"Summit flattening" in Google Earth
Google Earth (“GE”) is a wonderful tool for trip planning. However, there's a rather annoying bug for alpine climbers - mountain tops that are especially pointy can sometimes appear much flatter than they are in real life. This can make a technically difficult summit appear to be just a casual walk up, which could obviously get you in trouble if that's the only navigation tool you’re using. Let's look at an example.
Here is a photo of Mt. Thielsen in southern Oregon, a popular route. This view, from the Pacific Crest Trail, clearly shows the dramatic and steeply pointed summit block. (The route goes up the right skyline.)
image: Wikipedia, By Claytontullos - Own work, CC BY-SA 4.0
And, here's what the summit block looks like close up.
Definitely not a casual walk up. Most people use ropes and rappel. What’s not shown is the thousand or so foot drop just behind the guy in the red shirt.
image: adamschneider, https://www.oregonhikers.org/forum/viewtopic.php?t=16436
Here's a topographic map that shows the true steepness.
image: Caltopo, US Forest Service 2013, 25% shaded relief
Let's compare that with a few screen grabs from Google Earth of Mt. Thielsen.
Wait, what happened to the pointy summit? Looks like a casual stroll to the top!
More of a close-up . . .
Here’s a view from the increasingly-excellent-if-slightly-expensive mapping software Fatmap. Fatmap uses a different 3D terrain model than Google Earth, and the summit appears much as it does in real life.
image: fatmap
However, Google Earth doesn’t “flatten” every pointy peak. Here's a final example, the iconic Matterhorn Near Zermatt, Switzerland - looks perfect!
So, a good rule of thumb: If you’re climbing something steep but it doesn't look that way on Google Earth, always check other photos and topographic maps to make sure you have a true understanding of the terrain.
