[Proj] Cosmetic latitudes, and the diacritics of Josef Krovak and others

[strebe at aol.com]

daan wrote (about a central latitude that doesn't affect the shape of the 
projection): 

> Snyder includes it explicitly in his formulations, referring 
> to it as the "latitude of origin" and denoting it as φ₀.

Yes, now that you mention it. I have never noticed it before, but Snyder 
uses phi_0 when the parameter does not affect the projection shape, but 
otherwise he uses phi_1 (which he often calls the "latitude of the center of 
the projection and origin"), or else phi_1 and phi_2 for two standard parallels.  

This convention is, in fact, stated in his list of symbols on pages viii - ix, 
which I hadn't read carefully enough before.  

"Latitude of origin" sounds fine, but I am not too fond of using 
many different names for what is called lat_0 in Proj.4.  The 
EPSG Guidance Note 7.2 has gone too far in this direction, I think. 
I like "central latitude" as the only name.



 


 

Please note also that "Latitude of origin" is the  name in the Well Known Text format specification.
E.g.,

PARAMETER["latitude_of_origin",49],


Regards,
— daan Strebe


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.maptools.org/pipermail/proj/attachments/20090323/759ce1a4/attachment.htm