Hydrological Services Pty Ltd
Wireless Level Transmitter
©
Copyright
WLT420 100-15
Issue 1.20 5 Dec, 2007
The line drawn on the chart is the 4
th
order polynomial. You should get a good idea of how
well the formula fits the tabled data.
The formula generated in this case is :
Water Volume = 0.8065 x
4
- 18.957 x
3
+ 165.76 x
2
- 19.588 x + 0.000
(where x is the water depth in metres)
For this example, the polynomial terms entered into the WLT420 are as follows :
(Please note the sign of each term !!!!!)
Poly0 = 0.000
( term for x
0
, which is the intercept )
Poly1 = - 19.588
( term for x
1
, which is just x )
Poly2 = 165.760
( term for x
2
)
Poly3 = - 18.957
( term for x
3
)
Poly4 = 0.8065
( term for x
4
)
As the water level now changes between 0.000m and 10.000m the water volume of the
reservoir will be displayed.
The water volume created from this 4
th
order polynomial is
not exact
– but it is a very good
approximation.
