Читать книгу GIS Research Methods - Steven J. Steinberg - Страница 75

The best way to determine the purpose of your research is to think about the central question that you want to have answered. For instance, maybe you are interested in examining whether people who live in a certain section of town (e.g., the poorer section) suffer from respiratory problems. The different parts of the town may be described as being “rich,” “middle class,” or “poor” based on the income levels of residents who live there. The question of health connected to income could be addressed using a GIS. Following the earlier mentioned guidelines for integrating GIS into the study, you would want to determine the study boundaries and relevant geographic features that are going to be part of the study. In this case, you are interested in drawing your study boundaries based on income. In other words, you want to draw a boundary around the low-income section of town, the mid-economic area, and the upscale part of town. Where would you begin? You could begin by looking at US Census data for that town to determine the clusters of different parts of town based on household income. You could then draw your boundaries based on the clustering observed in the US Census data. Step 1 in the process also calls for identifying other geographic features that might be important to your study. In this example, that would include determining the locations of different factories, incinerators, or other production facilities (figures 2.13 and 2.14).

Figure 2.13 Mapped locations of sites listed in the US Environmental Protection (EPA) Agency Toxic Release Inventory (TRI). Sites are displayed here on an interactive map of eastern Massachusetts. These maps help users visually explore data from the EPA’s TRI and Superfund Program. The underlying data are also available for download from the EPA website. Courtesy of the Division of Specialized Information Services of the US National Library of Medicine. Basemap data from Esri, DeLorme, USGS, NOAA, NGA, IFL.

Figure 2.14 Data underlying the map shown in figure 2.13. Data from EPA.

Step 2 in the integration of GIS into your study calls for developing a data dictionary. You as the researcher would determine what level of household income would fit your categories, for example, rich (yearly income over $45,000), middle class (yearly income between $20,000 and $44,999), and poor (yearly income under $19,999). In your GIS, you could also gather information on the level of emissions from these different facilities by looking at the Environmental Protection Agency’s website, where the EPA indicates industrial sites that emit beyond a certain specified level. This would be valuable information regarding air quality that could become a part of your GIS database.

You could interview people who live throughout the town and conduct a survey that inquires about their general health, income, and whether they suffer from any respiratory problems. As long as you know the geographic locations of respondents, you could enter this information, along with the survey answers, into a database. That way, when you conduct your analysis, you will be able to have geographic information for each unit of analysis (e.g., household). If you want to aggregate the data slightly to protect the privacy of the individuals, you could categorize respondents as living in a neighborhood versus at an actual street address. On further investigation, you may want to geographically locate various factories, incinerators, or other production-oriented facilities that could be emitting substances that affect people’s respiratory health.

Another important thing to consider in determining your research purpose is the general theme that is a part of your research question. In the foregoing example, some of the potential themes might be environmental health, social inequality, and/or environmental justice.

After determining the general purpose of your research, you can then ask the question, How would GIS be helpful to the project? In other words, how would using a GIS enhance the study? A GIS is useful because it facilitates a more holistic and contextual view of a research problem or issue. It accomplishes this through bringing together a variety of different data types. Any study that you choose to develop will most likely include a variety of important variables. The trick in using the GIS is to identify which variables will best be studied using a GIS. This topic is discussed in greater detail in the following chapter.