Maps and geomatics Flashcards
what unites all geography
maps
what is a powerful tool for spatial analysis
map
what is a map
generalized view of an area (model) a seen from above and reduced in size
what are 4 things to consider in a map
- types
- map elements
- coordinate system
- projections
reduce
a down-scale of something
spatial analysis
ability to answer spatial questios
map elements refers to the
different symbol used
what is geomatics
the digital mapping of earth
true or false
geomatics is a geographical tool
TRUE
what allows the answer for spatial questions in geography
geomatics
what is the benefit of using an overlay of layers
allows us to see commonalities
what is the unifying stream for all of geography
geomatics
what 3 characteristics are maps classed by
- scale
- function
- subject matter
scale in a map refers to
degree of reduction
what are three examples of map function
- charts
- general reference maps
- thematic/special purpose maps
what are 4 characteristics of maps?
- reductions
- transformations
- specific simplification/generalization
- signs and marks
why are reductions critical to maps
we don’t make exact duplicates of the real world because it’s not practicable
reductions are based on
map scale
map scale
defined dimensional relation between reality and the map
true or false
map scales are seemingly unitless
TRUE
transformations
transfer of one form to another
transformations are done in the form of
projection
projection
have to transform a spherical earth to a flat map
what is the result of projection
the map stretches
what is affected by projection (example)
calculations of distances
where are distortions caused by projection the most AFFECTED
the poles - they stretch the most
a specific simplification refers to
only the information that NEEDS to be on the map is what fits the purpose
specific simplification requires
- classification
- simplification
- generlization
accurate generalization falls under what character of a map
specific simplification
true or false
the world in infinitely complex
true
maps are not ______________-
100% representations of real world
accurate generalization
the decision on how to generalize/choose what is on the map to fit our purpose
is a generalization infinitely complex
NO
what are signs and marks used for on a map
to represent real features
what are the two categories of map scale
small scale and large scale
what is small scale
a “birds-eye view”/zoom out of a LARGE area
what is the scale for a small scale map
one unit of distance in reality is represented by a SMALL distance on the map
example of small scale
1:20 000 000
large scale maps offer
close up view of a SMALL area
large scale map scale
one unit of distance in reality is represented by LARGE distance on map
example large scale map scale
1:1000
what is the cutoff between small and large scale
1:50 000
is this a large or small scale map
large scale
is this a large or small scale map
small
general reference maps are a
large-scale topographic map
what map function does this show
general reference maps
thematic/special purpose maps
distribution of an attribute or relation among attributes
examples of thematic/special purpose maps
- political map
- population distribution
- number of births
what map function is this
thematic/special purpose map
what is a chart
a map meant to be worked on and added to
examples of charts
- nautical
- aeonautical
what are charts most often used for
navigation
what map function is this
chart
subject matter for maps can be either
cadastral or plans
cadastral means
a large scale subject matter
examples of cadastral subject matter
- property boundaries
what is cadastral often assess
taxataion
a subject matter focused on plans examples
- buildings and railways
plans are typically
large scale maps or diagrams
what type of subject matter is this
plan
what type of subject matter is this
cadastral
3 types of maps
- thematic
- planimetric
- topographic
thematic maps show
the spatial distribution of some type of data over a geographical area
planimetric maps show
the horizontal position of boundaries, bodies of water, economic and cultural features
topographic maps portray
physical relief through the use of contour lines that connect all points at the same elevation
what does relief refer to
what the shape of the earth looks like
true or false
thematic maps are both quantitative and qualitative
true
what type of map is this
topographic map
what type of map is this
planimetric map
what type of map is this
thematic map
what can be illustrated on a topographic map
- natural physical features
- infrastructure + human-made features
true or false
NTS maps have been made for ALL of Canada
true
what are 3 key elements of a topographic map
- contour lines
- reference grid
- scale
contour lines
connect areas of equal elevation
reference grid
explains where we are and specific locations
where is north oriented on a map?
