[Proj] Lat-Long to Lambert Conformal Conic(2SP) transformation
inaccuracy issue
Tonu Lukk
tonu.lukk at neti.ee
Sun Feb 18 05:31:25 EST 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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