Module 2 Flashcards
What is the geographic grid?
and define the terms latitude and longitude
Geographic grid consists of a set of intersecting circles; once it extends north and south and the ones that extends east and west.
The prime meridian and equator are both great circles that bisect earth into two equal halves. These represent the shortest distance between any two points on earth
Latitude is an angular distance north or south of the equator measured from the centre of earth.
Longitude is an angular distance east or west of a point on earth’s surface measured from the centre of the earth
What are the three common types of thematic maps?
Dot maps:Suitable for displaying non-continuous or discrete data that vary from one place to another
choropeth maps: Represent data by using different colours or intensity of shading. Used for data that are sorted into classes.
Isoline maps: isolines are lines connecting points of equal value on a map. Example a topographic map
Map projections: transfer of spatial data from 3 to 2 dimensions result in the distortion of the shape or area of objects, or distances between objects displayed on a map.
What are the five classes of map projections?
Conformal: maintains the true shape of objects but area of objects is distorted
Equivalent: maintains true area or size of objects but shape of objects is distorted
Conic : best suited for landmasses with East West orientations or small countries
Planer: gnomonic; meridians are straight lines radiating from a central point. Parallels are complete circles. Useful for focussing on single regions and often used for accurate views of the poles
Goodes interrupted equal area projection:
Mathematically created map that is interrupted over ocean basins to minimize distortion of landmasses and create an equivalent projection
How is map scale portrayed on Maps?
Map scale relates to the size of features on a map to the actual size in the real world and relate distance between the features on a map to the actual distance on earth.
In regards to Isolene maps: define the terms contour lines, isotherms, isobars, and isohyets
Contour lines: elevation
Isotherms: temperature
Isobars: atmospheric pressure
Isohyets:Precipitation
Distinguish between passive and active remote sensing.
Note: remote sensing is a new approach to spatial Analysis that involves measuring properties of the environment without direct contact
Passive remote sensing uses instruments to detect energy emitted from the surface of earth. Ex) Camera and aerial photographs
Active remote sensing uses instruments that admit their own radiation and then detect and analyze what is reflected back
Ex)Radar- radio detection and ranging
What are geographic information systems?
GIS is a system for storing, analyzing, and manipulating specially reference data. GIS databases consist of several of individual data layers. A data layer contains measurements for specific geographic variable, such as vegetation, soil, hydrology, road networks, municipal infrastructure etc.
What are five elements of GIS?
Data acquisition, data processing, data management, data manipulation, and generating maps