top of the page
a contour is an
imaginary line that joins points of equal elevation above sea level
altitude vs elevation
altitude = above earth’s surface (on the ground)
elevation = height above sea level
what is your elevation on mount Everest
0 because still connected to the ground
contour lines are drawn at ______ elevation intervals
constant
how is the contour line slope calculated
elevation over the map distance
contour line slope
change in elevation per unit of horizontal distance
what is the rise for calculating contour slope
difference between the elevation of the top and bottom of the slope
what is the run for calculating the contour slope
distance measured on the map and converted to distance on the ground using the map scale
how do calculate the slope of contour lines in degrees
acrtangent (inv tan or tan-1) times (rise over run)
what are three different spacings for contour lines
- widely spaced
- narrowly spaced
- uniformly spaced
a widely spaced contour reflects
gentle slopes
a narrowly spaced contour reflects
steep slopes
uniformly spaced contours reflect
uniform slopes
consistent spacing of contour lines will create a
linear slope/straight line
contour lines that start tight at the top of a mountain and then become more spaced out will reflect
concave profile
contour lines that start spaced out and become tighter down the slop reflects
convex profile
what are 3 rules for contour lines
- never intersect
- never split or divide
- always closed (though it may run outside the map)
how is a hill represented in contour lines
concentric contours
how is a depression represented in contour lines
concentric hachured contour
how is a river valley represented in contour lines
in a V with the base pointing upstream
how is a ridge represented in contour lines
v or u shape with base pointing downwards
what landform is an obvious violation of topographic maps
overhangs
what does a 1:1 scale mean
its an exact replica (like 1 cm to 1 cm)
what are common scales for NTS maps in Canada
- 1 50 000
- 1: 250 000
a map scale is a representative
fraction or ratio
what are examples of written/verbal map scales
- 1cm = 1 km
- graphical
what is a reference grid used to define
absolute positioning (locations) on a map
what are two examples of coordinate systems
- longitude/latitude
- rectanagular grid systems (UTM)
what is a coordinate system used for
to locate points on a sphere
true or false
the coordinate systems can cover the whole Earth
true
what is a requirement for coordinate systems to work
if you know what the shape of the earth is
is the earth a perfect sphere
NO
what is the shape of the Earth
it’s not a perfect sphere but squished and not smooth and have bulges and depressions
what is a term used to describe how earth is squished
ellipsoid
what is the latitude/longitude grid based on
60/sexagesimal scale
where is the origin for the latitude/longitude grid
at the center of the earth
latitude measures
angular distance measured north and south of the equator
parallel refers to _____ in latitude
lines connecting the same latitude
do parallel lines intersect
NO
what is true north
geographic north pole
what is the latitude degree for true north
0 degrees latitude
what is magnetic north
point where magnetic field points vertically downwards
what north does our compass point to
magnetic north
true or false
earth is one big magnet
TRUE
what is magnetic declination
the angle between true north and magnetic north
why is magnetic declination important
its the way a compass is configured to point to true north instead of magnetic north
what is the magnetic declination correction for Lethbridge
13 degrees 29 minuets East
true or false
the north magnetic pole is headed for Siberia
TRUE
longitude is the
angular distance measured east to west on the earth’s surface
where is longitude relative to/the origin
prime Meridian at Greenwich England
Meridians
line connecting the same longitude
what is the term for the line connecting the same latitude
parallel
what is the term for the line connecting the same longitude
meridians
where do meridians converge
at the poles
why is there a discrepancy at the equator in the North Pole
because of the bulge found at the equator
what is bigger at the equator in the North Pole
longitude
true or false
longitude and latitude can abe used to find the position of any place on earth
true
how are latitude and longitude organized in coordinates
latitude first and then longitude
the rectangular grid systems are used for
smaller areas
what is the format for the rectangular grid system
(x,y) coordinates
what does UTM stand for
universal transverse Mercator
true or false
relatively small areas have minimal distortion and rectangular grid system can be used
TRUE
latitude and longitude systems are used for
large areas
UTM is used for
small areas
what is easting
distance from a meridian
what is northing
the distance from the equator
what are the 3 elements of UTM coordinates
- zone
- easting
- northing
what coordinate system are easting and northing used
UTM system
how are geographical and UTM coordinate systems positioned on the shape of the world
by a datum
datum is
how a coordinate system is seated over the ellipsoid
how to make a datum
covering a globe with a piece of paper
