e. Airfield-engineering and NAVAID surveys are used to determine any combination of the
following:
The location of obstacles within 10 nautical miles of an airfield center.
The dimensions of runways and taxiways, the height of flight towers, and the availability of
NAVAIDs.
The safe approach angles to runways and the minimum safe glide angle.
The elevation of the barometer on an airfield.
The positions and azimuths of points designated for INS checkpoints.
The requirements of the Federal Aviation Administration (FAA), the USAASA, or an
equivalent military activity.
The information used to assist a military-aircraft crash or disaster incident investigation.
f. Hydrographic surveys are performed on large bodies of water to determine the channel depths
for navigation and the location of rocks, sandbars, lights, and buoys. In rivers, these surveys are
performed to support flood-control projects, power development, navigation, water supplies, and water
storage.
g. Field classification and inspection surveys can help to identify features not normally revealed
using a compiler, such as political-boundary lines, names of places, road classifications, and buildings
obscured by trees. These surveys can also clarify aerial photographs by using comparisons with actual
ground conditions.
h. Land surveys are used to locate boundaries and tracts of land on a city, county, state, national, or
international level.
i. Inertial surveys are used to determine relative positions and azimuths. The Position and Azimuth
Determination System (PADS) is now being used extensively to support artillery surveys.
PART F - SURVEY NETWORKS
2-9. General. Each survey has a fundamental classification of control points called a network. There
are several different types of networks. A network of control areas usually establishes horizontal and
vertical SCPs within a country. These areas are all referenced to a single datum and are related in
position or elevation to each other. Networks are called basic, supplementary, and auxiliary. All
horizontal networks in the US are referenced to the North American Datum of 1927 (NAD 27) and
North American Datum of 1984 (NAD 84) with coordinates currently published
2-7
EN0593
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