Vertical datum The reference or basis for elevations (usually mean sea level).
Find out more about the National Topographic System, UTM Projection, and Symbols used on NTS maps.
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[edit] Vertical datums
A vertical datum is used for measuring the elevations of points on the earth's surface.
Vertical datums are used to measure heights given on maps. The starting point for measuring these heights are Mean Sea Level points established at coastal places.
A vertical datum in which zero height is defined by a particular tidal surface, often mean sea level. Examples of tidal surfaces include mean sea level, mean low water springs, and mean lower low water.
North American Vertical Datum of 1988
navigable airspace
airspace at and above the minimum flight altitude that is prescribed in FARs, including airspace needed for safe takeoff and landing ...
§ Earth's Shape and Vertical Datums
§ Geographic Coordinate System (latitude and longitude)
§ Map Projections Defined ...
national geodetic vertical datum of 1929 Reference surface established by the U.S.
the horizontal and vertical datum flags set for NGVD29 and NAD27,
respectively when I wrote the program. The horizontal datum flag should definitely be set to 3, (not 1like I had it in the program.) I am not sure what ...
Vertical datums deal primarily with elevation and are usually developed to supplement existing datums. Horizontal datums deal with assigning coordinates to positions on the surface of the earth based on a two-dimensional plane.
The solution provides an interface to manage horizontal and vertical datum dataset parameters.
Spatial data are referenced to a horizontal datum and a vertical datum, both of which are based on a mathematically calculated shape of the earth.
ground control - Physical points on the ground whose positions are known with respect to some horizontal coordinate system and/or vertical datum.
The World Geodetic System 1984 (WGS 84) horizontal datum and the National Geodetic Vertical Datum of 1929 (NGVD 29) were selected for OPPS on the basis of the availability of digital elevation model (DEM) data.
NAVD: North American Vertical Datum
NDIS: Network Driver Interface Specification
NFS: Network File System ...
[geodesy] The reference specifications of a measurement system, usually a system of coordinate positions on a surface (a horizontal datum) or heights above or below a surface (a vertical datum).
It most often refers to either a horizontal standard, such as a particular spheroid for referencing coordinate positions, or it refers to a vertical datum, such as mean sea level, from which elevations are referenced.
The corresponding datum is the basis for a planar coordinate system. For example the North American Datum, NAD83 is the horizontal datum and North American Datum NAVD88 is the vertical datum for coordinates used in Delaware County's GIS.
 See also: Datum, Mapping, Elevation, Geographic, Map
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