Measurements can be made up of multiple Paths. Each Path is just a way of viewing the connections between points. You can change Pathtype while you measure or after your measurement is complete.
Straight Line is the most common path type you will use and the default when measuring. This simply connects each pause point with a straight line.
Trace Lines will show you the precise movement you made as a curved line between the pause points.
Circle mode will display the best fit circle that goes through as many of the points you measured as possible.
Arc paths will show the best fit Arc for all the points in the path.
Ignore Lines is a special type of Path. The points in this Path will be ignored and won't be captured in your measurement. You can use this path if you need to walk a long distance that you don't want recorded. Remember to pause often as you measure, to improve accuracy.