We want to build a coherent representation of geographical time-space. In such a representation the measurements of length, which I introduced as measurements of the* visual length*, must be proportional to time-distances. A simple way to check this property of the representation lies in the direct measurement by means of a ruler on the computer screen!

And the measurement shown that the ratio of the length of long and short routes, here around 2.3 is not consistent with the ratio of speed which is 7.5 when confronting a terrestrial speed of 100 km/h with the mean long haul airline speed of 750 km/h. We still have to work!