Doesn't Google Earth do this?

Google Earth^™ is a fantastic tool that we recommend all photographers explore using in their planning. And yes, the desktop native version has included simulation of natural light for some years now.

Here are a few particular things that TPE 3D does, which make it particularly suited to the needs of outdoor and landscape photographers.

• TPE 3D simulates the lighting on your mobile device - you don't need to be at a desktop or laptop
• TPE 3D makes is super easy to control the time of day precisely without accidentally rushing past the key moment
• TPE 3D provides a clear visualization of where the sun, moon and galactic centre are at any time making them very easy to find
• In Enhanced Mode, the app allows you to control the camera zoom to a particular focal length, making TPE 3D useful as a guide to lens selection and composition
• Satellite maps have shadows already baked in, which can make it tricky to interpret what is lighting from the model vs what was actually captured when the photo was taken. Topographic maps don't suffer from that same problem
• If you already use TPE, then you can access the same list of saved locations that you've already built up
• TPE 3D includes lists of daily and annual events, such as twilight times, sunrise, solstices, moon phases, etc. for easy selection 

Google Earth is a trademark of Google Inc.