Lecture 7: Map Projections

These flashcards cover key concepts from the lecture on coordinate systems, datums, and map projections in Geographic Information Systems.

Geographic information systems are different from other information systems because they contain __.

spatial data

One of the primary challenges in defining a coordinate for Earth’s surface is the __ of the Earth.

shape

The study of the shape and size of the Earth and its gravity field is known as __.

Geodesy

The actual surface of the Earth is more like the surface of a __ than a perfect sphere.

potato

The Earth is actually a __, slightly larger in radius at the equator than at the poles.

spheroid

Geodesy involves studying the Earth's gravity fields which are affected by different __ materials.

density

The method of 'unique addressing' for places on the Earth's surface requires __ to assist in locating them.

coordinates

A Geodetic Coordinate System identifies positions in terms of latitude, longitude, and __.

height

Latitude measures the position to from the equator.

east; west

Longitude measures the position to from the Prime Meridian.

north; south

Height in geodesy refers to how high we are above or below __.

something

The mathematical model used to describe the Earth's shape is called an __.

ellipsoid

Mean sea level and our mathematical model are considered to be __ surfaces.

reference

Regions on Earth can dip or bulge due to differences in density, resulting in an undulating shape known as __.

geoid

The geoid is complex and cannot be directly __.

modeled

Ellipsoids are best fit mathematical shapes used to average out the Earth's __.

shape

Elevation is defined as the vertical distance above the __.

geoid

Orthometric height is the height above the geoid, while __ height is the height above the ellipsoid.

ellipsoidal

The difference between ellipsoidal height and geoidal height is called __ height.

orthometric

Geoidal variation in the Earth’s shape is the main cause for different __ being employed in different parts of the world.

ellipsoids