Lab 6: Digital Elevation Models in GIS

                The area that I have chosen for my digital elevation model is located around the Lower Pitt-Taylor Reservoir in Nevada. The frame that was used has the coordinates: 39.8452 for the top edge, 39.4416 for the bottom, -118.3163 for the left, and -117.74083 for the right edge. This map was created referencing the North American Datum of 1983. The DEM shows the elevation of the mountainous terrain as well as the slope and aspect of the terrain. The aspect shows the steepness of the given surface area. The lab also shows a 3D model of the terrain which helps visualize the terrain instead of seeing it on a flat 2-D surface.

                Being able to see the different gradients of the DEM made it easier to see the elevation for the terrain as well as the slope surface of it. By exploring the different features of the program, I was able to learn about the surface of the area I chose.

Lab 5: Projections in ArcGIS

Using projections is an efficient way to visualize the earth. Since the earth is a sphere, it is difficult to observe it unless it is projected in a way that lets us see it as a plane. Thus, we must distort the earth in different shapes and sizes which ultimately distorts its true distances and areas. The true shape of the earth as well as its continents are not going to be retained and thus, they will be skewed in different way. The different types of projections that we observe in this lab are: Conformal, Equal Area and Equidistant.
Conformal maps keep the latitude and longitude lines at angles instead of curving them as seen in the first two map projections. Area and distance are not retained in these map projections however. As seen in the Mercator map, areas further from the equator are stretched and are more distorted due to its cylindrical projection. It is best used for projection.
Equal area map projections are able to preserve the actual area of land on these projections. For both the sinusoidal and the Bonne map projection, the areas of the continents are equal in size to their actual land mass. However, the areas away from the central point are much more distorted such as in the Bonne map projection, Africa seems to be the least distorted as it in the center focus of the map projection.
Equidistant map projections preserve distance. It portrays the distance from the center of the map to other place on the map. These maps are used for radio and seismic mapping. The equidistant cylindrical map projection have equally spaced longitudes and latitude lines.
Map projections should be selected based on what you are observing on the map projections. Different map projections are more catered to specific purposes such as certain continents are different navigational purposes. There are some projections that are created to observe certain areas and distances. Such as observing the distance from two cities, different map projections will show a different area where some are more accurate than others.

Lab 4 - Introducing ArcMap

 

By using GIS features, we are able to explore the different layers of a proposed map based on particular interests. In this particular lab assignment, we are able to view the different maps of a proposed airport expansion based on the Land Use, Schools, and Population Density of the same area within the same map layout. This allows up to simultaneously explore different aspects of an area without the congestion of information on a single map by being able to hide and show layers with ease.

This system is beneficial in allowing different methods and possibilities in map construction with ArcGIS. The fact that it is computer generated allows precision and accuracy in viewing these maps without too much interference of human error. With the available data and accessibility of the programs, anyone is able to create maps of whatever they need in order to fit their specific needs. Any calculations and measurements are handled with the operating systems that makes it easier to create these digital maps.

The downfall is the difficulty in creating these maps with ArcGIS. There are many different components and functions to do and learn that it becomes complicating if one is not familiar with the program. In creating these maps with ArcGIS, I ran into difficulties by clicking incorrect buttons or not understanding the terminology. The data must also be organized so that the software can understand the data you are inputting into the system.

Though it is difficult, this program is beneficial to learn because creating these types of maps can help in all sorts of research. With this program, we are able to learn about different areas and all the sorts of features that it possesses. Moreover, we are able to present the data in a graphic form to inform other of the findings.