Necessary details are emphasized and others are subordinated. These are designed and constructed specifically for air navigation. The scale is small so that large areas can be shown on a single sheet. Ground features that are prominent from the air are emphasized in bold and simple symbols. Other features of equal importance on the ground but less noticeable from the air are subdued or omitted entirely.
Elevation is shown by gradient tints.
Navigational data are shown by bright overprinting. These are prepared from public land surveys and are designed to present land survey data. They usually cover a survey unit, such as a township. The scale is large. Courses and distances, subdivisions of sections, acreage figures, and other data from the survey are shown.