Thought you may all be interested to know that you can now edit Google maps, much like the Openstreetmap project. I've started adding in much more detail about Portobello and I hope others will join me both to add their own data and to review the changes others have made. So far, I've added Christians path, the Brunstane burn paths, some of the routes up to Asda and various building outlines.
The link you need to get involved is http://www.google.com/mapmaker