Select the zone or sub-zone with which to work. By default, selecting the zone node selects all of the sub-zones beneath that node to which to apply changes. You can select either a single sub-zone or all of the sub-zones within a Zone, but not only some of the sub-zones within a zone. When highlighting is enabled using the View menu, as you select a zone or sub-zone, the boundaries of that zone are highlighted on the depth model (zones in yellow and sub-zones in blue).

For a zone that intersects a well bore, select whether to interpolate the velocity field between wells by first taking a value from the top of the zone and then from the bottom of the zone and grading downwards (Top); or by first taking a value from the bottom of the zone and then from the top of the zone and grading upwards (Bottom). If there isn't sufficient data to interpolate, select Squeeze/Stretch instead.

Type values for a constant impedance field when you don't have wells for an area. To automatically change all zones in the model, click Constant in the Set all pane below.

Select whether to apply a specific lithology to the zone from the drop-down list. Click Edit to display the Edit Lithology dialog box and change the color applied to a lithology throughout this and other models.

Click to apply the options available in the Interpolate Well and Constant areas above to all zones throughout the model.

Select whether to color the zone using the pattern selected in the Lithology drop-down list above. If selected, the coloring won't appear until you select a different zone or close this dialog box.

Select whether to display arrows on the model that indicate whether the zone was interpolated from top down (), bottom up (), or by stretch squeeze ().

Select either Type 1 or Type 2 based on the following:
Type 1 (Recommended) Starting at either the top or bottom of the zone, depending on the Interpolate well option selected above, GeoSyn takes a data sample from each well and fills the distance between wells using interpolation based on distance and then moves to the next data point above or below the current position and repeats the above process. If a pinch-out occurs where one of the wells has no more data, GeoSyn switches from interpolation to extrapolation mode using the remaining data in the other well. This rapid switch from interpolation to extrapolation mode over only a single sample can generate a false reflection -especially in zones with strong horizontal velocity gradients.
Type 2 Data values are interpolated between two points on adjacent wells just as above, but when a pinch-out occurs instead of switching to extrapolated mode, GeoSyn continues to interpolate using the last value from the well that ran out of data. This may result in an interpolation that's heavily biased by the last data value in the pinched out wedge and if that value is radically different than other data in the well, it may generate an incorrect amplitude.