Week 8: Census Maps

Number of People, 2000: This map is a graphic image of the populations within the different counties on the continental United States in 2000. The population scale is represented by a descending shade of purple: the darkest purple represents the most populated counties while the lightest purple represents the last populated counties. As illustrated on the map, the highest populations live on the west side or on the east side of the country. The middle is the least populated part of the country, with most counties having a population between 107 and 9999 people. The most populated counties often contain the largest cities in the nation, which is logically feasible.

Difference, 1990 to 2000 Number of People: This map displays the changes in population that occurred in each county within the continental United States between the years 1990 and 2000. The color scale goes from dark green to a bright fuchsia color: the dark green being the largest gain in population and the fuchsia representing the largest loss in population. All the pinkish hues signify that there was a loss in population in the ten years and all the greenish hues denote that there were gains in the population within that time period. Similar to the previous graph, the highest numbers were near the big cities on the opposing coasts. It is interesting to note that the places that underwent the greatest increases in population also were the most populated areas at the end of the ten year period. This means that these areas are consistently increasing their populations over time.

Percent Change, 1990 to 2000 Total Population: This map illustrates the percent change in population within the counties in the continental United States of America. The color scale goes from dark purple to a bright gold-yellow: the dark purple being the greatest positive percent change in population and the gold-yellow representing the greatest negative percent change in population. The purple hues represent as the positive percentages, or the increasing number of population. The yellow hues signify the negative percentages, or the decreasing number of population over the time of the ten years. The patterns in this graph are slightly different from the previous two. There are higher changes in percent in the Mid-west (such as Nevada and Arizona) than the coasts. This means that these counties’ populations have increased the most in the past 10 years.

Population Density, 2000: This map displays the density of population in the counties of the continental United States. Density illustrates the concentration of people living in a certain measure of area. The color scale represent the decreasing density within the counties. The darkest blue signifies the highest density with the lowest density illustrated by the near white color. The scale goes from the darkest blue to lighter blue to green hues to off white. Not unexpectedly, the highest density counties are those that contain the biggest cities. This means that the people of the densely populated county live in closer proximity to each other than those that live in less densely populated counties. The denser populations mean that there are more people per square measurement of the county.

The census map series is a useful tool to see the changes over time of population growth. It provides a clear demonstration of the population of 2000, the difference over the ten years between 1990 and 2000, the percent change of total population over those ten years, and the population density in 2000. Overall, the exercise with the census data was very interesting and was a clear demonstration of the different uses of the features of maps. Color, labeling, and organization are all important in order to create an aesthetically pleasing, informative map easy for anyone to see and understand the purpose of it. This exercise with ArcGIS was a good introduction to try and build knowledge and experience with cartography. This program would be easier to navigate if there was a search engine for the system to find certain tools but overall it is a fairly easy system to work once the user knows where all the utilities are located. 

Week 7: DEMs in ArcGIS

The area, which was examined in this lab, was a region in Colorado in the United States. The extent was 39.8291666661 decimal degrees at the top, 39.3838888883 decimal degrees at the bottom, -105.788888889 decimal degrees at the left, and -104.969444445 decimal degrees at the right. The geographic coordinate system that was used was the North American GCS of 1983 (GCS_North_American_1983). The area in Colorado mostly consists of the Arapaho National Forest just west of the city of Denver. In the three-dimensional image, the elevation is shown to be inconsistent, therefore indicating that the area is most likely mountainous. The aspect model indicates that there is a variance in which way the features face, whether north, south, east, or west. The slope model indicates how steep or shallow the slope of a feature is. 

Week 6: Projection in ArcGIS

Miller Cylindrical Projection Distance between Washington D.C. and Kabul: 10,131.25181394 miles

Mercator Projection Distance between Washington D.C. and Kabul: 10,112.13919192 miles

Eckert IV Projection Distance between Washington D.C. and Kabul: 7,835.043849347 miles

Mollweide Projection Distance between Washington D.C. and Kabul: 7,925.573197180 miles

Equidistant Conic Projection Distance between Washington D.C. and Kabul: 6,972.494037703 miles

Equidistant Cylindrical Projection Distance between Washington D.C. and Kabul: 5,061.88690287 miles

         Map projections are a tool geographers use to transform the 3-dimensional globe into a 2-dimensional form. It is a process of mathematical conversion in which the “real” measurements of the Earth must be translated into “virtual” measurements. The three methods of projections are planar or azimuthal, cylindrical, or conic. The simplest way to demonstrate the process of using these methods to make projections is to compare it to translating the globe onto a piece of paper. The planar projection is when a piece of paper is held up to one part of the globe and the part where the paper touches is extremely accurate but the regions that do not touch are distorted. The cylindrical projection can be described as wrapping a piece of paper around the globe in the shape of a cylinder. Wherever the map touches the globe, the map is accurate but the regions above and below the touching paper would be distorted. Lastly, the conic projection can be described as wrapping and folding a piece of paper into a cone shape and putting it around the globe like a hat depending on the angle in which it is held up to the Earth. Three types of map projections that use these methods are conformal, equidistant, and equal area.

