The knowledge of fixing various
coordinate systems is critical for designing maps because every map is
deceiving in its own unique way. In our first lab we are asked to look more in depth, in recognizing
the problems along with the benefits of each individual coordinate system have.
First
we are asked to add the world shape file to ArcMap and produce a particular
projection of the world. This step is repeated four times with each map requiring
a different world projection. The projections that I applied were the Mercator,
Sinusoidal, Geographic, Equidistant-Conic, and Van der Grinten I.
For this exercise the goal is to show the areas that are distorted and preserved
across the map projection. Starting with the Mercator projection; here this
projection helps preserve direction and shape, but distorts distance along with
area. Notice once you move north or south from the equator the area steadily
increases. The Mercator is a projection that is commonly used for world map. Next is the Sinusoidal, which helps preserve direction and
shape, however distorts area and distance. This projection I find the most
appealing because the viewer gets the correct impression of the relative geographic
sizes of the continents, oceans, and countries. The geographic projection helps
preserve the area and direction, but transforms the shape and distance. This
map projection is excellent for pilot navigation. The most interesting applied
projection is the Equidistant-Conic. I find this
fascinating due to of the unique North Pole perspective you observe. Here we see maintained distance and area, but alters the direction and shape.
My final projection I choose is the Van der Grinten I. I
picked this projection because I thought the name was amusing and I also found
out that the map projection shares the same characteristics as the Mercator
projection. I find this better than the Mercator because
I like how the cartographer constructed circular arcs for both meridians making
its data on a global scale.
After
applying the five world projections I proceeded to make my own map projection of the
United States of America and the state of Wisconsin. Here I used
the U.S. was the GCS (geographic coordinate system) North America 1983
projection. Once the U.S. shapefile was established I then proceeded to
add and fix the Michigan roads shapefile. As a result the projection reflected
the overlay of the two shape files calling this an “On the fly projection.” The
objective for Wisconsin is to change its projection to UTM,
NAD 1983, Zone 16N. Where this helps keep distortion
to a minimal. After completion of the two map projections we were obligated to
join the five previous projections with the two recently applied
projections onto one document. The finished product is shown in figure 1.
The
last exercise performed involved “On the fly projection.” This time
the projection included the central Wisconsin counties and the present river ways.
This exercise also implicated us to fix the coordinate system so the two
different shape files could be compatible with each other. When come to
completing the lesson I am asked again to fit the projection onto one
document (figure 2) while having to add a legend, neat line, north arrow, and a
scale.
Finally
the lab is complete. I can now evaluate various projected coordinate systems
and can apply them to GIS data. In addition I can identify projection errors in
GIS data, project the data appropriately so that they can be used in a GIS.
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| Figure 1 |
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| Figure 2 |
