Surfer's data filter allow you to filter data by X, Y, and Z variables as well as any column in the worksheet containing numeric data.
The Filter dialog accessed by clicking Filter in the Grid Data dialog
To filter data by a worksheet column during gridding, follow the steps below.
- Click Home | Grid Data | Grid Data.
- On the Select Data page of the dialog, click Browse, select your data file and click Open.
- Assign the X, Y, and Z columns and then click Filter Data.
- In the Filter dialog, enter the desired expression such as _E = -999. Where E is the desired worksheet column. The underscore differentiates worksheet columns from standard X, Y, or Z variables.
- Click OK.
- In the Grid Data dialog, set the gridding parameters as desired.
- If desired, click Statistics to verify the filter is applied as desired.
- Click Finish on the Output page to create the grid file.
The same filters can be applied in the worksheet using the Data | Data | Spatial Filter command or when creating a variogram using the Grids | New Grid | Variogram | New Variogram command.
- How can I enter a "null value" (a value to be ignored) when gridding or doing a transform on the data in Surfer?
- Surfer Help | Data Filters
- In Surfer's Gridding Report, why aren't all of the deleted and retained duplicates reported under Duplicate Filtering?
Updated November 2021