[Proj] Lat-Long to Lambert Conformal Conic(2SP) transformation inaccuracy issue

Tonu Lukk tonu.lukk at neti.ee
Sun Feb 18 02:31:25 PST 2007


Thanks for the reply. First a correction - in my original posting the  
backslashes were removed from the command line. They were actually present  
when I ran the tests. My mistake.
It does seem to be a windows' shell problem but I can't really figure out  
what exactly is causing it.

Two tests.
1.
proj +proj=lcc +lat_1=58N +lat_2=59.333333N +lat_0=57.517553N +lon_0=24E  
+x_0=500000 +y_0=6375000 +ellps=WGS84

Input 24E 57d31'3.19415"N gives	500000.00       6375000.10
Input 24E 57.517553N      gives     500000.00       6375000.00
This hints that the problem lies in the command line parameters - as far  
as I understand the difference in conversion is most likely caused by  
rounding accuracy of an input value.

2.
proj +proj=lcc +lat_1=58N +lat_2=59d20\'N +lat_0=57d31\'03.19415\"N  
+lon_0=24E +x_0=500000 +y_0=6375000 +ellps=WGS84

Input 24E 57d31'3.19415"N gives 500000.00       6375098.83
Input 24E 57.517553N      gives 500000.00       6375098.72
Obviously the problem is in command line parameters. Further testing  
showed that it (in my case) is caused by the +lat_0=57d31\'03.19415\"N  
parameter. Also tried with \" removed from the end, but with the same  
results. Somehow it is interpreted wrong.
Any ideas why?

Tonu






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