Pencils and pens are used for plotting data on maps or photographs, for
taking field notes, and for marking samples. The one used for plotting on a
base map must make fine lines that are easily visible, will not smudge, and
are erasable. The choice will vary with the climate and the operator but is
generally a well-sharpened pencil of about 2H hardness. Mapping on plastic.
base photographs such as those currently supplied by the U.S. Geological
Survey (Section 7-1) requires a sharply pointed ink.flow pen (as a Pilot ultra-
fine-point, Perntanent, SC- UF). Red or green pens mark black and white
photographs more legibly than black or blue pens. Pens should be tested on