2.2 SPATIAL ANALYSIS AND PUBLIC HEALTH The conception that we have of GIS nowadays began to emerge in the 1960s, with the development of computerized map systems and the launch of remote sensing satellites of the Earth's surface. According to Smith et al. (2021, ¶ 2), The term ‘GIS’ is widely attributed to Roger Tomlinson and colleagues, who used it in 1963 to describe their activities in building a digital natural resource inventory system for Canada (Tomlinson 1967, 1970). The history of the field has been charted in an edited volume by Foresman (1998) containing contributions by many of its early protagonists. A timeline of many of the formative influences upon the field is provided in Longley et al. (2015, p. 20). The research makes the unassailable point that the success of GIS as an area of activity has been driven by the success of its applications in solving real world problems.
Previous to the conception of GIS, but nonetheless part of its nature is spatial analysis, which can answer several questions related to data that have a geographical component. The table below (Figure 3) provides some examples of the types of questions that may appear in spatial analysis.
Analysis
General Question
Example
Condition
What is...?
What is the population of this city?
Localization
Where is...?
What are the areas with a slope above 20%?
Trend Routing
What has changed...? Where to go...?
Was this land productive five years ago? What is the best way to the subway?
Pattern
What is the pattern...?
What is the distribution of dengue (disease) in Fortaleza?
What is the impact on the climate if we deforest the Amazon? Figure 3. Spatial Analysis. Adapted from INPE, 2006. Model
What happens if...?
In the health care field, these questions can also be asked to answer, for example, who fell ill, and where or when the disease occurred (Hino et al., 2006).
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