Does magnetic variation matter when creating a KMZ?

Posted by Pat Macleod on
URL: http://maprun.308.s1.nabble.com/Does-magnetic-variation-matter-when-creating-a-KMZ-tp38.html

To some extent this is somewhat academic here in the UK, with magnetic variation at about -0.6 degrees, and reducing, but I've been wondering whether for purposes of complete accuracy we need to take it into account when generating a KMZ. My very brief experiments suggest that if you are exporting a KMZ from OCAD , OCAD handles it, and the map is accurate in Google Earth. On the other hand if you are going via a JPG and the maprun KMZ utility - eg from Open Orienteering Mapper - then it does matter, and you need to rotate the map to grid North before exporting to JPG. Can anyone elaborate or correct me on this?