Module 2 - Coordinate Systems
Utilizing the correct coordinate systems and projections is a crucial skill in creating accurate maps that reduce deformities and portray the globe's true properties. This laboratory assignment involved creating a variety of maps, selecting the best coordinate systems / projections, and analyzing the impacts of deformities on a map due to projections.
I chose to assess the state of Vermont as my area of interest. The coordinate system I chose to implement for Vermont was NAD 1983 (2011) StatePlane Vermont FIPS 4400, because this system proved to be the most accurate and resulted in the least distortion for the map area. The other options available were less appropriate because State Planes are the most accurate, compared to UTM and other projections, as they are tailored to their specific states. Since the state of Vermont only lies in one state plane, this meant that it was appropriate to use the State Plane projection.
I chose to assess the state of Vermont as my area of interest. The coordinate system I chose to implement for Vermont was NAD 1983 (2011) StatePlane Vermont FIPS 4400, because this system proved to be the most accurate and resulted in the least distortion for the map area. The other options available were less appropriate because State Planes are the most accurate, compared to UTM and other projections, as they are tailored to their specific states. Since the state of Vermont only lies in one state plane, this meant that it was appropriate to use the State Plane projection.
I was tasked with altering projections on a world map and assessing how the different projections chosen distorted the maps and which was the best at portraying our Earth on a 2D map form. Below are some examples of how I analyzed the projections' impacts on the global maps.
The Mercator projection is one that I have many qualms with due to its extreme distortion near the poles. This distortion makes the land masses in/near the poles seem much longer than they actually are, and shrinks land masses near the equator (i.e. Central America and Africa). This projection is fairly common on 2D sources, but is unfortunately extremely inaccurate and distorted. Higher (absolute) latitudes have higher magnitudes of distortion within the Mercator projection. This is known because the cities located at higher (absolute) latitudes have greater differences between their planar and geodesic distances. Gerhardus Mercator created this projection knowing that longitudinal lines converge at the poles, and thus chose to increase latitude towards these regions, to keep the lines straight, thus increasing distortion at higher latitudes (Buckley, Kimerling, Muehrcke, and Muehrcke, 2016). Due to the warping of the spherical globe into a flat, rectangular map, this causes the distances/areas at higher latitudes (those further from the equator), to be much larger than they actually are in reality. Thus, the distances may appear larger when measuring from a planar, or flat, perspective. When measuring with a curved, geodesic perspective, this will show that the distances are not as great as they appear on the map.
Another common projection, the Robinson does a better job at reducing distortions. It is a pseudocylindrical projection, implementing elements from equal area and conformal projections (Buckley, Kimerling, Muehrcke, and Muehrcke, 2016). However, the process of transferring a sphere to a 2D map has its challenges, as one may see the elongation of the circles near the poles. This means there is distortion occurring there, as the top and bottom of the map are not true to their real counterparts.
The Equal Earth projection is very similar to the Robinson, but has a few minor differences that change the appearance of certain areas. An example would be the land masses near the equator are larger in this projection, being more accurate to their real counterparts. However, one may notice how the poles’ circles are much smaller than the rest of those on the map, indicating distortion is still occurring there.
The Patterson projection excels in reducing distortion and displaying land masses to their accurate sizes. Considering how well it does so while maintaining a rectangular shape is notable. One may notice that the circles are slightly longer in some rows, but overall the distortion is minimal in this projection, especially considering how lines of latitude and longitude are straight and not curved.
Coordinate System Details Captured in ESRI's ArcGIS Pro
Semimajor Axis 6378137.0
Semiminor Axis 6356752.314140356
Mercator Projection
The Mercator projection is one that I have many qualms with due to its extreme distortion near the poles. This distortion makes the land masses in/near the poles seem much longer than they actually are, and shrinks land masses near the equator (i.e. Central America and Africa). This projection is fairly common on 2D sources, but is unfortunately extremely inaccurate and distorted. Higher (absolute) latitudes have higher magnitudes of distortion within the Mercator projection. This is known because the cities located at higher (absolute) latitudes have greater differences between their planar and geodesic distances. Gerhardus Mercator created this projection knowing that longitudinal lines converge at the poles, and thus chose to increase latitude towards these regions, to keep the lines straight, thus increasing distortion at higher latitudes (Buckley, Kimerling, Muehrcke, and Muehrcke, 2016). Due to the warping of the spherical globe into a flat, rectangular map, this causes the distances/areas at higher latitudes (those further from the equator), to be much larger than they actually are in reality. Thus, the distances may appear larger when measuring from a planar, or flat, perspective. When measuring with a curved, geodesic perspective, this will show that the distances are not as great as they appear on the map.
Robinson Projection
Another common projection, the Robinson does a better job at reducing distortions. It is a pseudocylindrical projection, implementing elements from equal area and conformal projections (Buckley, Kimerling, Muehrcke, and Muehrcke, 2016). However, the process of transferring a sphere to a 2D map has its challenges, as one may see the elongation of the circles near the poles. This means there is distortion occurring there, as the top and bottom of the map are not true to their real counterparts.
Equal Earth Projection
The Equal Earth projection is very similar to the Robinson, but has a few minor differences that change the appearance of certain areas. An example would be the land masses near the equator are larger in this projection, being more accurate to their real counterparts. However, one may notice how the poles’ circles are much smaller than the rest of those on the map, indicating distortion is still occurring there.
Patterson Projection
The Patterson projection excels in reducing distortion and displaying land masses to their accurate sizes. Considering how well it does so while maintaining a rectangular shape is notable. One may notice that the circles are slightly longer in some rows, but overall the distortion is minimal in this projection, especially considering how lines of latitude and longitude are straight and not curved.
Canada in Lambert Conformal Conical Projection
Coordinate System Details Captured in ESRI's ArcGIS Pro
Projected Coordinate System NAD 1983 CSRS UTM Zone 10N
Projection Transverse Mercator
WKID 3157
Authority EPSG
Linear Unit Meters (1.0)
False Easting 500000.0
False Northing 0.0
Central Meridian -123.0
Scale Factor 0.9996
Latitude Of Origin 0.0
Geographic Coordinate System NAD 1983 (CSRS)
WKID 4617
Previous WKID 4140
Authority EPSG
Angular Unit Degree (0.0174532925199433)
Prime Meridian Greenwich (0.0)
Datum D North American 1983 CSRS
Spheroid GRS 1980
Projection Transverse Mercator
WKID 3157
Authority EPSG
Linear Unit Meters (1.0)
False Easting 500000.0
False Northing 0.0
Central Meridian -123.0
Scale Factor 0.9996
Latitude Of Origin 0.0
Geographic Coordinate System NAD 1983 (CSRS)
WKID 4617
Previous WKID 4140
Authority EPSG
Angular Unit Degree (0.0174532925199433)
Prime Meridian Greenwich (0.0)
Datum D North American 1983 CSRS
Spheroid GRS 1980
Semimajor Axis 6378137.0
Semiminor Axis 6356752.314140356
Inverse Flattening 298.257222101
The NAD 1983 CSRS UTM Zone 10N Projection contains the following characteristics
Geodetic Datum - NAD 1983 CSRS (Canadian Spatial Reference System)
British Columbia with NAD 1983 CSRS UTM Zone 10N Projection
The NAD 1983 CSRS UTM Zone 10N Projection contains the following characteristics
Geodetic Datum - NAD 1983 CSRS (Canadian Spatial Reference System)
Family - Cylindrical
Type - Transverse Mercator
Type - Transverse Mercator