[Proj] Parsing Lambert Conformal Conic in GDAL

Andre Joost andre+joost at nurfuerspam.de
Fri Jan 3 10:49:39 EST 2014

Am 03.01.2014 04:00, schrieb Kyle Shannon:
> Is it okay to set a lat_1=lat_0,
> and also specify lat_2.  I suspect it is, but I haven't found any
> concrete definition on limits (and I don't really think there are,
> within reason).
> Thought I'd consult the pros on the list to be sure.

In the formulas given by Snyder, a single parallel LCC projection is 
defined by lat_1=lat_2, but he makes no special treatment for lat_0 (the 
latitude of origin) is equivalent to lat_1 or lat_2 or not.

Reading older proj trac tickets, I gathered that lat_0=lat_1 is 
misinterpreted in proj4 as lcc single parallel projection. This does not 
coincide with the WKT projection strings supplied by ESRI and others.

André Joost

More information about the Proj mailing list