[Potlatch-dev] Lat vs Latp

[Richard Fairhurst]

Steve Bennett wrote:
> Hi,
>    I was hoping to figure this out for myself but I can't. What's the
> difference between lat and latp? I see a trigonemetric conversion
> function, but what's the purpose?

lat is the raw latitude. latp is projected latitude.

In other words, latp->y co-ordinate is just a simple matter of 
multiplication, just like lon->x co-ordinate (in the Mercator 
projection, at any rate).

If you didn't project it then things would look squished and you 
wouldn't be able to use tile backgrounds.

cheers
Richard