GIS Dictionary

NAD 1927

Acronym for North American Datum of 1927. The primary local horizontal geodetic datum and geographic coordinate system used to map ...

NAD 1983

Acronym for North American Datum of 1983. A geocentric datum and graphic coordinate system based on the Geodetic Reference System ...

nadir

1 In aerial photography, the point on the ground vertically beneath the perspective center of the camera lens. ...

NAICS

Acronym for North American Industry Classification System. A system for classifying individual business locations by their types of ...

natural neighbors

An interpolation method for multivariate data in a Delaunay triangulation. The value for an interpolation point is estimated using weighted ...

navigate

To interactively change the observer's or target's position using a tool designed for this purpose, such as the ...

navigation

1 The combined mental and physical activities involved in traveling to a destination, often a distant or unfamiliar one. ...

neatline

The border delineating and defining the extent of geographic data on a map. It demarcates map units so that, ...

network

1 An interconnected set of points and lines that represent possible routes from one location to another. For ...

network dataset

A collection of topologically connected network elements (edges, junctions, and turns) that are derived from network sources, typically ...

network trace

A function that performs network analysis on a geometric network. Specific kinds of network tracing include finding features ...

NMEA

Acronym for National Marine and Electronics Association. A nonprofit association composed of manufacturers, distributors, dealers, educational institutions, and others interested ...

NoData

In raster data, the absence of a recorded value. NoData does not equate to a zero value. While ...

node

1 In a geodatabase, the point representing the beginning or ending point of an edge, topologically linked to ...

noise

1 In remote sensing, any disturbance in a frequency band. 2 Any irregular, sporadic, or random ...

normal form

A set of guidelines for designing table and data structures in a relational database. When followed, normal form ...

normalization

The process of organizing, analyzing, and cleaning data to increase efficiency for data use and sharing. Normalization usually ...

NOTAM

Acronym for Notice to Airmen. An advisory bulletin containing information about the National Airspace System, typically time-sensitive information between ...

NSDI

Acronym for National Spatial Data Infrastructure. A federally mandated framework of spatial data that refers to U.S. locations, as well ...

NTM

Acronym for Notice to Mariners. A periodical update to existing nautical charts, issued by maritime authorities.

nugget

A parameter of a covariance or semivariogram model that represents independent error, measurement error, or ...

null hypothesis

A statement that essentially outlines an expected outcome when there is no pattern, no relationship, and/or no systematic cause ...