To officially launch this blog (I've been happily talking to myself here so far) I've published a podcast about using lines in Google Earth projects:
here's the related Google Earth .kmz file
Its a development of another podcast I did a while back at my podcast site Kokae on more general design:
If you care to watch both you will spot a contradiction. In the first 'Lines' podcast I extol the virtues of the sludgy coloured line and then in the second I go and use lots of brightly coloured lines. I would argue that I'm sticking to my own rules, in the first case using a grey line produced a map that had lots of data on it. In the second there was less data (positions of ships and their routes) but more types of data (different voyages). Differentiating between the routes became more important than being able to see lots of data in one go.
Part of the problem lies in Google Earth, when you view a Google Earth project data is plotted on top of satellite imagery which allows a user to see where they are. In a traditional map the background would be white, the user has to scratch her head to work out where the map is and which way its pointing *but* subtle differences in icons or lines stands out more clearly. All of which gives me an excuse to dig out a historical map of Hawaii from the David Rumsey collection:
It doesn't use colour but you can imagine if we plotted Cook's journeys around the islands we wouldn't have to resort to bright, primary colours lines to do so.
Aside: The Hawaiian chain was initially known as the Sandwich Islands as marked on the map and Hawaii, correctly pronounced Ha - vai - ee was spelt a decidedly odd 'Owyhee'.