Ch 1: After reading chapters 1-3 from Mitchell’s book, I finally understood the concern Schuurman had when it came to interpreting GIS data. These chapters explained how the GIS analyst has creative liberty to choose how to interpret their data. This includes symbols, classification themes, colors, etc. More specifically, the first chapter further acknowledges and supports the idea that anyone can use GIS. This could mean that the same symbols may be interpreted differently by other people. Also, the foundation of GIS study reminded me of the scientific method. It focused on the importance of formulating a question, gaining background knowledge and interpreting data. More specifically, it emphasized the importance of understanding the audience and type of data. Distinguishing between the different types of methods is helpful in order to get accurate results for GIS maps.
One of the useful methods of organizing data is to put them into categories. Which would group similar features and represent them with a number. This type of classification, data setup, and map patterns reminded me of statistics. Particularly because this chapter provided examples on the different types of maps, patterns and interpretation of data. I learned that there are two different types of maps: vector model, and raster model. A Vector model has each feature described by coordinates in space and is represented by a row on a table. A raster model is where features are represented as cells. The book also mentioned other types such as continuous, discrete, phenomena etc.
However, after reading the first chapter I wanted to know if one GIS system can create multiple maps. Or is it different systems that lead to different maps? With the different types of maps , such as continuous, vector or or raster, I got a little confused on how the GIS system works to create a map.
Ch 2: In the second chapter, I was able to understand the details of making a map through GIS as well as the importance of understanding their patterns. The chapter explains how organizing data using categories, types, or subsets may differentiate the map. Additionally it is also interesting to note that the GIS has a ‘good memory.’ In order to create maps, coordinates have to be given to each feature so the GIS can produce the visual. I thought it was interesting how the system may remember the coordinate or feature. I also believe that having a previous understanding of statistics would be beneficial for GIS, especially when it comes to drawing conclusions. I also felt that this chapter emphasizes similar information from chapter one so it felt repetitive.
One of the most interesting details about the chapter was the importance of focusing on the audience. There were various points throughout the chapter that reminded the reader to carefully choose the details of the map for easy interpretation. One of the details to consider was how the features in different categories may affect the patterns on a map. Especially if these changes would lead to different results. Additionally, having a map reference may help the audience understand the importance of the visual data. One of the most popular methods of helping the reader is to use colors to distinguish information. However, as the chapter mentioned, using more than 7 colors may be distracting since only the majority may distinguish them. Nonetheless, as a visual learner, it was interesting to see the examples used to elaborate on the types of maps and data sets used throughout the research. At the end of this chapter I understood how features work, but I was still struggling to understand if the map came from the analyst, GIS or both.
Ch 3: Chapter 3 further explained the importance of taking into account the type of data one wants to convey and their targeted audience. More specifically, it details the different types of quantities or counts, amounts or numerical values used for a feature. This chapter reminded me of the categorical vs quantitative data in statistics. Some of the details and information from this chapter felt, once again, repetitive. This chapter reminded me even more of statistics when it started to mention the standard classification schemes. These included natural break, quantile, standard deviation and equal intervals. A natural break is a large gap between values. This could mean that a data point is an outlier or the data may be skewed left or right. Quantile is an unequal amount of features, and compares similar areas. Standard deviation identifies features below or above the mean. An equal interval is like the range divided by the number of classes.
This chapter also introduced different maps that included, graduated symbols, graduated colors charts etc. Graduated symbols focused on location and graduated colors focused on continuous phenomena. It was interesting to see how key concepts from the previous chapters would come together. Throughout the chapter, I started to understand that the researcher can choose different symbols that could be used to interpret the data, and afterward it would be inputted into the GIS system. Afterward, a map would be created and it would display patterns, colors, schemes etc. However a map may be different depending on the symbols the analyst decided to use in the system. Which could create different maps. I really liked that these chapters worked as a guide on how to create a GIS map. I hope I got the foundation of GIS but I hope the other chapters will help me better understand the system.