: