Filter data out before performing transform in Surfer

Filtering data is a crucial step in data analysis and management and can be utilized for many things including data quality, compliance, noise reduction, improved visualization. To specify a value to ignore in the Surfer worksheet when using Data | Data | Transform, you can convert the number to a text value. Surfer can ignore any text string (non-numeric values) when performing a transform. 

To convert a number to a text value in the worksheet, follow these steps:

1. Select the column of data that contains the values you want to convert to text.
2. Click Data | Find | Replace.
3. In the Find and Replace dialog, enter the value you want to ignore in the Find field, and in the Replace with field, you can enter either NA, null, or simply enter the number and prefix it with an apostrophe or quotation mark ('999). 
4. Click Replace All. Now the values are converted to text.
   
5. Click Data | Data | Transform.
6. Enter the transform information as desired. (Transform with, Transform equation, First row, Last row)
7. Under the Text cells section, click the drop down and select Are treated as text.
8. Click OK and the transform is applied, ignoring the cells with text in them.
   

Additional resources

• Surfer Help > Transform - Worksheet

Updated January 2024