If possible, locations are checked while mapping is in progress. Place names are verified with an authoritative source. Keeping records of field sheets. The index map outlines and identifies all of the field sheets of the survey. Where single-lens aerial photographs are used, several hundred individual sheets are required and a systematic means of identifying their locations in the survey area is needed.
Photographic indices are available for most areas where photographs are used.
Each field sheet should contain the name of the survey area, the State, the date of the survey, and the names of the soil scientists who mapped that sheet. Names of others who inked or checked the sheet and its scale may be given also. Commonly, all this information can be put only on the back of the sheet. If it can be put on the front, it may be placed so that it will appear on photographic copies. A stamp can be used to provide spaces for the information.