Author: ammoore

Chapter 4: 

       Chapter 4 focuses on mapping density through various methods, including defining why you should map density, deciding what kind of density to map, and how to actually map density. In terms of GIS mapping, density refers to the concentration of features or values within a given unit of area/distance. A density map lets you measure designated features by concentration using a uniform aerial unit like hectares or square miles, so the concentration distribution can clearly be observed. A hectare is a metric unit of area equal to 10,000 square meters.

        When discussing why it’s important to map density, Michell gives a multitude of reasons. One being that density maps can help show you where the highest concentration of features/data is located. This makes density maps useful for observing patterns as opposed to observing individual features/locations. These maps are also useful for mapping areas that have a wide variety of sizes. For example, when mapping the number of trees within separate forests, the larger forests may appear to have more trees due to the larger area they take up. However, when mapping for the density of the trees within the forests, you may see more concentrated areas of trees within the smaller forests that are represented through density mapping. 

    As stated in previous chapters, it’s important to consider what information you want to get from the map before creating it. This will help you decide what methodology to use when creating the map. When mapping density, consider whether you want to map direct features or feature values, as the resulting maps can look very different from each other. There are two ways you can map density: mapping the density by area, or creating a density surface. You should map by defined area if you already have data that is summarized by area, or for comparing certain areas with defined borders. On the contrary, you should create a density surface if you want to see the specific analytical concentration of point/line features. Question: What do you do when a data point falls exactly on an existing defined boundary line?

Chapter 5:

         Chapter 5 discusses map/data analysis through the lens of mapping what’s inside. But what does the book mean when it says “finding what’s inside”? It is trying to say that we can identify which geographic features fall within the boundaries of other features using spatial relationships for the purpose of analysis. When in practice using real-life data, this means determining whether points, lines, and polygons are contained within a specific area. This map analysis involves monitoring what’s occurring inside a designated area, or even comparing different areas based on what they contain. In simple words, we are summarizing what’s inside an area using GIS. 

        According to the book, this can be achieved in a multitude of ways. For one, you can draw an area boundary on top of the existing features. Or you can use an existing area boundary to select and analyze the features inside it. You can even combine the area boundary and its features to create a summary of the area. Just like in previous chapters, the method you choose to use for creating your map depends on the data that is available to you and the information you are looking to gain from creating the map. When taking this into account, the type of data you have matters. For example, finding what’s inside a single area vs what’s inside multiple areas can result in different analytical findings, as you can compare multiple areas to each other for deeper data analysis.

         There are three ways of “finding what’s inside” that the book highlights, as I listed previously. In order to draw an area boundary on top of the existing features, all you really need is datasets that show the boundary of the area and the features it contains. To select for and summarize features within an area, you also need datasets that show the boundary and the features it contains, but you will also need the attributes of the features you wish to summarize available. You will need this same set of things in order to perform an overlay of areas and features.  Question: Why does it matter whether you’re working with points, lines, or polygons when figuring out what’s inside an area?

Chapter 6:

      Chapter 6 discusses how GIS mapping can be used as a tool to analyze what is nearby to an existing feature, allowing you to find out what may be occurring within a specific distance from a feature as well as monitor events within that particular feature’s range. This can be useful for various purposes. For example, finding out what’s within the traveling range of a feature can help the observer define the area that can be served by a facility. An ambulance station can do this to find out how far away possible incoming neighborhood calls are to the specific station. Being aware of what is in the traveling range of a feature can also help with designating areas for a specific use relating to the feature being observed. For example, mapping the traveling range around a lake could allow scientists to identify surrounding wetland areas suitable for conducting environmental protection.

     According to the book, you can conduct what was previously described using various methods. One being straight-line distance, in which you specify the feature being analyzed by GIS to measure the direct distance outward from that feature, thus creating an area of surrounding features within that distance. This approach is recommended when you need to create a boundary/select for features around a specific source. To perform this method, you need a layer for the source feature and a separate layer for the surrounding features. Another method you can use is measuring distance/cost over a network. This means to determine the distance or travel cost from a specific source location along a linear feature. This approach is recommended for finding what’s possible within a travel distance/cost of an area located on a fixed network like a road. To perform this method, you need the source feature location, a layer containing surrounding features, and a network layer. Please consider that each part of the network needs an attribute providing its length or cost value. These can either be created manually or chosen from a provided network. Question: Could barriers like rivers or highways affect the analysis of what is nearby to an existing feature?

