Motion Scanner
You can access your built-in Motion Scanner by pressing the TAB button on your keyboard. This is not an Inventory item, but is part of your built-in Pip-Boy functions. It will show you a mufti-colored top-down view of your Character's immediate area, and will update live for motion adjustments. So if you watch your scanner while running, the scanner shows this as live movement. It has a HI/LOW sensitivity toggle switch and 12 zoom levels that are adjusted with your mouse wheel.
Shown here is a typical Trapper Camp scene with tents that appear as large boxes in the scanner. The upper image is on zoom level 1 with the sensitivity on HI to show ground effects. The lower image shows the same exact scene with the Character standing in exactly the same hex, but on zoom level 5 and sensitivity on LOW. The area closer to the Character is highlighted in a brighter color.
NOTE: This feature not to be confused with a Motion Sensor, which is an Inventory item used to help you see through walls, find people running in Sneak mode, and help detect traps sooner.