[Proj] Parsing Lambert Conformal Conic in GDAL

Andre Joost andre+joost at nurfuerspam.de
Fri Jan 3 07:49:39 PST 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.

Greetings,
André Joost




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