Measuring the Waist to Ground Length correctly is crucial for several things. Most obviously, it’s used for making skirts that fall fully to the ground. It’s also the measurement I rely on for estimating fabric use in historical work, as the vast majority of the fabric is in the skirts.
The Waist to Ground Length is measured from the Waist to the ground, running smoothly over the curve of the body to the widest point (at the Full Hip or High Hip, depending on your figure type). Stand in a normal, straight posture with weight evenly distributed over both feet. If you are making an outfit designed to be worn with specific footwear, or hemming a bridal/formal gown, the person being measured must be wearing the exact same shoes they plan to wear to the event. (I’ve seen brides show up for alterations with flip-flops instead of their formal shoes. Shoes should be considered a foundation garment for all fitting purposes.) At the widest point of the body, allow the measuring tape to hang to the ground. The Waist to Ground Length should be taken at the Side, Center Front, and Center Back of the body.
Depending on how curled up your tape is, you might need to put a small weight at the end. It’s possible to take this measurement yourself with the aid of a mirror, but it’s very difficult to get an truly accurate measurement.
If you’re working for a period where a padded roll or other major construct (ie, panniers or a wheel farthingale) is used to support the skirts high on the hip, you should take an additional set of Adjusted Waist to Ground Length measurements over the support. That support will be the widest part of the figure, so allow the tape to hang straight from the edge.
If you’re working in a period where the waist has been moved significantly north of it’s normal position (ie, Jacobean or Empire periods), you should take an additional set of Adjusted Waist to Ground Length measurements from the position of the fashionable waist for the time period (over any needed pads and with the correct foundation garments). These should run from the fasionable waist to the widest part of the figure, then hang straight to the ground. Do not attempt to follow the curve of the body between the fashionable waist and the widest area closely, as the fabric of your finished skirts will not.
If your legs are genuinely different lengths and you do not use a corrective lift, or your pelvis is permanently tilted due to Scoliosis or a similar issue, you should take the waist to ground measurement at both sides of the body.