midterm review- georeferencing Flashcards
list the 5 steps of map making
Selection Simplification exaggeration and displacement classification symbolization
What is a topographic map and what is a thematic map?
Topographic map shows many natural and cultural geographic features
Thematic map has one interest
List and the three types of thematic maps
Choropleth map Area class map Isoline map
What are the 3 types of map scales?
Verbal statement
representative fraction
graphic scale
Which scale shows area in greater detail? small or large?
large
How many ft is in 1 second?
100
How to convert minutes and seconds into decimal degrees and how many decimal digits of DD should we keep?
dd=Degree+ m’/60+s”/3600
keep 6 decimals.
What is a geoid?
A mathematical figure of the earth’s surface.
What is an ellipsoid?
3D model used to approximate the geoid.
What is the latest global datum?
World Geodetic System 1984
Name for deviation between geoid and reference ellipsoid.
geoid undulation
Map projections are a system in which _on the _ _ of the Earth are displayed on a _ _ or surface according to some sets of rules
locations
curved surface
flat sheet
Who created the Tissot’s Indicatrix
Nicolas Tissot
What are the 3 map projection properties?
Equivalence
equidistance
conformality
what are the 3 physical classes of map projection?
Cylindrical
Conic
Azimuthal/planar
What are the 3 aspects of map projections?
Normal (parallel)
Transverse (perpendicular)
Oblique (other)
Is it possible for equidistant maps to have the correct distance both along the meridians and the parallels?
No
What does an equivalent map represent correctly?
area sizes
Which map projection is good for navigation?
Conformal
Which projection have right angel intersections for meridians and parallels?
Conformal.
What are great circle paths? and on what projection are they shown are straight lines?
Shortest routes between points on a sphere. Gnomonic.
What are rhumb lines? and what projection has them?
Lines of constant direction. Mercator.
What’s the term for when a projection surface is tangent or secant at the equator? what about at the pole?
Equatorial. Polar.
what are the 3 criteria for choosing a map projection?
shape and size of area
position of the area
purpose of the map
Physical class should be based on what? To minimise distortion, what physical class would you choose for a small circular area? what about a large rectangular area? and a triangular area?
based on shape and size of geographical area mapped.
azimuthal. cylindrical. conic.
When selecting aspect, it is optimal for the projection centre to coincide with the _ of the area, or when the _ _ is located along the _ _ of the area to be mapped.
centre
projection plane
main axis
The property of the projection is selected based on the _ of the map
purpose
The cylindrical projections can either be _ to the globe along a _ circle, or _ to the globe along 2 _ circles.
tangent, great.
secant, small
for cylindrical projections, distortion _ with distance from _ _
increases
standard lines
_ _ is useful for projections of mid-latitude regions.
Conic projection
Cone _ to globe along 1 small circle or _ along 2.
tangent
secant
_ _ is useful for polar regions or small areas with equal N-S and E-W extent
azimuthal projections
Give an example of a conic conformal projection, a cylinder conformal projection, a conic equivalent projection, and an azimuthal equivalent projection
Lambert conformal- used in north america because of distortion below the equator
Mercator- distortion in north and south poles.
Albers equal area- scale true along standard parallels.
Lambert equivalent
_ _ _ projection is widely accepted for topographic mapping purposes
Universal Transverse Mercator
