how to make a markable diagram in a fillable pdf form

[kwm13]

i'm creating a fillable form, and the question I have is not about the fields.  there is a section with a diagram, which the person filling out the form needs to be able to mark arbitrary point on.  Any suggestions about how to handle this?

[Nancy OShea]

[Moderator moved from Using the Community (forums) to Acrobat.]

[try67]

They can use one of the commenting tools for that, such as a Stamp.

Another option is to create a (transparent) field over this area and then use a script to add the comment at the spot where they click on that field, but that's a bit more complicated, of course.