Gridding Methods

Contours are generated by interpolating data point values onto a regularized system of grid nodes or cells. We have already discussed how to increase or decrease the number of cells within our grid. This section deals with HOW the data is interpolated to these grid cells and the methods available to you for doing so.

The current gridding methods within DISurf include Inverse Distance,

Kriging,

Block Kriging,

Minimum Curvature, 

System of linear equations,

Fast System of Linear Equations

and Triangulation.

Minimum Curvature and Kriging methods are more computationally intensive and should be used sparingly for datasets with over 50 data points.

You may choose your gridding method in the 1. Objects | Gridding Methods dialog; 2. in the drop-down menu on the toolbar; or 3. by right clicking Grid in the Map Tree and selecting Gridding Method. If you select option 1 or 3, you may change te default gridding parameters IF the gridding method has an Option or Solver dialogue box. Play with the different options and inputs to see how it changes the map.

If a border or boundary value is assigned, the gridding will asume the set values along the border or boundary, AND the contours will be closed. By default, contours terminate at the border.

To save the grid and its values to a file for export to other applications, select File | Save numerical data command which will write the results to a .txt file.