Chapter 4: This chapter covers the different ways to map density, and how they might apply to certain map displays more than others. The chapter discusses how density maps can be used to find specific patterns within an area. It explains how mapping different features can completely change a map. For example, Mitchell talks about mapping workers rather than businesses and shows an example. I would have thought that the two maps would have been pretty much the same, but the difference in what was mapped completely shifted the map. Mitchell covers the difference between shaded vs dot density. While I can understand the importance of dot density when comparing specific locations, I prefer shaded density. It is a bit less overwhelming and still displays the data. I also think that dot density can be a little misleading because it doesn’t show the exact locations where the density is higher. The dots are just evenly placed within an area, which can make it a little more confusing. Additionally, dot density can be hard to differentiate when displaying lines of different boundaries because the dots can get lost within the lines. Mitchell also talks about the difference between density surfaces and density areas. While I understand what each is used for, I am still a little confused about how they are different from each other. The author goes on to explain how to calculate density. I understand this to an extent, but I think that I’d have to practice it myself before it fully sticks in my brain. Something that I think is super cool with GIS is how it layers data in order to compare it and add it into one larger set of data. There are so many small things that I wouldn’t think about when presenting density on a map. For example, Mitchell explains the importance of cell size, search radius, calculation method, and units. He explains how these small details can influence how fast a map processes, how detailed the data is, and how difficult or easy the map is to read. Something that I am still confused about, however, is the difference between areal and cell units. In the chapter, he shows an example with two maps, but I don’t see much of a difference between the two.
Chapter 5: This chapter covers how to map small, specific areas and find what falls within those areas. To isolate an area, it is easiest to draw an area map on top of the feature that you have already mapped. This can aid in comparing different areas on a map. In this chapter, Mitchell discusses discrete and continuous features. Something that is a little confusing about continuous features is that they change. I’m wondering if you can only include continuous features at a specific time, or if you have to keep updating the map over an extensive amount of time to see the pattern. Something that I thought was interesting was the different ways you can mark a certain area on the map. Mitchell talks about how you can just include the parts of a parcel within the specific area, and that you can highlight the parcel as a whole. Something else that I found interesting was how much of the work GIS can do for you. Throughout the chapter, Mitchell talks about the many calculations that you might need to do when creating overlays for the map, but he also talks about how easy GIS makes it for you by completing a lot of the other calculations. Mitchell also discusses the different ways to layer the map in order to display the result you want. He goes over the differences and benefits of putting a specific area either under or over the set of boundaries on the map. Another thing Mitchell mentions is the use of frequency in data. He provides examples for different ways to display frequency using charts instead of just maps. He also shows how to display the data using both charts and maps together. Something that I found a little bit confusing when reading about how lines are represented in areas is how they are split up when they fall into multiple areas. Mitchell touches on this briefly, but doesn’t go into depth on it. He talks about the GIS creating a new dataset for the line, which doesn’t make sense to me.
Chapter 6: This chapter covers how to map features within a set distance of a point. This chapter discusses how you can map travel and travel costs in a certain area. This concept is something that I understand to an extent; however, it is still a bit confusing to me. The chapter further explains this concept towards the end of the chapter, but it gets very complex. There are so many little components that go into estimating travel costs. For example, Mitchell brings up how the map creator might estimate the time that a turn takes, or a stop sign, or a light. I understand all of the little components, but it seems like entering all of that data would be very tedious and annoying. Mitchell also brings up the use of turntables to display to data, but that is also confusing to me since he doesn’t go much into depth about it. Another thing that this chapter discusses is inclusive rings. Mitchell shows displays of three different maps with inclusive rings of different sizes. Something that I’m curious about with this is if you have to completely remake the map for each ring, or if there is a way to essentially copy and paste the map so that it is more efficient. A tool that I think is super useful is creating a buffer of features within a certain distance. This allows you to highlight features without creating a border around them. Another way Mitchell talks about displaying data is through a spider diagram. I think that this diagram looks super cool, but I think it could only be used on a small scale. When used on a bigger scale, like he does in the chapter, many of the points blend together and make the diagram confusing. Something that I think is super cool and useful is displaying places within a certain travel cost distance of an area. This can be helpful for owners who might establish a business within that area and want to know how long it takes for their customers to travel to them.