Week 8 Lab

             

            The first map shows the percentage of the Black population compared to the total population by county.  The map is interesting because it shows that compared to the total population of the county, the highest concentrations of blacks is in the southeast.  This may be expected due to the historical slave trade which tragically brought many Blacks from Africa to the east coast.

            The second map shows percentage of the Asian populations compared to the total population by county.  This map also shows the interesting trend that the Asian population is most concentrated on the east coast.  This may be due to the historical event of the gold rush.  During the gold rush many Asians sought fortune on the west coast in the form of gold.

            The third map shows percentage of some other race alone compared to the total population by county.  This map shows that this race is concentrated in the southwest and southern parts of Texas.  I’m not exactly sure what race this is referring to, so it would be interesting to do some research and find out which race is being plotted on this map.

            Working with census data has been extremely interesting and fun.  It was actually quite easy to produce these maps.  Despite the ease with which they were produced, they are extremely useful.  The maps are much easier to interpret than the excel files which they were downloaded in.  Just by looking at the map, you can very quickly determine where the populations are most concentrated.  This exercise shows just how great of a tool GIS can be.  It can take huge tables of data which would be very difficult to analyze, and turn it into an easily interpretable product. 

Lab 6

Iconic Half-Dome Rock in Yosemite

    I made my map of Yosemite National Park, which is located in California’s western Sierra Nevadas.  Yosemite is home to some of the most beautiful scenery in the country.  I chose to make my map of Yosemite because I am interested in its geology.  Virtually all of the rocks in Yosemite are granitic rocks which were formed by magma which cooled beneath the earth’s surface.  The spectacular forms of the rocks were formed due to glaciers sliding over the rock and sculpting amazing features.  Yosemite is a great place to study if you are interested in geology.  It is also great for rock climbing, sight seeing, and just enjoying the great outdoors.  The extent of my map is N: 37.93918, W: -119.75873, S: 37.56238, E: -119.36309.  The spatial reference was GCS North American 1983. 

Lab 5

                Map projections are an extremely important aspect of GIS.  In order to represent the earth, which is a sphere, in a two-dimensional matter map projections must be used.  When trying to display the earth on a two-dimensional plane, deformation is inevitable.  Depending on which projection you use, different aspects of the earth will be deformed.  Depending on what you want your map to portray there will be a certain projection that will preserve the dimension which will best suit your map.  The three projections we used in this lab were equal area, equidistant, and conformal.

                Equal area map projections preserve the areas of the earth.  This type of projection can be useful when you want to show the actual sizes of landmasses relative to each other.  For example, if you were to look at a Mercator map, you would think that Greenland is a very large country relative to other landmasses, when in reality its size is much smaller.  When you use an equal area map projection such as sinusoidal or bonne projections  you can really see the continents’ actual sizes relative to each.

                Equidistant map projections preserve distance from a defined point or line.  The Plate Carree map projection preserves distance from the equator.  This map projection is appealing because it portrays the earth as a very simple rectangular map.  The two point equidistant projection sets two points and the distance to these points from any point on the map is preserved.

                Conformal map projections preserve local shapes and angles.  These maps are most accurate at a local scale.  The stereographic map preserves the shapes of circles.  The hotine projection is another conformal projection.  These projections would be useful for navigation in a localized sense.

                As you can see by looking at the distances measured between Washington D.C. and Kabul they change.  Obviously in reality the distance will always be the same, however the fact that these distances were measured on different projections caused them to be different.