Measure Change
Your everyday tape-measure measures the distance between points, the WatrLevel measures the vertical change between points.
With the WatrLevel you first select a reference point, this is the point that all subsequent measurements are going to be compared too. For example, figure 1 shows 5 points (A - E), any one of these points can be chosen as the reference point. For this example we will choose point C. The WatrLevel will instantly tell us that A is 5" higher than C, D is 3" lower than C, B is 3" higher than C, and E is 9" higher than C.
The distance between
the points is unlimited (although once you exceed the length of the tubing
you will need to reset). In addition, you do not need line-of-sight
to perform these measurements.
figure 1
Another example (figure 2): here the WatrLevel will measure the vertical change between F and G. If the straight line distance between the two point is known, then the slope can easily be calculated. If there is no vertical change between the two points then they are level.
The WatrLevel is often used to determine if 2 (or more) points are level, and if they're not, the WatrLevel will instantly read how much out-of-level the 2 points are.
figure 2