 

Chapter 1:

 Rather than jumping straight into the intricacies of mapping and data analysis, Chapter 1 stresses the importance of understanding and clearly defining the topic at hand. I believe that this is an effective way to introduce new students to the basics of GIS, as it eases you into it. One major takeaway I noted is that Mitchell highlights how GIS analysis conducted with intent tends to begin with asking the right questions related to the information you need, with more specific questions helping guide your analysis. I had not realized this prior, as I just saw GIS as simply plotting data. I realized we can use GIS to address important problems by asking pressing questions that are specific to the area of interest. It’s also important to note that Mitchell presents GIS systems as accessible, inviting us to ask our own questions and come to our own conclusions and discoveries. This is an exciting revelation for me.

Chapter 1 also introduced me to the basics, like understanding and identifying geographic features as how they are presented within a GIS. My takeaway is that there are many different ways to visualize data as features, depending on what kind of data it is and the purpose of creating a visual for said data. For example, vector vs raster modeling. Vector modeling represents features as points and lines often using coordinate-based data, making it good for plotting things like roads, boundaries, and buildings. Raster modeling represents the features as a grid of cells using continuous data, which is good for plotting things like elevation, temperature, weather patterns, and land types. I found it interesting how these two forms of modeling could technically be used interchangeably for the same purpose, but they are used for whatever they are visually better suited for. 

I feel that explaining how we can all use GIS as an effective tool is the premise and the author’s main goal after reading chapter 1. It introduces GIS analysis as a system that is capable of examining and visualizing geographic data to understand specific spatial patterns, relationships, and trends in a way that I found understandable. It takes this information and directly ties it to visual features within a GIS mapping system. Question: Would reading printed park maps be considered a form of GIS analysis? Where is the line drawn for maps being purely for visualization or analysis?

Chapter 2:

Chapter 2 starts off by building on the foundation that Chapter 1 created by highlighting the importance of visualizing data using mapping. Honestly, I found this redundant. The benefits of mapping data already seemed clear to me. For example, Mitchell discusses how visualising data on maps can help us look for patterns in the distribution of the features, and make decisions based on these patterns. I thought that was obvious, but I appreciate that Mitchell is making things very understandable for new students like myself. Some things that I was unfamiliar with that chapter 2 discusses is deciding what to map, and preparing my data for said map. I learned that when deciding what to map, you need to consider the information you want to analyze and how the map containing this information will be used. This made me realize that it’s important to take into consideration the specific audience the map will be presented to. For example, a highly detailed and overly complicated map is ineffective if it was intended to be made for the purpose of sharing basic information with the general public. As for preparing data, I was highly unfamiliar with the topic. I learned that a crucial first step is to assign geographic coordinates to the feature you wish to plot. Another important thing I learnt is that you need to assign category values to features if there are differing features, or features sorted by type. The category value is a code/tag that identifies the feature type. I often see these categorizations of features when looking at maps, but I’m now realizing that this feature identification can be used for various applications, such as distinguishing areas for city planning. Chapter 2 does a good job at answering basic questions about mapping and how to create a map, as well as explaining how to proficiently analyze these maps.    Question: How can we effectively and critically evaluate data sources to identify biases/untrustworthy information before incorporating it into our GIS analysis?

Chapter 3:

When I first read the title of chapter 3, it being called “Mapping the Most and Least”, I was confused. Unlike the previous titles, what it was trying to convey wasn’t immediately clear to me. However, Mitchell explained it in an understandable fashion. Mapping the most and least means to identify where values relating to your data/criteria are highest or lowest to analyze certain aspects about the data, most often through patterns. If I were to think of an example, I would say that analyzing a low income area for care facilities scarcity is an example of analyzing where values are the least. This is something that I had not previously considered, as I was focused on the idea of mapping where things might be located, not where things might be missing or lacking. It showed me how presenting the quantities of data in different ways is an important thing to consider when deciding what I want the purpose of my map to be. This is just one method of GIS analysis that is presented in chapter 3. Other methods are given.

