GIS CHPT 2

One type of map projection that retains certain accurate directions. Azimuthal also refers to one type of map projection that uses a plane as the projection surface.

The central parallel and the central meridian. Together, they define the center of the origin of a map projection.

A ground-measured spheroid, which is the basis for the North American Datum of 1927(NAD27).

One type of map projection that preserves local shapes.

One type of map projection that uses a cone as the projection surface.

One type of map projection that uses a cylinder as the projection surface.

The basis for calculating the geographic coordinates of a location. A spheroid is a required input to the derivation of a datum.

A measurement system for longitude and latitude values such as 42.5^o.

A measuring system for longitude and latitude values such as 42^o30'00", in which 1 degree equals 60 minutes and 1 minute equals 60 seconds.

A model that approximates the Earth. Also called spheroid.

One type of map projection that maintains consistency of scale for certain distances.

One type of map projection that represents areas in correct relative size.

A value applied to the origin of a coordinate system to change the x-coordinate readings.

Avalue applied to the origin of a coordinate system to change the y-coordinate readings.

Geographic coordinates that are based on a spheroid.

A database developed by the U.S Bureau of Land Management (BLM) to include longitude and latitude values and other descriptive information for section corners and monuments recorded in the PLSS.

A location reference system for spatial features on the Earth's Surface.

A satellite-determined spheroid for the Geodetic Reference System 1980.

A common map projection, which is the basis for the SPC system for many states.

The angle north or south of the equatorial plane.

The angle east or west from the prime meridian.

A systematic arrangement of parallels and meridians on a plane surface.

Lines of longitude that measure locations in the E-W direction on the geographic coordinate system.

North American Datum of 1927, which is based on the GRS80 speroid and has its origin at the center of the spheroid.

Lines of latitude that measure locations in the N-S direction on the geographic coordinate system.

Same as the scale of the reference globe.

A plane coordinate system that is based on a map projection.

The process of transforming the spatial relationship of features on the Earth's surface to a flat map.

A land partitioning system used in the United States.

A reduced model of the Earth, from which map projections are made. Also called a nominal or generating globe.

Projection of spatial data from one projected coordinate system to another.

Ratio of the local scale to the scale of the reference globe. The scale factor is 1.0 along a standard line.

A model that approximates the Earth. Also called ellipsoid.

Line of tangency between the projection surface and the reference globe. A standard line has no projection distortion and has the same scale as that of the reference globe.

A standard line that follows a meridian.

A standard line that follows a parallel.

A coordinate system developed inthe 1930s to permanently record original land survey monument locations in the United States. Most states have more than one zone based on the SPC27 or SPC83 system.

A common map projection, which is the basis for the UTM grid system and the SPC system.

A grid system that divides the polar area into a series of 100,000-meter squares, similar to the UTM grid system.

A coordinate system that divides the Earth's surface between 84^o N and 80^o S into 60 zones, with each zone further divided into the northern hemisphere and the southern hemisphere.

A satellite-determined speroid for the World Geodetic System 1984.

A value applied to x-coordinate readings to reduce the number of digits.

A value applied to y-coordinate readings to reduce the number of digits.