Changing the distance interval will clear results on the screen from previous analyses calculated with a different step. Results based on the new step must be re-generated with Calculate command. Note also that changing the distance interval on the Semivariance Window will also change the distance interval on the Moran's I Analysis Window and on the Fractal Analysis Window, and vice versa. Anisotropic Axis Orientation Anisotropy refers to a direction-dependent trend in the data. Anisotropic analysis allows you to see if your data have a directional component that might arise from a variety of unforeseen factors.
Anisotropic analysis is irrelevant for single-dimension data such as a transect or a time series.
The map is accessed by pressing the Surface command at the bottom of the Semivariance Analysis window. The Principal Axis is the direction of maximum spatial continuity, or base axis from which the offset angles for anisotropic analyses are calculated. The axis orientation should correspond to the axis of maximum spatial continuity, i.e. the major anisotropic axis . In anisotropic analyses, the Offset Tolerance determines how closely the alignment between any two points needs to be for those points to be included in the analysis for a given offset angle. Two points will be included in the analysis for a given offset angle if the angle between them is within the offset tolerance from the offset angle.