For example, there are different types of quantities that you can use. According to Mitchell, being aware of the quantity type your mapping can help with deciding how to present your data in the best way. Once the type is determined, a decision must be made about how to represent it on a map. This can be done either through grouping the values into classes or by assigning each value its own individual symbol. I learnt that each choice has its merits, and I now know how to apply them to my own maps. For example, grouping the values into classes is useful for maps with a large range of values to present the data in an easily readable manner. Showing overall patterns is favored over exact data using this type. This would be good for maps about concentration levels of rain or air pollution. On the other hand, assigning each value its own individual symbol is useful for maps where precision matters, and exact values are important due to the specificity of the data. This would be good for maps geared towards recording specific sampling sites, or showing how specific geographic locations may present differently from each other.     Question: What if the data is in a middle ground where it isn’t clear if I should present my data with simplicity or complexity? 

Intro: Hello, my name is Alayna Moore. I’m a Sophomore, and I transferred to OWU at the end of my freshman year.  Delaware Ohio is my hometown, so I always wanted to go to OWU. I plan on double-majoring in Biology (B.A) and Environmental Science (B.A). As for a career, I want to spend time in the field doing surveying. I’m interested in working as an environmental consultant or working for a national park. I also have a deep interest in fungi and have written many amateur scientific papers about them. I’m very new to GIS, but I hope it will help me succeed in these fields of work. In addition to this, I enjoy knitting clothing and doing graphic design when I have the spare time.

Chapter Reflection: After reading the GIS textbook chapter, I learnt a lot of new and interesting information that I was previously confused about. I was largely unfamiliar with the concept of GIS as a whole. I knew it involved mapping and was used in the environmental science field, but that was the extent of my knowledge. Through reading the chapter, I learned that GIS can be applied to various fields and topics. For example, a city planner, a police officer, and a research scientist may all use GIS within their work for different purposes. As a result, GIS can have a massive effect on our societal function from its pervasiveness across multiple important disciplines. I also learned that Spacial analysis is one of the core functions of GIS. Spatial analysis represents more than just geographical data in a visual form, as seen with basic maps. It allows us to gain knowledgeable insights on the data being explored through using a Geographic Information System (GIS) as a tool.  One part of the chapter I found interesting was when early forms of geographic information systems were being discussed, specifically the formation of the Canada Geographical Information System (CGIS). This was one of the earliest operational computer cartography systems as it was created in the 1960’s. I found it interesting because it was created out of a want to gather data on the Canadian forests for the purpose of land management by overlaying the land data with other relevant structures like soil layers and urban areas. This was a wanted concept because this creation would allow for analysis of large amounts of data to determine how one might efficiently manage Canadas forests. As someone who is interested in the surveying and management of land as a potential career path, it was insightful to learn that one of the earliest computer cartography systems was created for that express purpose.

GIS Applications 1:  As previously mentioned, I am deeply interested in fungi and their environments. This led me to discover a scientific report on the topic of mapping soil fungi within a specific region. The researchers decided on mapping the fungi species located in Wielka Żuława island in northern Poland in order to provide a baseline for a new approach towards mapping landscape-scale fungi distribution patterns. The researchers succeeded in their venture of depicting large-scale landscape mapping of the distribution of specific soil fungi within the region, as depicted below.

Source 1:  https://doi.org/10.1038/s41598-023-37538-7

GIS Applications 2: Another topic I am interested in is Invasive species. I find their rippling impacts they have on the environments they are introduced to extremely interesting. Because of this interest, I found a paper published by the U.S. Department of Agriculture relating to the control of a invasive plant species. More specifically, the paper highlights the potential of handled GIS technology in monitoring the control of the species. The paper acknowledges that within Arizona, there are many different invasive species of weed that are impacting the function of Arizonas ecosystems. One solution that is highlighted is implementing the use of handled GIS systems for landowners and managers within Arizona to operate, allowing them to gather and plot data on the invasive weeds. This ability to digitally gather data may allow for more efficient and accurate information on the location and spread of the invasive weed.

Source 2: https://www.fs.usda.gov/rm/pubs/rmrs_p036/rmrs_p036_298_301.pdf