This article contains written instructions on how to use the measure tool on the iPad to figure out the length of a fence or the outline of a field, as well as the internal area of any shape you draw.
Straight line measure
From the maps page, tap on the lightning bolt shortcut icon
Select Measure
Choose the option Straight line
Tap at the start of the line you want to measure and hold your finger down
Drag to the end of the line and then release your finger
The line will calculate the length as you drag
Tap Done when you're finished
Exact trace
From the maps page, tap on the lightning bolt shortcut icon
Select Measure
Choose the option Exact trace
Drag your finger around the length you'd like to measure (e.g. a fence line, or driveway)
The line will calculate the length as you drag
Tap Done when you're finished
Area
From the maps page, tap on the lightning bolt shortcut icon
Select Measure
Choose the option Area
Outline the area you'd like to calculate
The area will calculate when you join the end of your line back to the start of your line, or, if you lift your finger off the screen
Tap Done when you're finished