           A conformal map projection is when the meridians and parallels intersect at right angles. Another characteristic of the conformal map is that the scale at any point must be the same in all directions. They preserve local shapes and angles; however they distort the areas rather significantly as demonstrated above in the Mercator projection and the Miller Cylindrical projection. This is clearly exhibited by the comparison of the distance between two points, or cities, as displayed on the maps. The two points represent Washington D.C. in the United States and Kabul in Afghanistan. The distance as represented on the Mercator projection shows it as approximately 10, 112 miles. However, on the Miller Cylinder projection the distance between the cities is stated as approximately 10,131 miles. This is not an excessive distance comparing between the two conformal maps, but when comparing it to other types of projections, there is a significant discrepancy.

            An equal area projection maintains the same proportional relationships to the areas on the Earth that they represent. This means that the area of North America is displayed proportionally accurate in comparison to the areas of Africa and Europe. Examples of the equal area projection are displayed above in the Mollweide and Eckert IV projections. However, the distance between two points is not necessarily maintained in the equal area map projection, as displayed in the distance between Washington D.C. and Kabul. The distance on the Mollweide map projection is measured as around 7,926 miles. On the Eckert IV projection, the distance between the two cities is calculated as about 7,835 miles. Again, there is not an extreme difference between the distances comparing the two types of equal area projections, a mere 91 miles. However, when comparing these distances to other map projections, such as the conformal map projections, the difference could be over a few thousand miles.

            Another type commonly used is the equidistant map projection. The equidistant map projection is a projection that maintains scale from one or two points to all other points on the map. This means that, with the correct scale, the distance between two points is proportionally accurate. Examples of the equidistant map projection are displayed above in the Equidistant Conic projection and the Equidistant Cylindrical projection. The distance between Washington D.C. and Kabul on the Equidistant Cylindrical projection is measured as about 5,062 miles. On the Equidistant Conic projection, the distance between the two cities is measured as around 6,972 miles. The “real” distance between Kabul and Washington D.C. is stated to be around 6,920 miles. (There are different resources that have different exact measurements.) The Equidistant Conic projection seems to have the most accurate scale out of all the map projections to measure the distance between Kabul and Washington D.C. The equidistant projection has significantly different calculations to the distance between the two points compared to the conformal and equal area map projections. These examples and relationships display the importance of using a specific type of map projection in order to convey the information accurately, as according to the creator, to the audience.

Week 4 & 5: ArcGIS

           As this was my first time using ArcGIS, I had a certain level of apprehension, as I am not a very technical savvy person. Also, I have no background in any knowledge about creating maps or very much about geography in general. Approaching this project, I knew I was going to entering into an entirely new field where I was going to learn a very different set of useful skills. The pre-lab information available gave me a fairly good idea of the type of programming steps I would be taking but I had no idea what the structure of that program would be.

            Opening up ArcGIS and the data from the course website was very simple and easy to use. The instructions were very direct and explicit, which made the process less intimidating. However, the instructions were for a less updated version, so sometimes it was slightly confusing on what change and what functions I needed to use. That is one of the disadvantages of ArcGIS: it is an ever-changing program that has updates to the newest information, and therefore, it is very complex in making sure all the instructions are for the particular version of the program. Also, due to all these complex steps, keeping track of all the information and data can be confusing. One of the unclear features of the program was the map scale. The textual instructions did not always match the visual aids in the sense that the map scales appeared to be different. Nevertheless, the ArcGIS program was fairly easy to navigate around.

            The program ArcGIS is an extremely useful tool to portray spatial data and explore the field of geography. The map reflects the maker’s bias and interests, which can be an advantage and disadvantage. This lab helped me explore the options that can be inserted onto a map, whether it is the amount of data included on any given layer, the organization of that data within the layers, or the organization of the individual layers. The map features are very distinct and easily recognizable, as well as customizable. Each part of the map can be divided up into data frames that represent the “layers” of the map. The ArcGIS is a very interesting way to view the boundaries of designated territories.

            Overall, ArcGIS is a very useful tool to create maps and organize data in a visual form. It is easy to use as long as there are clear instructions to the features of the map. Or, if you have experience with that type of programming, it is a fairly simple structured system that is user friendly. Once used enough, I believe I will be able to navigate my way through the basic programming of ArcGIS and make my own maps. The only downside to ArcGIS is that it is not transparent in the fact that it is not clear how the program is built up so, if necessary and you are capable, you can take shorter steps to create the same map.