[Tagging] Off Topic: alignment point help

Martin Koppenhoefer dieterdreist at gmail.com
Thu Jun 11 07:49:25 UTC 2015



sent from a phone

> Am 11.06.2015 um 00:40 schrieb johnw <johnw at mac.com>:
> 
> Since there is an imagery offset, many mappers over many years have used different offset points, so I don’t know which one is the most correct for this imagery. 
> 
> Would someone who uses JSOM with a proper imagery offset please go in and move these lines to their exact position on the imagery and save the edit, 


offsets are an approximation to reduce the inherent problems of some aerial layers, they won't solve problems like distortions. JOSM isn't more precise to find a "proper offset" than any other tool, I suggest you simply move the layer till it visually seems ok. Unless you do high precision measurements in the field you won't know for sure what is "right" and what is "wrong", or in other words: more or less accurate. IMHO, relative precision (eg alignment, angles, straight vs curves etc) is more important than positional precision.

cheers 
Martin 


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