Clarifications on the map scale info box

[CRider]

Hi,
Some pieces of information in the map scale info box are a bit unclear/strange :
(see the attached screenshot)
- the second element : 1:32 306 looks like the map scale
but when the map is just moved, the value changes
- the third element is Ok : 11/13
the 11th map level among the 13 available levels is displayed.
But what is the meaning of the last element (15) ?
Thanks.
Regards.

[Psyberia-Support]

Hi,

Here are more explanations of all these numbers, since it's not explained anywhere else:
- The 1rst number is the real length of the scale. "100m" means that the displayed scale on the map equals 100 real meters.
- The 2nd number is the display scale. For a display scale of "1:10,000", 1cm on the screen is 10,000 real cm, ie 100m.
It's usually close to the given map scale (ie "1:25k" or "1:25,000"), but not exact since it depends on the display zoom.
As you point out, it also depends on the displayed location. The reason is that main maps (including Google, OSM, etc) use the Mercator projection, which scale depends on the latitude. Mercator maps are square, so equal in pixels at all latitudes, whereas it is not the case for the earth perimeter (few meters near the poles and largest at the equator). This can be visualized using the Tissot Indicatrix of the mercator projection available here, circles (representing a given fixed area), increase when going towards poles.
- The 3rd number is the current map level number among total map levels.
- The 4th number is the Google/OSM equivalent zoom value. In your example, the level number 11 has the zoom value of 15 for Google/OSM maps. This number has been requested by users familiar to these zoom value notation.

Best regards

[CRider]

Thanks.
It may be worth copying/pasting this explanation somewhere in the help file.
Regards.