Updated GIS Quiz 3

Coordinate System

A framework used to define locations on a map.

Geographic Coordinate System (GCS)

A system that records locations using latitude and longitude (angular measurements).

Projected Coordinate System (PCS)

A coordinate system that overlays a grid onto a projection, allowing for distance and area measurements in linear units.

Reference Ellipsoid / Datum

A mathematical model approximating the Earth's shape, used as a base for projections.

Standard Parallel

A latitude line where a map projection touches the reference ellipsoid, minimizing distortion.

Central Meridian

The vertical centerline of a map, which serves as a reference for longitude values.

False Easting

A numerical adjustment added to east-west coordinates to avoid negative values.

False Northing

A numerical adjustment added to north-south coordinates to avoid negative values.

Cartesian Coordinate System

A grid system using X (east-west) and Y (north-south) values to define locations.

Eastings

The X-coordinates in a Cartesian system, measuring distance east or west.

Northings

The Y-coordinates in a Cartesian system, measuring distance north or south.

False Origin

A shifted starting point in a coordinate system to ensure all values are positive.

Universal Transverse Mercator (UTM)

A global coordinate system that divides the Earth into 60 zones, each using a Transverse Mercator Projection.

State Plane Coordinate System (SPCS)

A coordinate system used in the U.S. for land parcel mapping, using feet instead of meters.

Transverse Mercator Projection

A cylindrical projection with a north-south tangent line, commonly used in UTM and State Plane zones.

Lambert Conformal Conic Projection

A conic projection preserving shape and used for east-west-oriented State Plane zones.

Albers Equal-Area Conic Projection

A projection that preserves area, commonly used for mapping the United States.

Web Mercator Projection

A modified Mercator projection optimized for web maps, used by Google Maps and ArcGIS.

Equal-Area Projection

A projection that maintains correct land area proportions but may distort shapes (e.g., Albers Equal-Area Conic).

Conformal Projection

A projection that preserves angles and shapes but distorts area (e.g., Mercator Projection).

Loxodrome

A line crossing all meridians at a constant angle, used in navigation.

Graticule

A network of latitude and longitude lines on a map.

Tangent Projection

A projection where the developable surface touches the Earth at a single point or line.

Secant Projection

A projection where the developable surface cuts through the Earth, creating two standard parallels.