Create a classed post map in Surfer

A classed post map is a map where symbols are posted at specific XY point locations, and the symbols are divided into bins by a third numeric value. Each bin has its own specific symbol properties. For example, you could have all points with a low concentration value colored blue square, all points with a medium concentration value a green triangle, and all points with a high concentration value a red circle.

To create a classed post map:

1. Create a data file with X, Y and Z columns. The Z column is the column that is used to class the points. It must be numeric.
2. In the Surfer plot window, click Home | New Map | Post | Classed Post.
3. Select the data file and click Open.
4. In the Contents window, select the Classed Post layer, and in the Properties window click the General tab.
5. Verify the X coordinates, Y coordinates and Z coordinates columns are specified correctly.
6. To edit the properties for each class (numeric range and symbol properties), click the Classes tab in the Properties window and click the Edit Classes button.
7. There are many options to set the class properties (e.g. double click on a specific symbol to edit only that symbol’s properties, or click on the Symbol button to set global symbol properties or specific a color gradient for the symbols).
8. When finished editing, click OK to apply the changes. 

Use classed post maps to divide symbols into classes by a numeric value, and apply specific drawing properties for each class.

Updated September 4, 2020