It is possible to grid collinear data in Surfer 15 and newer.  If you are receiving this message using Surfer 15 or a newer version, try using one of the following gridding methods:

• Inverse Distance
• Nearest Neighbor
• Moving Average
• Data Metrics

Surfer 14 and older versions cannot grid data if all of the points are collinear (all in a straight line). 

To work around this in older versions, either add more data points not in the line, or change one of the values by a small amount (e.g. 0.001), save the changes, and grid the data.

Updated November, 2019