Blog week 3
Chapter 4
This chapter of focused primarily on what density mapping is and the several ways to do this kind of mapping. In the beginning, it begins to explain that density mapping is necessary to show and view the highest concentration of a feature. This can include a wide range of data, such as the number of workers in a business district or the number of homes with children within a certain zipcode. After this, the chapter moves on to describe the different types of density mapping, the benefits and downsides of each, and later describes how to use them and which situations they would be more beneficial to use in.
The two described versions of mapping density include defined areas and a density surface. A defined area is typically a dot map or essentially individual locations. Often, these kinds of maps are used when you’re already using data like a census, which makes it a lot easier to put in the information. The other kind of density mapping is a density surface, which is made through a GIS raster layer or a contour map. This version of a density map is much more detailed than a defined area, but it also takes quite a lot more work to build these maps, so they’re a little more time-consuming and confusing than a defined area. Although they’re definitely worth it to use in situations where more visibility of the details in your map is necessary.
Later in the chapter, it then continues to describe how to map density through processes such as the cell size, search radius, and units. As mentioned in the last few chapters as well, it emphasizes the importance of color gradiance and how to situate it. And lastly, it explains how to view these maps and properly evaluate them.
Chapter 5
At the beginning of chapter 5, it begins to describe the importance of mapping what’s inside individual areas. One of the examples given was related to crime and being able to find hot spots. This seems to be derived from the density mapping described in the last chapter, but is more specifically related to individual regions to better/analyse things. I also liked the example that was used to explain the way in which areas are decided as more valuable than others for conservation purposes. They further explained how mapping these individual areas and features allows you to see what types of features are in which areas and create a better analysis.
Then it later continues to talk about the different ways to find what features are within what areas, that being drawing areas and features, selecting inside areas, and overlapping areas. These are all used to find different information about an area or a collection of areas. They also continue to mention that building a map quite frequently, if done well enough, with me, all you need to do is an analysis of certain data and the correlation between features and areas. They also mention how the different ways of showing a defined area are important, depending on the goal in mind. For example, only adding the border of an area emphasizes the border itself, while shading it in or putting a screen over it emphasizes the area as a whole.
Throughout much of the second half of the chapter, it is almost like a summary or repetition of previous chapters and information. For example, to explain again what vectors are and how rasters are used in GIS, along with what they’re needed for.
Chapter 6
For chapter 6, it explains the different ways of finding information in relation to things nearby to what you’re focused on. It begins by explaining the 3 different ways of finding this information. It begins with straight line distance, which is used to define an area of influence by using boundaries; this is used purely to measure distance. Then later explains distance or cost over a network, which measures travel, through cost and distance. Lastly was cost over surface, which is used to calculate areas and travel range. While measuring this through cost. Another thing that was kind of interesting to me was the distinct bands, which, I’m not sure if this was the intention, reminded me of the Chicago school model that explains the sectors of a city. It isn’t the most accurate example of cities, but it’s just what distinct bands remind me of.
Later in the chapter, it continues to explain the details of the parameters and the necessary parts to finding what’s nearby and how to build maps that will support this goal.
Something I thought that was kind of interesting was the spider diagram, it’s used to help show when a feature is within range/distance to two different/several locations, and mapping with GIS helps to draw lines between the feature and multiple locations,s so it is easier to visualize these attributes.
Something else I thought was interesting was when, later on in the chapter, it begins to talk about mapping classes. There’s quite a bit of difference between how features and classes are mapped; the main thing being that it is advised not to map more than 7 features on a map, but if you map more than that, it just advises you to begin using different colors to depict it properly and without confusion.