Steed – Week 2

Chapter 1

This chapter introduced readers to GIS analysis, the manners in which it can be applied, and the technical terms used to describe its functions. First, the author provided a clear definition of GIS analysis, and then described the five ways in which geographic data should be analyzed: (1) frame the question, (2) understand your data, (3) choose a method, (4) process the data, and (5) look at the results. Next, Mitchell distinguishes the various feature types, which includes discrete, continuous, and summarized features. These are important because they determine how to move forward with the given data (e.g., if we know our boundaries are discrete, then we know exactly where to pull our data points). Then, the author describes how each geographic feature can be modeled—through either vector or raster models. In addition, Mitchell defines map projections and coordinate systems, and explains how the shape of our globe impacts their applications. Finally, this chapter describes different attributes that characterizes data (e.g., categories, ranks, ratios, etc.).

Overall, I think this chapter was critical in understanding some of the jargon that has been used in the past here at Ohio Wesleyan that I have neglected to do more research about. Although the information in this chapter is definitely basic, I think by starting out with this advice with accompanying examples, I will find it easier to understand the ArcGIS application.

Chapter 2

This chapter explains the importance of mapping and discloses strategies that can be utilized to best represent data through map design. First, the author specifies that mapping can be used to analyze where action needs to occur in a geographic space, to explore the causation of (an) event(s), or to search an area for a specific criterion. Then, Mitchell mentions the necessary steps to prepare data for mapping. He stated that users need to ensure that geographic coordinates and category values (if needed) are assigned to each feature. If not, Mitchell indicates that there a variety of issues that could occur. Next, Mitchell articulates how GIS works in creating a map for both single and categorical features that are prescribed by the users. In addition, the author provides tips for users to make their map as clear as possible to audiences. Finally, Mitchell discusses how to analyze geographic maps to look for patterns. He clarifies that pattern formation is one of the critical pieces of creating a map, so it is important that these steps are followed successfully.

As suspected, this chapter added to what we just learned from the first chapter. For example, Mitchell consistently reverberates terms such as “continuous” and “raster,” which were just defined in the first chapter. Additionally, this section gave great guidance to avoid mistakes when creating maps. For example, he said “if you’re showing several categories on a single map, you’ll want to display no more than seven categories,” and also, “if the pattern are complex or the features are close together, creating a separate map for each category can make patterns within a particular category—and even across categories—easier to see.” Not only will these tips allow me to avoid making unnecessary mistakes, but also it creates a better understanding of why there are specific tasks that users need to make.

Chapter 3

This chapter focused on mapping intervals of values and explained which methods of mapping are necessary based on the type of feature. First, the author examined the importance of graphing maps with varying quantities and reverberated some of the information that was discussed in chapters 1 and 2 (specifically, discrete, continuous, and summarized features). Next, Mitchell defined the various quantities like counts and amounts, ratios and ranks. Then, he begins to explain how these quantities can be divided into classes either manually or through the use of classification schemes. The four classification schemes he describes are natural breaks (jenks), quantile, equal interval, and standard deviation. Each of these class separation tools allow for geographers to better understand given data sets, but they must be used in the right manner. For example, natural breaks are good for mapping uneven data sets, but quantiles are not (they are known for comparing areas that are roughly the same size). Furthermore, Mitchell explains how to deal with outliers in data sets and defines the differences between various map types for understanding discrete, continuous, or summarized areas. Finally, the author describes how users should be able to visualize patterns in their maps, and how to make it clearer for their audiences.

Although this reading bares some similarities between chapters 1 and 2, the author was able to provide guidance for why and how classes should be assembled for a given data set. In addition, it was able to differentiate between different map types, which is useful for when I apply this knowledge to the ArcGIS application. I am curious how the author will be able to build from this to describe map densities in the next chapter without reverberating the same information.

Chapter 4

This chapter describes the importance of density maps and explains how to create the two distinct types: (1) by defined area and (2) by density surface. First, as the previous chapters, he reverberates some of the primary information for why you should have an objective in mind when creating maps of any kinds. However, he describes that for density maps, they are “useful when mapping areas…which vary greatly in size.” Then, the author describes in greater detail the two distinct types of density maps. He says, map density by area when “you have data already summarized by area, or lines or points you can summarize by area.” On the other hand, Mitchell states to create a density surface when “you have individual locations, sample points, or lines.” Then, he goes into broader detail about each type with how each are calculated, displayed, and finally analyzed.

Honestly, I found this section to be a little redundant, but I understand its importance. Without a firm understanding of density maps, there’s a lot of data that cannot be properly analyzed. In addition, this sort of mapping is commonly what I see when I go to various databases. It is fairly easy to interpret, and from the sounds of it, pretty easy to map on your own—if you know some basic math.