Chapter 3 Datums 97 When the area is too small to accurately or clearly display on a drawing, then a datum target point is used at the center location. The top half of the datum target symbol identifies the diameter of the target area, as shown in Example 3-22. Fixture base The Drawing The Fixture Setup (Enlarged View) 3X ∅6 locating pins X3,∅6 X2,∅6 X1,∅6 Datum feature Part Datum plane X Example 3-22. When the datum target area is too small to show, the datum target point is used and the target area size is given in the top half of the datum target symbol.