Greetings. I wonder if you can corroborate my observation that the Yahoo imagery over at least part of Christchurch is "off" by 10m or more.
This means that mapping from GPS traces comes into conflict with mapping that has been done off the imagery. I envisage an unholy mess...
If you care to discuss in more detail: firstname.lastname@example.org --EliotB 09:14, 3 March 2009 (UTC)