Ch 4: Chapter four was very specific when it came to creating density maps, which are maps that show the level of concentration in different areas. Reading patterns on these maps are easy and useful to understand. Additionally, these maps can map density of features or feature values. Furthermore, these maps can map defined areas but not specific centers of density. One type of this map includes dot density maps where each area is based on how much each dot represents. There are two specific versions of creating this type of map. One way is by representing the data graphically and the other way is when the analyst would individually control the amount of dots represented. The other type of defined area map is a shade density area map, which is similar to mapping ratios, class ranges and colors. These types of map styles were mentioned in chapter one.
In order to map specific places, using a density surface map can identify individual locations. This type of map is good for point or line features that are concentrated. Although, with this type of mapping the GIS would choose a radius to identify the features within the area in order to map the data. Another important aspect of density maps are the density values. One way of creating density values was to use cell size which can determine the clarity of patterns. Typically the smaller the cell the smoother the pattern, and the larger the cell the pattern is more coarse. At the end of the chapter, I realized there is a lot of work when it comes to creating GIS maps. It is also important to remember previous topics. Terms such as equal intervals or quantiles were brought up from chapter three when using graduated colors to map density surfaces. It is important to keep up with the readings and not forget previous subjects.
Ch 5: Chapter five was very specific when it came to choosing the best method of selecting areas within a map. I learned that it is important to map areas to monitor current events within it and it is good for comparing any patterns or important information. In order to compare areas it is important to analyze the type of data used to describe each area. For example, if it was a single area, the researcher would monitor the activity or summarize the information. Contrary, if it is multiple areas, the research would see how much of something is inside each area to compare. Another important aspect of mapping areas is to consider what kind of feature is inside each area. This can help determine which method to use to organize the data. The researcher could use a list feature which is listing all the features inside an area. One could use a count feature which totals the number of features inside an area. Summarizing the number of features within an area is a final method of collecting information.
However, each type of method comes with its own challenges when it comes to including the total amount in an area. For example, using a list feature would require an inclusion of areas partially inside a boundary. Meanwhile, other features may have to be fully included within a boundary. I believe that this is another example of the difficulties of interpreting data that the GIS system has. Furthermore, most of the data comes down to whether it is discrete or continuous. This means that the rest of the analysis is based on the type of data. Despite all the particularities of creating area maps, and interpreting data, it will make conclusions easier in the end. Especially when it comes to creating data tables or charts to represent data statistics.
Ch 6: In chapter six I learned about mapping data information nearby the feature or original data. Gathering this information could help map and discover ongoing events nearby or plan for future projects. One of the methods used to gather nearby data is using distance, where time, money or distance is measured using straight lines within featured areas of influence. This method is efficient to estimate travel range. One way of achieving this is by using buffers which are extended lines to measure area within the features. Although, this data can use time or money to measure the straight line distance as well. Assuming that GIS measures the same distance, I wonder if the results would be the same even if the straight line distance was measured in different units.
Additionally, it is also important to figure out how to interpret the values corresponding to the spatial area. There are some maps that would prefer to model the data on a flat surface while others prefer a round surface. The planar method is when the area is small enough to be represented and shaped as a flat map. Contrary, the geodesic map is when the area is large enough to appear correctly on a curved surface of a globe to present accurate results. Furthermore, the chapter also mentioned the importance of using count summary as previously mentioned in chapter five. This seemed a bit repetitive and redundant, but it may also serve as a reference for the researcher to build on previous skills and enhance what they already know. In this second reading assignment I was able to learn a lot about mapping densities and areas. As well as the importance of paying attention to nearby surroundings. It is also interesting to notice how previous skills and details build onto each other as the book progresses. Sometimes it enhances a previously mentioned topic, but other times it does feel repetitive. Nonetheless, I was intrigued by the amount of GIS knowledge I gathered and can’t wait to try it out!