Issue of losing orientation (Desert fog effect)

This issue can be summarized as not knowing where you are on the canvas while using a zooming user interface. You see a blank screen with not enough clues to know here you are.

Problem

Here the content is out of sight. It can be bigger or smaller than the screen, nothing is visible.

Here the whole content is in that 3x5 pixel blot what you see on the top left.

Solutions

Home Button

As you move your cursor on the screen those navigational buttons on the left appear. Home takes you back to the overview of your content (if you have any).

Minimap

One way of showing your location is an overview map, what shows your location from above. This is typical in computer games.

Visual Clues

Autodesk 3DS Max shows a grid and a clear origo, even if your workspace is empty.

Other solutions

There can be many other solutions to show spatial location and zooming degree. For example breadcrumbs, colors or blurring can help in orienting the user.