[Proj] LA addenda

[Michael Ossipoff]

Linear approximate is a function whose input is a cylindrical or 
pseudocylindrical map that is conformal or equal-area, and whose output is a 
linear cylindrical or pseudocylindrical map that approaches the input map as 
a limit, as the latitude zones become smaller and more numerous.

The definition that I've given, and the specification of the input map's 
shape--its borders--, and whether it is equal-area or conformal, defines a 
particular LA map.

Michael Ossipoff