Is a straight line on Google Earth or Google Maps geodesic?

Question

Is it a straight line on a geological map of Google or Google Maps? That is, when I look at Google Earth or google maps data on my 2nd computer screen, is this an image that I see “correctly configured” correctly, that the straight line in this “adjusted” image is actually geodesic?

If this is not the case, are there any options that I can choose in these applications that will allow me to “adjust” the image so that the straight line on this “adjusted” image is geodesic?

Are there any other free applications that display "adjusted" maps, where the straight lines on the screen are actually geodesic?

Are there any free applications that will provide me with a geodesic path between two points on the earth?

Thanks in advance.

Answer 1

First of all, it is clear that the lines are not ellipsoidal geodesics. For example, the line between (lat, lon) 0,0 and 0,179.99 in Google Earth is shown along the equator instead of a shorter path going near the pole.

The KML documentation says that the sides of the path are "great circles," and that the sides of the polygon are "lines of constant support." I believe that the “great circles” become great ellipses (a path along an ellipse whose center is the center of the Earth). The usual understanding of "permanent bearing lines" is that they are the lines of the lines, i.e. that they correspond to straight lines on the Mercator projection. However, the documentation lies. Instead, there are straight lines in the projection of the plate.

I asked Google to use surveying for both kinds of objects, and they are considering this.

I wrote the C ++ library GeographicLib , which solves the geodesic problem. If you want to see how to create a sequence of points along a survey line, see the example in the documentation for the GeodesicLine class . If you just want to test the solutions, check out the online survey calculator .