Chapter 2: Portraying Earth Flashcards
What is the difference between a globe and map?
A glove is a true representation of the Earth while a map is a flat representation, reduced in size, that highlights specific information.
The degree of distortion on a map is related to what two factors?
- The size of area shown on the map
2. The scale of the map
What is a map scale?
The relationship between the distance measured on a map and the actual distance it represents on Earth’s surface.
Describe the three most popular map scales.
- Graphic- uses a line marked off in distance to represent actual distance on Earth’s surface
- Fractional- uses a fraction or ratio to represent distance
- Verbal- expresses distance using words
What is a map projection?
A system for transferring the Earth’s spherical surface onto a flat surface
What is map equivalence and conformality and the relationship between them?
Equivalence is the degree of correct ratio maintained over an entire map between the map and its corresponding Earth surface. Accurate regarding size.
Conformality is the degree to which proper angular relationships are maintained across the entire map. Accurate regarding shape
Equivalence and conformality share an inverse relationship; as one increases the other decreases.
How does one create a cylindrical projection?
By wrapping a piece of paper around a globe such that only the equator touches.
What are loxodromes?
A line on the surface of a sphere that crosses all meridians at the same angle and represents a line of constant compass direction
How does one get a planar projection?
Projecting the markings of a center lit globe tangent to one point, usually the N/S Poles. Typically only show one hemisphere
How does one make a conic projection?
Wrapping a cone around the Earth tangent to, or intersecting, a portion of the pole. Best for regions of E/W orientation in mid latitudes
What is a pseudocylindrical projection?
A projection that wraps around the equator like a cylindrical projection but curves in toward the poles to convey the curvature of the Earth
Describe the basic components of a map
- Title: conveys area covered and indicates content of map
- Date: the time span over which the map data was collected and/or published
- Legend: explanation of symbols and other markings on map
- Scale
- Direction
- Location
- Data source
- Projection type
What is an isoline and what are some common types?
Isolines are limes that join points of equal value. Common isolines include:
- Elevation contour lines- displays elevation
- Isotherms- displays temperature
- Isobar- displays pressure
- Isohyet- displays precipitation
- Isogonic- displays magnetic declination
What is remote sensing?
Data collection by a device not in physical contact with the object under study.
What are the orbits satellites occupy
Low (altitude <20,000) and geosynchronous (36,000 km or 22,400 miles)
