Tuesday, 6 January 2009

Google Earth Vs the Real World

If you're driving along the A55 in North Wales, a mile or so after passing Holywell, the road curves left and starts to descend through a cutting. As you travel along this stretch of road, the view opens out into an extraordinarily beautiful expanding vista that takes in the Vale of Clywyd and the mountains of Snowdonia beyond.

We drove this way a few weeks ago when we went to Llandudno, and took the opportunity to take some pictures of the view.

This gave me the opportunity to find the same viewpoint on GE, and do a bit of comparing and contrasting.

Firstly, here's what you see on Google Earth...

And here's what you see through the lens of a camera while driving along the real road from roughly the same point...

First thing to note of course is that GE generally avoids adding man made features to its altitude matrix, so as far as it's concerned, the road goes over the top, and not through a groove that people cut into the surface of the planet. Secondly, the scale of distant objects, in this case the Snowdonian mountains, isn't perfect. In real life there is a smooth, analogue recession fading into distance. In GE it pops a small but perfectly clear feature into the distance. Obviously, the road in the first image is in extreme close-up by GE standards, and so is rather pixellated. I've noticed that the resolution available varies from place to place. It's not just the difference between satellite and aerial photography. One way of seeing this is to look at the point at which cars become pixellated. I will be doing a seperate post about this soon.

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