Total Length
Measure straight down from the very top of the waist to the hem, along the side seam of the pants.

Waist
Align the front and back of the waist neatly, then measure horizontally from the left end to the right end.

Hip
Mark a point approximately 20cm down from the waistline along the side seam, then measure horizontally from the left end to the right end.

Thigh
Measure horizontally from the left end to the right end, approximately 2.5cm below the lowest point where the inseam seams meet.

Hem
Measure the horizontal length from one end to the other, based on the flat measurement of the very bottom hem of the pants.