[Qgis-user] coordinate conversion

[Nicolas Cadieux]

Hi, 
That all depends, I guess on what version of WGS 84  datum the software uses to calculate the conversion.   Most softwares don't  even make a difference between wgs 84 and NAD 83.  I would look at the conversion parameters carefully.  Generally speaking, I would go with the governmental product as they must have a better control over stuff like GPS time and Continental drift... 
Nicolas Cadieux M.Sc. 
Les Entreprises Archéotec inc.  
8548, rue Saint-Denis Montréal H2P 2H2 
Téléphone: 514.381.5112  Fax: 514.381.4995 
www.archeotec.ca 
On Nov 12, 2015 13:01, "francesco_lucca [via OSGeo.org]	" <ml-node+s1560n5236051h42 at n6.nabble.com> wrote: 

	Hi,
I have a point in WGS84 UTM32 coordinate
E 589747.816
N 4871699.496
I saved in EPSG 3003 with the following coordinates:
E 1589776.553
N 4871716.117
A colleague made the same conversion using free software "traspunto" ( http://www.mondogis.com/traspunto.html ) developed by the Italian Enviromental Ministry. He got this result (EPSG 3003 coordinates):
E 1589776.054
N 4871716.382
I try another online tool ( http://www.sardegnageoportale.it/webgis/raswebconverter/index?stato_quale=punto ) and I found these EPSG3003 coordinates:
E 1589776.554
N 4871716.119
Summary: QGIS and sardegnageoportale seem to give the same results, traspunto is different (0.50 meter difference). Which is the correct result? Where can I found the calculation for the conversion from a system to another?
Thanks
Francesco 

	
	
	
	
	
	
	
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