Profile surface point indicators

[obie18]

Hello,

I am wondering if anyone can help with a question I have regarding profile of a surface. Is there a rule of thumb as to when point indicators should or should not be used. I can not find a definitive answer in the standard (Y14.5M-1994).

 

[weavedreamer]

When you have a specifc zone you wish to control, or when the desired is not self-evidently clear.