Guys, I need help – What is the greatest distance inside this map? – February 24, 2023 at 02:16PM

Going directly to the subject: I need to find what is the greatest distance there is inside my country (Portugal). It is not simply the nothernmost-southernmost or westernmost-easternmost points distance, it is some other distance between two points on the border.

Important: the distance I’m talking about is the arc of a great circle (kind of the analog to a straight line, but on a sphere).

There is a tool to measure distances on google maps, but I can’t determine, with scientific rigor, which are the points from which I should calculate the distance.

One guess is that it is between the easternmost point (41.574831,-6.189158) and somewhere like the point 39.395189,-31.263302. But I guess it could be anywhere else along the borders.

I should highlight that some points like the Ilhéu do Monchique (which is the westernmost point), the Ilhas Selvagens (small islands, islets and reefs that are the southernmost part of Portugal) and even the islet in the east that I suspect it may be one of the points, do not appear before zooming or changing to satellite view or even highlighted as part of Portugal (on google maps, at least).

I don’t know if there is some kind of tool, algorithm, or mathematical law to find this distance, but the problem is very interesting and I would really appreciate and thank who solve that! A mathematical explanation as a bonus is not required at all (I really need the answer), but it would be cool!