Originally posted by CharlieM
Originally posted by Rustler
Google Earth doesn't deal with tunnels correctly. Maybe they will get the problem fixed in the future. In the meantime we'll just ignore grades shown in tunnels. |
Russ,
You broke the code on Eisenhower tunnel. I see that now. However, try the Lee Vining, CA to Yosemite National Park route. This traverses Tioga Pass to the park entrance. GE shows the max slope as 25%. There is a little wiggle in the plot that does show 25%, but I've climbed that road and the max incline in that area is 9%. No tunnels, but there may be some fill. I guess you take Google Earth with a grain of salt, or a big chunk of rock , but it is fun to play with it. Thanks for the tip.
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Yeah, Google Earth elevation profile is a work in progress. I suspect the very short sections of excessive grade (the little wiggles) are due to errors in the ground elevation at different points along the route. Yes, maybe it has to do with the road cuts and fills. When I run a route from Coos Bay, Oregon to Mount Shasta City, California, it doesn't show any obviously erroneous grades. So the results will of course vary with the particulars. But it is kinda fun to play with.
I've noticed another strange thing. Sometimes the close up view of a bridge shows the roadway surface of the bridge laying on the river-bed below. Yes, a work in progress.