Target height

The value you enter in the Target height field depends on the prism you are using and whether you are measuring the true height of the prism or to the bottom notch on a Trimble prism base. The default method is to measure the true height of the prism.

When measuring to the bottom notch on a Trimble prism base, tap and then select Bottom notch. Trimble Access corrects this measured slope value to true vertical and adds the offset 0.158 m (0.518 sft) to calculate the true vertical height to the center of the prism.

If you select Bottom notch, the minimum slope distance (Hm) that you can enter is 0.300 meters. This is approximately the minimum slope distance that can be physically measured. If the minimum is not low enough, you must measure to the top mark.

Refer to the following figure and table.