Personal Summary
Chapter 4:
In chapter four, the topic of mapping density is covered. For context, in GIS, density is equivalent to concentration. By mapping areas of both high and low concentrations, it allows you to recognize patterns. After covering the Why the chapter transitions into the what. It stares that in order to map density, “you can shade defined areas based on a density value or create a density surface. ( This confused me because it didnt explain what each of them were. So I did a little reasearch because I was confused and found that a Density surface is absically a gradient over a wide range while a density value is a bullentin point in a small area that gives specified values). It also talks about using GIS to map both points and lines. ( points make sense to graph but lines not so much, I tried to figure out what it meant but it just confused me more). The last thing mentioned in the topic of “deciding what to map” was the topic of features vs feature values, Which was easy to understand since they gave examples for this one. Mapping features would be like mapping the locations of buisnesses while feature values would be like taking the number of emplyees at each buisness. The chaprer then tells two ways to map density, The first is by mapping a defined area (which is I think using Density value because the images show plots of a small region) in this method you can use a dot map to calculate density for each value. The other method is by density surface (ok I think I was right) which is when each layer gets its own density which makes a gradient type look agross the entire map.
Chapter 5:
The title of this chapter is “finding whats inside” (im gonna take a guess just by the title it might mention how to interpret the density and make sense of it when making a hypothesis) . The chapter starts off by exlpaining the importance of mapping out the inside of an area. It states that “people map what’s inside an area to monitor what’s occuring inside it, or to compare several areas based on whats inside each”. ( I think this is a common thing thats done in most ENVS/BIO type labs at this school. I never realized that GIS was so commonly used and I never knew what it was until this year). An example that the chapter used to express the importance of mapping was by monitoring drug-related arrests within 1,000 feet if a school. In doing so they would give harsher punishments to said dealers. The chapter then goes into “definng your analysis” ( I assumed correctly) . It mentions that you can draw an area boundry on top of the features to help summarize them (this made no sense to me at all, but It could be because I havent done any actual GIS work yet). The chapter also states that in order to analyze your data you have to conside how many and the type of features it contains. (which makes sense because how can you hypothesize something whithout knowing what exactly your looking at). After further reading I think im starting to understand the boundries, I assumed it was no different then any other boundry and it isnt but its there to seperate a specified area from things not considered “in range”.
Chapter 6:
Chapter six is titled “finding whats nearby”, but covers things like defining your analysis, three ways to find whats nearby. (this doesnt really make sense to me considering the last chapter was talking about setting boundries in order to cust things off, but now it wants you to also map whats around)? The chapter starts by explaing the “Why”, turns out its important because lets say your going to like walmart but theres a target close. By having the target pinged on the map it lets you know that theres also a target you could go too. (or at least thats how i interpreted this section of the reading). The chpater also talks about a method used to find whats nearby, the method they mentioned was measuring using straght line distance (is this like literally a straght line from A to B) by doing this they can gain an idea of measuring “nearness”. Another meathod that they said is measuring distance or nearness by travel cost (this was in context to traveling only though). In the chapter it also talks about measuring whats nearby using either distance or cost, it states that you can measure cost in terms of how long it will take to reach points A to B ( I was thinkning like cost as in $, this makes stuff so much more understandable) . The chapter also starts bringing up other topics that I didnt really take into account. For exampke if your measuring travel are you measuring the distance over a flat plane or using the curvature of the earth. ( If im being honest this did not cross my mind but it makes so much more sense to think of this. This makes me wonder if things like google maps uses a flat map or curvature to measure long disances).