The waist is measured from side seam to side seam across the front of the waistline.  Double to get the circumference.   Hips are measured from side seam to side seam across the front  where the hips are on the pant.  Double to get the circumference.  The length is measured from the waistband straight down to the hem. The inseam is measured from the crotch seam straight down to the hem.  
  1 is a small/medium, 2 is a large/x-large.  3 is an XL/XXL
 
1:Waist is 13" (26" around) and will stretch to 23" (46" around).  Hips are 22 (44" around), Length is 33.5", inseam is 23" 
2: Waist is 14" (28" around) and will stretch to 26 " (52" arou