GEOG 181-Lab 3 (1)
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University of Waterloo *
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Course
181
Subject
Geography
Date
Dec 6, 2023
Type
Pages
4
Uploaded by CaptainBoulderMouse32
Likhitha Tananki ~ 21012570
October 1st 2023
GEOG 181-Lab 3
1.
Create a new QGIS project and add these shapefiles:
●
Ne_110m_admin_0_countries,
●
Ne_110m_graticules_15,
●
Tissot30
Map
CRS name and EPSG ID
CRS type
(geographic, or
projected)
Geometric
relationship(s)
preserved
WGS 84 (EPSG:4326)
Geographic
Area
World_Azimuthal_Equidistant
(EPSG:54032)
Projected
Preserves
Direction
World_Mollweide
(EPSG:54009)
Projected
Preserves Area
WGS 84 / Pseudo Mercator
(EPSG:3857)
Projected
Preserves Shapes
World_Robinson
(EPSG:54030)
Projected
None
2.
Re-examine the five projections you added to the table in Task 1.
a.
Compare the World Mollweide (EPSG:54009) projection with the WGS 84/
Pseudo Mercator (EPSG:3857) projection. Compare and contrast the
pattern of distortion in these two projections. How do the Tissot circles
change as you move away from the standard line? (4 marks)
The World Mollweide is an Equal-area projection in which the Tissot circles mostly stay the
same, however, the circles become very distorted once they are near the North and South
Poles. This exemplifies how a map can preserve areas in its geometric relationships. However,
the Pseudo Mercator Projection is a Conformal Projection where the Tissot Circles increase in
size as you stray from the standard line. This exemplifies how a map can preserve shapes in its
geometric relationships.
b.
Of the five projections shown in the table from Task 1, which one would
you choose for a map showing the areas of deforestation around the globe
over the past 10 years? Why would choose that particular projection? (3
marks).
I would choose the World Mollweide Projection(EPSG:54009) as it identifies the areas that have
deforestation around the globe more accurately while preserving the size of the areas in
comparison to the shape, distance or direction.
3.
In addition to the five projections we explored above, a wide variety of other
projections can be used for various applications. Take time to explore some
others. Explain which map projection would be appropriate for each of the
following maps and why. (8 marks):
a.
A dot map of the grizzly bear population in North America
North America Equidistant Conic ESRI:102010
The Equidistant Conic Projection preserves the distances along a set of
meridians and two standard parallels. This is helpful when making a dot map of
the grizzly bear population in North America, as there’s an accurate
representation of the area when calculating the population.
b.
A map showing areas of pine beetle infestation in North America
North America Equidistant Conic ESRI:102010
The Equidistant Conic Projection preserves the distances along a set of
meridians and two standard parallels. This is helpful when making a map
showing areas of pine beetle infestation in North America, as there’s an accurate
representation of the area when calculating the areas of infestation.
c.
A map showing state and provincial unemployment rates in North America
North America Equidistant Conic ESRI:102010
The Equidistant Conic Projection preserves the distances along a set of
meridians and two standard parallels. This is helpful when making a map
showing state and provincial unemployment rates in North America, as there’s an
accurate representation of the area when calculating the unemployment rates
within states and provinces. There would be an accurate measurement of
distances and areas.
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d.
Airline routes across the northern polar region
North Pole Azimuthal Equidistant ESRI:102016
The Azimuthal Equidistant Projection preserves the distance from the centre
(Azimuthal) to all other points on the map. This allows the map user to clearly
identify the airline routes across the northern polar region.
4.
Create a new QGIS project and add the hd_buildings shapefile from assignment 1.
By default, the features will be added in EPSG:26917 (the coordinate reference
system (CRS) in which the shapefile features are stored). Zoom in to a small part
of one of the heritage districts. Notice that the corners of the buildings appear to
be right angles (as you would expect). Now change the CRS to EPSG:4326. How
do the buildings' corners appear now? Can you explain why the corners of the
building no longer appear to be square? Now try EPSG:3857. Are the corners still
square now? Include an exported image of the buildings in each of the three CRSs
with your answer. (5 marks)
EPSG:26917
EPSG:4326
EPSG:3857
In EPSG:26917 the corners of the buildings are right-angles. However, in EPSG:4326 the
corners are more angled than the other two maps. ESPG: 4326 is a coordinate system that
represents Earth as a three-dimensional ellipsoid. The map is not projected, but Geographic, as
such it doesn't have the distortion issues of the Web Mercator. The corners in EPSG:3857 are
square.