a. Abbreviations on the face of the map are held to an absolute minimum. They are employed only where space prohibits the use of a full term or where use of the full term would require unreasonable repetition.
b. Periods are omitted from abbreviations on the face of the map. In the margin, periods normally are retained. They are, however, omitted from coded abbreviations of governmental agency names. In such cases, no spacing is shown between the coded letters.
c. In addition to the abbreviations listed herein, commonly accepted abbreviations of time, measures, and countries are authorized.
