Re: Worldmap mercator projection - Latitude to Y calculation.

John,

>> Did you _try_ using just the tangent on a couple of places?
...
> I have to do some more experiments.

After having done so, it looks like that

tan(DegToRad(Latitude)*0.78)\2.53627

gives a nice result.

Though I used 75 degree latitude as the reference for the "will the 
calculated lines overlap the ones on the image?" test, causing all lower 
calculations to be /just/ under the lines on the image.

Re-doing it using 65 degree latitude as a reference should give a better 
result (75 degree just above its target, the others just below their target)

As I mentioned before, good enough to get an indication of the location 
you're looking for, but it can be hundreds of miles to low (or high) ...

By the way, 0.78 is rather close to Pi/4 .  Somehow that raises my suspicion 
that that is the actual value to be used, and my 0.78 is caused by my "that 
looks good" eyeballing ...

Regards,
Rudy Wieser