Scans -> scan-level coordinate frames. Each scan maintains its own scan-level coordinate 
frames based on the scanner it was scanned with.

Slide-level coordinate frame (common, agreed-upon frame of reference for a slide).

<img src="resources/slide_axes.png" width="100%"
alt="Picture of the slide coordinate system, which assumes a slide placed horizontally
with the label on the left. The x-axis points to the right, and the y-axis points
down. The origin is at the top left corner. Key positions, such as the origin of the
slide's active area at (14500, 2500) micrometers and the bottom-right corner at
(72500, 22500) micrometers are displayed." />
