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Home > 8 Data Compensation
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8 Data Compensation
Click the Data Compensation tab to open the Data Compensation Wizard.
In the first step of the wizard, check the Levelogger data file(s) you would like to compensate. Any files you have open in the Data Control tab will be on the list and checked off.
Use the directory on the left of the window or click  to select any other Levelogger data files you would like to compensate, and ensure they are checked off. Select Next to continue.
Figure 8-1 Data Compensation Wizard - Step 1
(Click image to enlarge to full size)
There are eight Data Compensation options available: Barometric Compensation, Manual Data Adjustment, Unit Conversion, Offset, Altitude, Density Adjustment, Barometric Efficiency, and Conductivity Conversion. However, only the options available for your opened Levelogger file type will be active (e.g. Conductivity Conversion is only available for LTC Levelogger Junior files).
In this step, check the type(s) of compensation(s) you want to perform. Note, if multiple Levelogger files have been checked off in the first step, Barometric Compensation will be the only option available. All other options are only available when a single Levelogger file is selected for compensation.
Figure 8-2 Data Compensation Wizard - Step 2
(Click image to enlarge to full size)
Barometric Compensation simply subtracts the barometric reading from the corresponding Levelogger reading(s). If there is an inconsistency of the time stamp between the Barometric file and the Levelogger file(s), a linear approximation on the barometric data will be performed, or an error may occur.
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Manual Data Adjustment allows you to enter a manual water level measurement as a Datum Reference or field zero, which all Levelogger water level readings can then be adjusted to.
If the Datum is above water level (e.g. top of well casing), the datum must be input as a negative value. If the Datum is below water level (e.g. sea level), a positive value is input. The date and time of measurement of the Datum Reference must be recorded to complete the adjustment. This Reference Time must replace an actual reading in the Levelogger file, and is selected from the drop-down menu showing all time stamps in the Levelogger file.
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You can make multiple adjustments to one data file by selecting 'Add' to enter another Datum Reference. All readings after this Reference Time, will be adjusted to this second Datum reference point. You can add as many adjustments to one Levelogger data file as you would like (as long as it doesn't exceed the total number of readings in that file).
Figure 8-4 Manual Data Adjustment
(Click image to enlarge to full size)
Unit Conversion allows you to convert water level readings in a Levelogger file to different units (m, cm, ft, kPa, bar, or psi), or temperature readings to ºC or ºF.
Offset allows you to enter any value, positive or negative, which will be added to each reading in the selected Levelogger file to offset by that amount.
Altitude is used to correct for elevation. Water column equivalent pressure decreases with altitude at a ratio of approximately 1.21/1000 in the lower atmosphere below 5000 m. You can compensate for this by entering an elevation between -1000 ft below sea level and 16,400 ft (or -300 m and 5000 m) above sea level.
Density Adjustment corrects the range of the level channel in the data file based on a user input adjustment of fluid density. The range of the density adjustment is from 0.9 kg/L to 1.1 kg/L.
Barometric Efficiency Adjustment is used to proportionally adjust Barologger data in relation to a particular Levelogger. Barometric efficiency is often expressed as a percentage or proportion. The input field is proportional and has a default value of 1.00. For more information about Barometric Efficiency, see Section 10.1.3. The barometric efficiency can be set from 0.01 to 3.00.
Conductivity Conversion allows you to convert raw Conductivity readings from an LTC Levelogger Junior, to Specific Conductivity (conductivity that is temperature compensated to the standard of 25ºC). The Temperature Coefficient default for Specific Conductivity is 2.00. The Temperature Coefficient should not be adjusted, unless you know the value specific to the solution you are measuring. You can also convert Conductivity readings to Salinity values.
After you have selected the desired compensation(s), click next to select the Barologger file you want to use for Barometric Compensation, or if Barometric Compensation was not selected, click Finish or Finish and Open to complete the selected compensation(s).
If you selected Barometric Compensation in Step 2, the third step will be to select the Barometric file you want to use to compensate the selected Levelogger files. Click Finish or Finish and Open to complete the compensation(s).
Figure 8-5 Data Compensation Wizard - Step 3
(Click image to enlarge to full size)
The compensated data will be saved in a new *.xle file. The default file name will be the <original Levelogger file name> with the word <compensated> added to the file name prefix. Alternatively, the user can name the compensated file. Do not change or delete the file extension. The compensated file can be opened from the Data Control tab, or if Finish and Open is selected, then the compensated file will automatically open in the Data Control tab. All data files are saved to the default location:
<C:\Program Files\Solinst\Levelogger 4_0\Data>.
Figure 8-6 Viewing Compensated Data
(Click image to enlarge to full size)
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