Trend Surfaces

On the Grid / DTM tab, in the Grid Tools group: Click Trend Surfaces to take a Grid Surface file or a Data file as input and generate a Trend Surface based on the data, using a Linear, Quadratic or Cubic equation The Output file will be of the same type as the input file and may contain either the trend surface data or the residual.

The choice of output results depends on whether you want to see the global trend or emphasize local anomalies.

Note that this function does not itself produce a display. In the case of Data file output, you need to use the New Grid function before you will be able to view the results via the Display Layers > Contour option (on the Home tab or the Vizex tab, in the Layer group).

Input file type

Select a (GRID or Micromine Data file type and enter (or double-click to select) a file of that type. If you selected a Microminefile, optionally define a filter to selectively control which records will be processed.

X, Y, Z fields

If you selected a Micromine file, double-click to select the names of the fields containing X, Y and Z coordinates.

Trend surface

Choose the type of Trend surface (LINEAR, QUADRATIC or CUBIC). This determines the order of the equation used for the calculation, and your choice will depend on the source data. The aim is to minimise the variance between the measured points and the trend surface. In general, higher order equations give better results but take longer to calculate.

Output format

Choose the Output format. If you select TREND SURFACE, the output data will represent the calculated trend surface. If you select RESIDUALS, the difference between the original data and the trend surface is written to the output file (to emphasize local variations). Output Types

Output file

Enter or double-click to select the Output file name. Only a file of the same type as the input file can be selected.

Run

Finally. click Run to generate the Output file.