The base model of the view is a single, flat plane (a plain!), with sky above. All buildings and other objects are placed on this plane.
Keyboard
up-arrow ↑ move forward (in the direction the camera is facing)
down-arrow ↓ move backward
left-arrow ← move left
right-arrow → move right
- move down
= move up
q rotate counter-clockwise (look left)
e rotate clockwise (look right)
w move forward (in the direction the camera is facing)
s move backward
a move left
d move right
[delete] ⌫ delete the clicked or selected note
1 reset view: move to a known location
Mouse
click on a building to select it, and to point the camera at it.
click on the ground to deselect the current selection
drag the ground to move the camera, which continues to point in the same direction
drag buildings to reposition them
Trackpad
pinch-zoom to change the focal length of the camera