all third-level commands in block > OBSERVATION
If multiple elements or connections are provided to indicate the location of a measurement point, iTOUGH2 takes the average of all calculated values as the model output to be compared to the data. The user must ensure that the averaging of the quantity is meaningful. If keyword VOLUME is present on the command line, the calculated values are weighted by the grid block volume.
>> GAS CONTENT
>>> ELEMENTS: A1__1 A1__2 A1__3 A1__4 B1__1 B1__2 B1__3 B1__4 &
C1__1 C1__2 C1__3 C1__4 D1__1 +3
>>>> ANNOTATION: Ave. Gas Content
>>>> Take VOLUME AVERAGE
>>>> NO DATA