Use a Conversion Table

Use a Conversion Table

Conversion tables can also be used to convert data from one form to another. There is no limit to the number of points that can be converted. By default, Calculations uses a linear interpolation to calculate data between points. If data is above or below the values specified in the table the slope of the line is continued and the data calculated.

 

Convert data using a conversion table in Calculations

  1. Ensure the data for conversion is displayed in your datasheet.
  2. Right-click in the datasheet area and select Calculation.
  3. In the Calculation window select the appropriate Level for Master Variable A.
  4. Select a Variable as the Master Variable A.
  5. Check Use Conversion Table.
  6. Select the saved conversion table from the drop-down list or select Use latest table.
  7. (Optional) To view the Conversion Table, click ... next to the dropdown arrow.
  8. Select the type of Spline Interpolation between the selected variable and the conversion table from the Conversion Method drop down combo box.
  • Linear - assumes a straight-line relationship and draws a straight line between the points in the table. Linear is the default setting in the Calculations Tool.
  • Cubic - forms a piecewise continuous curve, passing through each of the known values with a separate cubic polynomial for each interval.
  • Catmull-Ron - a specific cubic spline interpolation, requiring at least two points either side of the differential point.
  • Akima - a special spline which is more stable to outliers than cubic splines.
  1. When completing conversions using a Conversion Table, the Formula entered can simply be A (or lowercase, a).
  2. (Optional) If you want to view the conversion result, click on the Calculation Result
  3. Select the Output Variable that the result will be written to.
  4. Select the Output Level. Mostly, this will be the same Level as the originating data, however you may wish to transfer large volumes of data from one Level to another.
  5. (Optional) Set Flags, if required.
  6. Check Calculation in the Update section to allow resulting data to become available for reiterative calculations with the Calculation tool.
  7. (Optional) Check Database in the Update section to allow data to be written back to the database.
  8. Click Update to finish. Your converted data will be updated.

Notes

When you choose  "Use latest table", Calculations will apply the most recently saved Conversion Table assigned to that Level. Thus, when you combine this setting with Repeat The Calculation For All Levels, the most recently saved Conversion Table for that Level is applied across all Levels founds within the input data set.

In mathematics, a spline is a sufficiently smooth polynomial function that is piecewise-defined, and possesses a high degree of smoothness at the places where the polynomial pieces connect (which are known as knots). Interpolation is to determine a value of y corresponding to some value of x for a set of bivariate data (x, y), at which there is no measurement of y. Spline interpolation if favoured over polynomial interpolation because when the number of data points involved becomes large, in many cases, you can get oscillatory behaviour in the resulting polynomial.

If you choose to use a conversion table during your calculation, then you may not Use Current Flag with your data.

 

Open Regressions tool from the Conversion Table

You can load the current conversion table into the Regressions tool directly from the Conversion Table grouped tab.

  1. Click Conversion Tables from the DataSight Ribbon.
  2. Double-click on the Conversion Table row that you would like to load. A new tab with the Conversion Table opens.
  3. Click Conversion Table grouped tab on the ribbon.
  4. Click Regressions to load your table in the Regressions tool (See Regressions to find out more about this tool).

 

Create Expanded Conversion Table Report from the Conversion Table

You can create an Expanded Conversion Table report of the current conversion table directly from the Conversion Table grouped tab.

  1. Click Conversion Tables from the DataSight Ribbon.
  2. Double-click on the Conversion Table row that you would like to load. A new tab with the Conversion Table opens.
  3. Click Conversion Table grouped tab on the ribbon.
  4. Click Expanded Rating Conversion Table to create the report (See Expanded Conversion Table to find out more about this report).

 

See also:

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