Lab 3 submission
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School
University of Waterloo *
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Course
181
Subject
Geography
Date
Dec 6, 2023
Type
Pages
4
Uploaded by AdmiralLark3870
1)
Map
CRS name and EPSG ID
CRS type (geographic, or
projected)
Geometric relationship(s)
preserved
WGS 84 (EPSG:4326)
Geographic
None
World_Azimuthal_Equidistant
(EPSG:54032)
Projected
Distance, direction
World_Mollweide (EPSG:54009)
Projected
area
WGS 84 / Pseudo Mercator
(EPSG:3857)
Projected
Direction, Shape
World_Robinson (EPSG:54030)
Projected
none
2)a)
World Mollweide (EPSG:54009) vs WGS 84/ Pseudo Mercator
(EPSG:3857) projection
When comparing the two projections, a difference that is immediately noticed is that the polar regions are much more distorted in the
Pseudo Mercator projection, as they are shown with a distorted area, while the World Mollweide projection appears to display its area more
accurately. This can also be seen by analyzing the Tissot circles, the Mercator projection shows the circles increasing in size the further they are
from the standard line/equator, while the Mollweide projection shows all the circles having a similar area. By observing the Tissot circles of the
Mollweide projection, it can also be seen that there is distortion in the shape as they approach the poles. In comparison, the Mercator
projection has little to no distortions in shape.
When observing the graticule lines of the Mollweide projection the longitude lines come to a point at both poles, whereas the Mercator
projection
’
s lines are parallel and do not come to a point. Mollweide
’
s lines show that distance, shape and direction get more distorted as you
get closer to the edges while points around the center have little distortion, compared to the Mercator projection whose lines do not come to a
point while being straight and parallel, meaning the shape and direction are preserved throughout the map.
b) deforestation around the globe over the past 10 years
I would choose the Mollweide projection. When showing deforestation, the most important geometric relationship to preserve is the
area of land so that the area of deforestation can be clearly seen with little distortions. Even though the shape, direction and distance in a
Mollweide projection are distorted it doesn
’
t matter as much as area. If deforestation was only being shown at a specific point in the map, then
a different projection could be chosen that would preserve more than just area, however, since it is global the area on all parts of the map must
be preserved. Most of the map has little distortions and only increases when going towards the poles, this is useful as a majority of deforestation
does not occur at the poles, this means that a majority of deforestation displayed will have less distortions.
3)a)North_America_Lambert_Conformal_Conic (ESRI:102009)
I chose this map as it preserves the shape and direction which are geometric relationships important for understanding
the location of the bears in North America. Area is also relatively less distorted around the region despite distorting as it
goes further from the center.
b) North_America_Albers_Equal_Area_Conic(ESRI:102008)
I chose this projection as it maintains area and direction. The most important geometric relationships to preserve for this
data are the area and distance as it will allow the viewer to accurately understand the extent of the infestation and where
it is occurring.
c) US National Atlas Equal Area(EPSG:2163)
I chose this map projection as it is centered around North America and has little distortion in that region. It preserves area
and relative distance from the center, and even if the areas further from North America are distorted it doesn
’t matter as
the data is only in North America. Shape is also only slightly distorted around that region. The area is the most important
geometric relationship as it is used to accurately compare the unemployment rates between regions.
d)Distance direction
North_Pole_Lambert_Azimuthal_Equal_Area(ESRI:102017)
This map projection was chosen as it preserves the size and direction geometric relationships. These are important to
preserve so that they can be used to accurately gauge the distance of the and location of the routes. Shape and size is also
less distorted around the north pole so it is easier to understand the map.
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4) EPSG:26917
EPSG:4326
EPSG:3857
When changing the CRS to ESPG:4326 the building corners are no longer at right angles and are more narrow or wide, it appears as if the
building was squashed vertically. In ESPG:4326, the buildings appear to have right angled corners as the co ordinate system used was designed
to minimize distortions in shape at that specific zone, after switching to another CRS the buildings appear squashed as it was not designed to
preserve the shape at that location. This change is likely linked to the location being further away from the equator as the distortion appears
visually similar to the Tissot circles in other maps where the further they were from the equator the more distorted they appeared.
When switching the CRS to EPSG:3867 the corners of the buildings appear to be square again, however, the size appears to have changed. From
this we can infer that this CRS was designed to preserve shape but not preserve area.