The distances in a straight line service calculates the distance in a straight line between two or more points, by taking into consideration the curvature of the earth. This service provides also an estimation of the flight time between the points chosen.
Note: The driving distance between the points differs from the result you will get via this service. For the distances in a straight line service, you can find instructions as well as expamples of usage below.

Km
Miles Nautical Miles 
Usage of buttons on the right side
User instructions
Distance calculation between 2 points in a straight line
In the example below, it can be seen that the straight line distance between Athens and Volos is 168,3 klm.
Distance calculation between multiple points
If we proceed in roughly comprising the driving distance between Athens and Volos, then we get a total distance of 301,1 klm.
For a much more accurate calculation of driving distances, we recommend you use the apostaseis.gr driving distance service.
Distance calculation taking into consideration earth's curvature
The straight line distance calculation service always takes into consideration the curvature of the earth, therefore for example, you can see the route which an airplane follows to cover the distance Athens  San Francisco, where the total straight line distance is 10935 klm.
Flight time calculation
The current service is also providing an estimation for the flight time required to cover a selected distance. In the previous example of the Athens  San Francisco distance, you will notice that the flight duration is roughly 12 hours and 40 minutes.
Local distances calculation
In a local level you can also measure how much for instance your house is located vs a point of interest, e.g. the distance of the Athens College track shown below, is 400 meters (0.4 klm).