A few months ago I made the case that we are living in the golden age for hikers and backpackers. One reason: the many ways we can visit the trail and campsites from the comfort of our homes. Here is a partial list of the available applications.
Google Maps (https://www.google.com/maps/). Google maps is probably the first place many hikers will turn. The satellite maps are high resolution and the John Muir Trail is pretty well marked for the entire 211 miles. In many cases the resolution of the photos is such that you can actually see the trail. Wow. Google maps also does a great job of providing vehicular directions to and from trailheads. My only complaint? Sometimes the satellite photos are taken during the winter and all you see is snow. When that happens I usually turn to Bing.
Bing Maps (https://www.bing.com/maps/). Bing maps makes the perfect compliment to Google maps. If one is a tad out-of-date, or shows only snow, try the other. I actually find the interface a little easier with Bing, but that is just a personal preference. Since they buy their photos from a different service the sun may be in a different location at the time of the exposure. That could make a difference when trying to determine what the terrain looks like.
Google Earth Pro (http://www.google.com/earth/download/gep/agree.html). Google Earth Pro is now free. It is an application you can download to your computer, which means it runs faster and is less dependent on a internet connection. It also has the capability to tilt the view in such a way as to see a bird’s eye view in any direction. I find it particularly useful when planning off-trail travel.
Caltopo (http://caltopo.com/). There have been lots of online topographical map websites on the internet for a long time. Caltopo was the one that got me to stop using National Geographic TOPO, which is old software no longer supported or updated.
As an example of each, here are a series of screenshots of a favorite campsite of mine for the second night out of Happy Isles, near Upper Cathedral Lake.
Good hiking, Ray