Topic 02 pt 1

Question 1

consequences of distortions for average viewer

Answer 1

they create misconceptions

Question 2

projection process

Answer 2

locating things on earth
ellipsoid vs sphere

Question 3

scale reduction

Answer 3

amount is the principiple cartographic scale
all of these items are apart of the datums GCS sequence

Question 4

projection sequence

Answer 4

projection of 3d surface onto a flat 2d plane

Question 5

what does PCS do

Answer 5

tell me how to draw earth on a flat 2d surface

Question 6

what does GCS do

Answer 6

tell me where on earth the data should draw

Question 7

WKID

Answer 7

well known ID

Question 8

Latitude

Answer 8

up, down, N, S
lines are horizontal
how far above or below equator

Question 9

longitude

Answer 9

Left, right, E, W

lines run up-down
measurements of east/west of greenich

Question 10

geocentric

Answer 10

angular measurement

Question 11

geodetic

Answer 11

extension to top of plane

curved (non planar)

Question 12

N,E,S,W (+-_

Answer 12

NE +
SW -

Question 13

how many seconds in a minute, how many minutes in a degree

Answer 13

60s in a minute, 60 minutes in a degree

Question 14

what is a map projection

Answer 14

orderlly system of parallels and meridians drawn on a flat surface
3d model onto a 2d surface
choice of projection depends on what the purpose o the map is

Question 15

global scale projection =

Answer 15

projection matters more, model of earth does not

Question 16

small area projection =

Answer 16

projection matters less, model of earth matters more

Question 17

plate carree

Answer 17

most simple mathematical projection

Question 18

projection families based on developeable surfaces

Answer 18

plane, cone, cycinder,

UTM complimentary to UPS

Question 19

azimuthal orthographic

Answer 19

more common for global things
designed to mimic how earth looks from space

light coming from a long distance away

Question 20

azimuthal stereographic

Answer 20

lightbulbs inside the globe near the middle

lat and long lines appear curved

Question 21

azimuthal gnomonic

Answer 21

source at centre of earth
used for navigation charts

Question 22

common cylindrical projections

Answer 22

mercator - wrapped around the equator

transverse mercator - wrapped around poles

Question 23

common conic projections

Answer 23

albers equal areas conic

lambert conformal conic
Canadian go to

Question 24

map projections based on distortions

Answer 24

shape, area, distance, direction

each projection is designed to achieve at least one or two of these to conserve

Question 25

tissot;s indicatrix

Answer 25

angle yes, area no = conformal angle no, area no = compromise angle no, area yes = equal area

Question 26

conformal

Answer 26

isotropic scale is same in every direction shapes for small areas are portrayed accurately ex. lambert conformal conic

Question 27

equal area

Answer 27

anisotropic scale is not the same in every direction shapes are distorted ex. albers equal area

Question 28

equidistant

Answer 28

preserves distance usually between 2 directions mercator most notable

Question 29

tangent CASE

Answer 29

developable surface touches the globae at ONE point stretching where paper is above the globe scale at tangent line = 1:1 (principle scale) scale factor how the scale changes towards the edges

Question 30

secant CASE

Answer 30

paper inside the globe end scale factor stretched (gets bigger) middle scale factor shrinks (gets smaller) make more of the mpped area to have better distortion because of the scale factor being spread out distributed scale factor error more evenly

Question 31

concept of PCS

Answer 31

want to get away from spherical coordinates concept of overlapping cartesian coordinate over the earth model you can located (0.0) anywhere you want

Question 32

standard line

Answer 32

points or lines where the tangency touches the globe projection plane in contact with the projection globe, where the SF is 1 or 1:1 trangency = line = equator secant = two lines = one above one below

Question 33

UTM

Answer 33

one type of projection applied many times around the world strips around the globe 60 strips x 6 degrees wide = 360 degrees goes to 84 degrees north and 80 degrees south each strip is a numbered zone (alberta 11 and 12)

Question 34

how many locations can be described by one eating and northing

Answer 34

120

Question 35

UTM grid

Answer 35

horizontal lines (northings) vertical lines (eastings) grid is only ever aligned north/south at the central meridian 500,000m Canada only northings always 7 digits eastings usually 6 never 7

Question 36

PCS 3 components

Answer 36

2d surface to define locations 3 components a GCS to locate on earth set of rules on how to flatten spatial data rules how to set up the cartesian system NAD 83 = GCS UTM 11N is the projection

Question 37

central meridian

Answer 37

where the projection is centered

Question 38

latitude of origin

Answer 38

bottom of the projection or projected cartesian system

Question 39

scale factor formula

Answer 39

scale factor = actual scale/principle scale

Question 40

1 mile =

Answer 40

1760 yards 5280 feet 63,360 inches 1609.34 meters 160934 cm