[Proj] Are they six of one...

Roger Oberholtzer roger at opq.se
Tue Apr 7 04:37:11 EST 2009

I am calculating northings/eastings in SWEREF99 TM, from WGS84
lat/longs. I see that I can specify the calculation in two ways:

"+proj=utm +zone=33 +ellps=GRS80
	+towgs84=0,0,0,0,0,0,0 +no_defs"

"+proj=tmerc +ellps=GRS80 +k=0.9996 +x_0=500000 +y_0=0
	+lon_0=15.0  +lat_0=0.0
	+towgs84=0,0,0,0,0,0,0 +no_defs"

and I get identical results. So I am wondering if either specification
has merit over the other. If no difference in results, could there be
any possible difference in calculation speed? Or any other non-religious
reason to choose one over the other? 

Roger Oberholtzer

OPQ Systems / Ramböll RST

Ramböll Sverige AB
Krukmakargatan 21
P.O. Box 17009
SE-104 62 Stockholm, Sweden

Office: Int +46 8-615 60 20
Mobile: Int +46 70-815 1696

More information about the Proj mailing list