GIS-Quiz 2

Projection

A mathematical transformation converting 3D geographic coordinates into 2D Cartesian coordinates.

Cartesian Coordinates

A coordinate system that represents locations with X (horizontal) and Y (vertical) values.

Reference Ellipsoid / Datum

A model of Earth's shape that accounts for variations in sea level and gravitational pull.

Geoid

A model representing Earth's sea level variations without topography.

Developable Surface

A geometric shape (plane, cylinder, or cone) onto which the Earth's surface is projected.

Standard Parallel

A line on a map where distortion is minimized, usually where the projection touches the reference ellipsoid.

Planar (Azimuthal) Projection

A projection using a flat surface, often used for polar regions.

Cylindrical Projection

A projection where the Earth is wrapped in a cylinder, commonly used for world maps.

Conic Projection

A projection that uses a cone, ideal for mid-latitude regions.

Equal-Area (Equivalent) Projection

A map that preserves area but distorts shape (e.g., Gall-Peters Projection).

Conformal Projection

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

Equidistant Projection

A map that preserves distance along specific lines but distorts shapes and areas (e.g., Azimuthal Equidistant Projection).

Compromise Projection

A projection that balances distortions to make the map more visually appealing (e.g., Winkel Tripel Projection).

Loxodrome

A line that crosses meridians at a constant angle, useful for navigation.

Tissot’s Indicatrix

A visual tool using circles to show distortion on a map.

Secant Projection

A projection with two standard parallels where distortion is minimized.

Tangent Projection

A projection with a single standard parallel.

Gall-Peters Projection

An equal-area map that accurately represents landmass sizes but distorts shape.

Mercator Projection

A conformal map that preserves shape but distorts area, especially near the poles.

Azimuthal Equidistant Projection

A map that preserves distance from a central point but distorts other areas.

Equirectangular Projection

A simple projection that divides the Earth into a rectangular grid but causes severe distortion at the poles.

Winkel Tripel Projection

A compromise projection used by National Geographic that balances distortions of area, shape, and distance.