Cooper Week 3

Chapter 4

Map densities are very useful for finding patterns, which is very relevant in terms of public health and potential outbreaks that need to be tracked and have surveillance on them. I found the section on deciding what to map based on features and information you need to map to be very useful. I also thought that the business and employees per square mile density map examples on page 109 are very interesting and are a good example of being able to use density maps for finding patterns. I found the dot density maps to be very useful and something that I do not think I have really seen before. I liked how it uses the color key and dots to indicate the values of density, which I find to not only be visually appealing but also useful when interpreting the map. It was also interesting to learn about when dot maps are most effective, like when the dots are too small or too far apart to convey a true pattern to the viewer. I had no clue what a density surface was until learning that it is created by raster layers. I was still slightly confused by what that really meant but the section about what GIS actually does was insightful to learn that it “defines a neighborhood around each cell center. It totals the number of features that fall within that neighborhood and divides that number by the area of the neighborhood.” This made even more sense after reading the section about using graduated colors and how you have to assign values to each layer in order for them to build on top of each other. In addition, the contour feature seems like it will be useful to better define these boundaries of densities in some particular maps that have a rate of change or rapid change.

 

Chapter 5

I liked how Mitchell discussed why mapping inside areas is so important because “by monitoring what’s going on in an area, people know whether to take action.” The example of the district attorney and crimes near schools is not an example that immediately came to mind but is an issue that might not be as easily identified without mapping. The differentiation between single areas versus multiple areas was useful because they have distinctly different purposes in terms of monitoring. Again, some knowledge from statistics courses seemed to be useful when talking about discrete versus continuous features because these definitions are very similar to their statistical counterparts. However, it was good to review that discrete features can be listed or counted or can be summarized by a numeric attribute. Continuous features are defined as features that represent seamless geographic phenomena. Continuous feature examples are categories or classes. The section on information needed for analysis was also very useful to know what type of map you could make with the given example features for a flood plain. The section on “Drawing areas and features” gives a good overview of the importance of what you are trying to portray in terms of features and what you need in terms of data sets. The table on page 147 comparing drawing areas and features, selecting the features of the area, and overlaying the areas and features was useful to understand how each type can be used for different features and their pros and cons. The overlapping areas and features help define discrete features inside continuous areas. I really enjoyed the maps under the “Overlaying areas with continuous categories or classes” on page 167, I think that these were both very useful as an example of how useful this feature can be when comparing different data sets.

Chapter 6 

I think that this section was very interesting because it mentioned how GIS can be used to look at what is happening within a traveling range and not just a fixed spot. I found the example of this to be very useful in terms of understanding what the author meant by looking at what is happening within a traveling range. I think that another good example of this would be notifying people within 500 feet of a health hazard, or maybe in extreme cases or a hypothetical situation – there would be an outbreak of measles. Due to the severity and how contagious measles is and also how long it stays on surfaces and in the air of a room, this technique could be useful in an outbreak scenario because then all of the people within a certain traveling distance in the area could be notified and tested to prevent more cases or severe cases. The section on street segments was also something that seemed very familiar and maybe even “simple” but then when I started reading more about it, it started to become more complicated due to their complexity of networks, distances, and especially costs. Learning about the per-unit cost put things into perspective to me in terms of understanding why our infrastructure is not always in good condition because when you think about this cost per unit and how many units there are in so many places, I have started to understand why everything is not kept up with completely, especially in weather climates that roads will experience freezing and thawing to create potholes (thanks, Ohio!). Learning about cost turntables and how important they are in terms of calculating costs. As much as I really hate to think about money sometimes, I feel like this was a good section to have towards the end of the book because it helped me make sense of how important cost is in terms of GIS.