Parent Command
all third-level commands in block > OBSERVATION

Subcommand
-

Description
This command reads a list of observation times and the corresponding data. Each list will be referred to as a data set in the iTOUGH2 output file. An annotation is generated for each data set, or a string can be supplied by the user for its identification (see command >>>> ANNOTATION). Data can be supplied either directly following the command line or on a separate file (use keyword FILE followed by the name of the data file after a colon). Time and data must be arranged in columns. They are read in free format. Data are accepted until a FORTRAN input error occurs. The total number of data points read by iTOUGH2 is printed to the iTOUGH2 output file and should be checked for consistency. By default, the first column is expected to hold the observation times, and the second column the data values. Deviations from this format are possible (see commands >>>> COLUMN, >>>> FORMAT, >>>> SET (o), and >>>> HEADER for details). Data can also be represented by a polynomal or a user-specified function (see commands >>>> POLYNOM and >>>> USER, respectively). Observation times do not need to coincide with the calibration times defined by command >> TIME (o). Linear interpolation is performed for calibration times that fall between observation times. This requires, however, that the first observation time is earlier than the first calibration time, and that the last observation time is later than the last calibration time. If this condition is not met, command >>>> WINDOW should be used. Only one time window can be specified for each data set, i.e., multiple data sets must be provided if multiple time windows are needed. If time is not given in seconds, the appropriate time unit (MINUTE, HOUR, DAY, WEEK, MONTH, YEAR) must be specified on the command line. If the units of the data points are different from the standard units used in TOUGH2, a conversion factor must be provided through command >>>> FACTOR.
If no observed data are available (e.g., when performing design calculations prior to testing, or when using iTOUGH2 for generating time series plots), command >>>> NO DATA can be used. In this case, even though the computed results are shown in the residual analysis, the residuals do not contribute to the objective function.
If all actual or virtual data values are zero, command >>>> ZERO DATA can be used.

Example
> OBSERVATION
>> GAS PRESSURE
>>> in ELEMENT: A1__1
>>>> DATA follow in default format, time (sec) vs. pressure (Pa)
01.0 100000.0
10.0 101343.8
20.0 105991.3
30.0 108965.9
60.0 115003.8
.... ........
3600 218762.0
>>>> standard DEVIATION: 5000.0 Pa
<<<<
<<<

>> LIQUID FLOW rate
>>> CONNECTION B1__1 B1__2
>>>> HEADER contains : 3 lines to be skipped
>>>> time and value are in COLUMNS: 3 6
>>>> conversion FACTOR is : -1.6667E-5 [ml/min] to [-kg/sec]
>>>> use SET No. : 3
>>>> DATA are provided on FILE : flow.dat with time in MINUTES
>>>> a RELATIVE measurement error of : 5.0 % is assumed
<<<<
<<<

>> BRINE CONCENTRATION in LIQUID PHASE
>>> ELEMENT: C1__1
>>>> NO DATA available or needed, just for plotting
<<<<
<<<
<<

See Also
>>>> ANNOTATION | >>>> COLUMN | >>>> FACTOR (o) | >>>> FORMAT | >>>> HEADER | >>>> PICK | >>>> POLYNOM | >>>> SET (o) | >>>> USER | >>>> WINDOW