Map Projections - Spatial Mathematics: Theory and Practice through Mapping - page 209

9.11 Exercises
9.11.1 Overview
This section outlines two exercises in detail and suggests a few hints for
solution to get the reader started on the right track. To see the detailed solu-
tions, consult the associated Solutions Manual. These exercises are designed
with the reader in mind who has access to high-end software and computing
equipment. Following them, a set of links only to some existing online exer-
cises offers further challenges to the reader.
9.11.2 Comparing projections with ArcGIS for desktop
In previous material in this chapter, you used a web-based GIS to com-
pare data sets mapped onto three different projections. These map pro-
jections were already set up, and you used them to analyze how different
data appears mapped on these projections. In this exercise, you have the
opportunity to change the map projections. As this is an even more power-
ful technique, you need a more powerful set of tools to accomplish it, which
are found within ArcGIS for Desktop software. You will examine the shape
of countries, plate tectonics, and the world graticule in unprojected space, in
the Eckert IV projection, in the Robinson projection, and in the Mollweide
projection.
Go to ArcGIS Online ( http://www.arcgis.com/home ) and, after making sure
that your search criteria are set to “all content” instead of “web content only,”
search for the following data: “World Earthquakes Volcanoes Faults Countries
Plate Polys Elevation owner:jjkerski.” This is a map package, which contains
all the data you need to explore projections in a rigorous way. Under the
thumbnail image, select “open in ArcGIS for Desktop.” Once the map opens,
click the globe tool to zoom to the extent of the map. Turn off the eleva-
tion image to get a clearer view of the countries. Select “View → Data Frame
Properties” and then “Coordinate System” to check the map's current projec-
tion. Note that it is listed as “geographic, world, WGS 84.” The map is not in
a projected coordinate space; it is a latitude-longitude representation of data
in a “geographic” coordinate space. Examine the shape of the countries on
the map. What is a disadvantage of this geographic coordinate space view
in terms of the shape of countries near the North Pole and the South Pole?
In light of what you have learned in this topic, what are some of the dan-
gers inherent in using data in this geographic coordinate space? The issue of
spreading or compression of the graticule near the poles is a significant one
that can impact the visualization of data.
Use the Add button to Add Data from ArcGIS Online. Search ArcGIS Online
for “Grid” and add the “World Latitude and Longitude Grids” layer. This is the
1 degree grid for the world. Describe the latitude and longitude lines as they