[OSM-newbies] GPS inaccuracy

[David Read]

Dear all,

I did my first track last night using my GPS and was surprised to see the trace wandering far from the road I was supposed to be on. See the yellow line here:
http://tinypic.com/view.php?pic=25q662s&s=5
I was cycling in a pretty straight line down the road I can assure you! Yet the line goes up to 20m either side of the map line.

Anyway, I did this with my Nokia 95 and WhereAmI+ software (will try Sports Tracker next too), but this wild result doesn't seem good enough to do mapping with. 

Is this because I have a rubbish GPS receiver or could it be that the buildings of Islington are causing sufficient reflection/disturbance to the signal?

David