Data in the Worksheet that are marked as Missing are ignored during analyses. Permanent missing values appear as blank cells and temporary missing values appear in red. You can use the right mouse button to make cells temporarily missing and vice versa.
When importing or exporting files special placeholders (values or symbols) can be used to indicate missing values. These placeholders are specified by the user in the Preferences window, or during file imports by a value or symbol specified in the File Import Properties window. In GS+, the default missing value indicator is the numeric value -99.0.
Missing values appear in output files when a value cannot be interpolated because the location appears in an exclusive polygon or because numerical limitations disallowed its computation (such as when a variogram model is inappropriately used during kriging).