Map instructions are placed around the outer edge of the map and are called marginal information.

The index to boundaries diagram shows the boundaries that occur within the map area, such as county lines and state boundaries. The index of boundaries diagram appears in the lower right margin of all map sheets.

Maps contain a diagram that illustrates the adjoining map sheets. The adjoining sheets diagram usually contains nine rectangles, but the number may vary depending on the locations of the adjoining sheets.

The elevation guide is a miniature characterization of the terrain shown. The terrain is shown by bands of elevation, spot elevations, and major drainage features. The elevation guide helps you to rapidly identify major landforms. It is normally found in the lower right margin.

The declination diagram indicates the angular relationships of true north, grid north, and magnetic north. Recent edition maps have a note indicating how to convert azimuths from grid to magnetic and from magnetic to grid, next to the declination diagram. The declination diagram is located in the lower margin.

The contour interval note states the vertical distance between adjacent contour lines on the map (i.e., Contour Interval = 20-meters; Supplementary Contours = 10 meters). The contour interval note is found in the center of the lower margin normally below the bar scales.

Bar scales are used to convert map distance to ground distance. Maps may have three or more bar scales, each in a different unit of measure. The bar scales are located in the center of the lower margin.

The legend illustrates and identifies the topographic symbols used to depict some of the more prominent features on the map (i.e., railroad tracks, buildings, swamps, etc.). The symbols are not the same on every map. Always refer to the legend to avoid error when reading a map. The legend is located in the lower left margin.

The sheet number is used as a reference number for that map sheet. It is found in two places: the upper right margin and the lower left margin.

The series number is a sequence reference expressed either as a four-digit number (i.e., 1125) or as a letter, followed by a three or four-digit number (i.e., M556; N3341). It is found in both the upper right margin and the lower left margin.

The edition number represents the age of the map in relation to other editions of the same map and the agency responsible for its production. A map bearing a higher edition number is assumed to contain more recent information than the same map bearing a lower edition number. The edition number is found in the upper right margin and in the lower left margin.

A map is named after the most prominent cultural or geographic feature. The sheet name is found in two places: the center of the upper margin and either the right or left side of the lower margin.

The scale note is a representative fraction that gives you the ratio of a distance on the map to the corresponding distance on the earths surface (i.e., 1:50,000 indicates that one inch on the map equals 50,000 inches on the ground). The scale is found both in the upper left margin after the series name and in the center of the lower margin.

The map series name is found in the upper left margin. It usually includes a group of similar maps at the same scale and/or the same sheet lines designed to cover a particular geographic area. The name given a series is that of the most prominent areas.

Series Name: CALIFORNIA.

Scale: 1:50,000.

Sheet Name: MARGARITA PEAK.

Edition Number: 7-DMATC.

Series Number: Series V795.

Sheet Number: Sheet 2550 IV.

Legend.

Bar Scales.

Contour Interval Note: ELEVATION IN METERS.

Declination Diagram.

Elevation Guide.

Adjoining Sheet Diagram.

Index to Boundaries.