Logarithmically distributed data does not display clearly on linear axes. While there is not a direct way to apply logarithmic scaling to axes in Surfer, the same appearance can still be achieved. To have the X or Y axis in logarithmic scale, take the log of the original data in the Surfer worksheet and regrid the data.
To calculate the log of the data in Surfer's worksheet:
- Click File | Open and open the data file in the Surfer worksheet.
- Click Data | Data | Transform.
- If the data you want to be log is in column A, and column D is the empty column where you want to store the log values, enter the Transform equation: D = log10(A). This will calculate the log base 10 of the values in column A and enter them into column D.
- Click File | Save and File | Close to save and close the data file.
- Click Grids | New Grid | Grid Data, select the data file and click Open.
- Choose your gridding parameters, selecting column D as the X or Y data column instead of column A.
- Click OK and the new grid is created. Create a map of this data. The axes will still be linearly scaled, but the values will be the log values.
To illustrate that the data is logarithmic, a prefix of "10^" can be added to each label by completing the steps below.
- In the Contents window, click the Bottom Axis (X) or Left Axis (Y) to select it.
- Click the Labels tab in the Properties window.
- Expand the Label Format section.
- Enter 10^ in the Prefix field.
If you would like to see true logarithmic axes as a feature in Surfer, please let us know by emailing firstname.lastname@example.org.
Updated October 23, 2018