GIS Dictionary

Acronym for North American Datum of 1927. The primary local horizontal geodetic datum and geographic coordinate system used to map the United States during the middle part of the twentieth … Read more

Acronym for North American Datum of 1983. A geocentric datum and graphic coordinate system based on the Geodetic Reference System 1980 ellipsoid (GRS80). Mainly used in North America, its measurements … Read more

1 [aerial photography] In aerial photography, the point on the ground vertically beneath the perspective center of the camera lens. 2 [astronomy] In astronomy, the point on the celestial sphere … Read more

[data structures] Acronym for North American Industry Classification System. A system for classifying individual business locations by their types of economic activity. The statistics agencies of Canada, Mexico, and the … Read more

[mathematics] Acronym for not a number.

[coordinate systems] The datum established in 1929 by the U.S. Coast and Geodetic Survey as the surface against which elevation data in the United States is referenced.

[cartography] A method of manual data classification that seeks to partition data into classes based on natural groups in the data distribution. Natural breaks occur in the histogram at the … Read more

An interpolation method for multivariate data in a Delaunay triangulation. The value for an interpolation point is estimated using weighted values of the closest surrounding points in the triangulation. These … Read more

[ESRI software] To interactively change the observer’s or target’s position using a tool designed for this purpose, such as the navigate or fly tool. There are three contexts in which … Read more

1 [wayfinding] The combined mental and physical activities involved in traveling to a destination, often a distant or unfamiliar one. Navigation comprises wayfinding and locomotion. 2 [geography] The activity of … Read more

[GPS] The name of the U.S. Department of Defense’s Global Positioning System (GPS).