origin will be more accurate but the farther way will become less accurate
what are two datums used
- NAD 26
- NAD83
what ellipsoid did the NAD27 use
ellipsoid 1886
what ellipsoid did the NAD83 use
ellipsoid 1983
what is a datum
a coordinate system with a reference surface that serves to provide known locations to begin surveys and create maps
GPS is a
navigational tool developed for military purposes
what does a GPS system consist of
satellites and a receiver
how does a receiver in a GPS lock onto the signal of the satellites
through triangulation
how to determine latitude without a GPS receiver
use the north star, Polaris
how to determine longitude without a GPS receiver
use time of a known longitude and time where you are
What are two time zones
- GMT
- UTC
GMT stands for
Greenwich mean time
UTC stands for
universally coordinated time
earth rotates 360 degrees in
24 hours
how many degrees does earth rotate in 1 hour
15
what is the international dateline
the separating of Monday and Sunday
true or false
the international dateline is straight
FALSE
what do these contour lines show
hill
what do these contour lines show
depression
what do these contour lines show
river valley
what do these contour lines show
ridge
what does 1 show
parallels of latitude
what does 2 show
meridians of longitude
what will the profile be
concave
what will the profile be
convex
what will the profile be
straight
Why were clocks used to calculate longitude
clocks set at GMT time would be based on high noon = position of the sun
how was longitude calculated
based on the position of the sun and the knowledge of longitude
______ is the only true representation of the Earth
Globe
globes are normally ____ scale
small
what do maps provide
a 2d representation of earth
what do the 2d representations of earth result in
distortion
what are classes of projections
- cylindrical projections
- planar projections
cylindrical projections
preserve shapes at the expense of distances
what region are stretched with cylindrical projections
polar regions
how can cylindrical projections cause confusion
size of the continents
planar projections
light source at the center of the globe projecting onto a plane
what is the result of planar projections
severe distortion GREATEST away from the origin
planar projections example
gnomonic projection
cylindrical projection example
mercator maps
remote sensing
the capturing of digital earth imaging from spatial aircrafts/satellites
remote sensing is the gaining of information from
a distance
what are two types of remote sensing
- active sensing
- passive sensing
what is an active remote sensing
the use of instruments that generate a pulse that is reflected back and then generated by a computer
what is passive remote sensing
sensing that does NOT shoot a beam
what type of remote sensing is this
records energy reflected/emitted from a surface
passive
what part of the electromagnetic spectrum does passive sensing do well in
visible spectrum
is aerial photography a form of remote sensing
YES
forms of passive remote sensing
- aerial photography
- Landsat
- quickbird
what does Landsat measure
Infrared wavelength
what does quick bird measure
- visible
- near IR
true or false
the resolution of the satellites has greatly improved
true
what are examples of active sensing
- radar
- lidar
what type of remote sensing is this
directs a beam of energy at a surface and analyze the energy that is reflected back
active
how does radar work
emits a microwave pulse that echos back
what scatters radar
percipitation
what is an example of radar being used
for weather forecast
how does lidar work
impulses from a laser
what wavelength does lidar use
ultraviolet, visible and infrared light
what is lidar used for
to measure distance
what type of active remote sensing creates 3d models
lidar
what is the similarity between active and passive remote sensing
both interpret electromagnetic information back
types of orbital paths
- geostationary orbit
- polar orbit
- near-polar sun-synchronous
what is geostationary orbit
a satellite is parked above a specific location for a fill hemispherical view
where are lots of geostationary satellites
the equator
a polar solar orbit takes
about 90 mins for a full orbit
near-polar sun-synchronous orbit shifts
1 degree every day
what orbit passes above the equator at the same local time each time
near-polar sun-synchronous
what are some applications of remote sensing
- weather forecasting
- tracking environmental problems
- landscape changes
- monitoring forest fires
weather forecasting needs sensors to
scan broad areas rather fast
remote sensing benefits
- inexpensive data
- accessible via the internet
- remote areas
- great level of detail
- repeat coverage
remote sensing limitations
- high capital cost
- training needed
- interpretation of images
- limitations of each system
GIS is a software to
organize spatial and attribute data
what is GIS used for
to create maps with multiple data layers (physical and cultural features)
types of data in a GIS
- vector and raster
vector data in GIS
lines defined by X Y cooridnates
raster data in GIS
composed of grids of cells with each cell assigned a number
what is assumed about all points in raster data
that those within the grid have all the same characteristics
