Stroke risk accessed october risk subhomepage
One of the useful capabilities of GIS software is the ability to overlay multiple layers of data so you can observe where characteristics correlate with each other in space.
This assignment will describe how to perform simple geographic correlation analysis with ArcGIS Online, and export data to Google Sheets for visualization. The example will use stroke incidence rates as the dependent variable and a variety of independent variables derived from stroke risk factors.
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morbidity with other health conditions common in contemporary American life.
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Study Area
This research will focus on geographic correlates of stroke in the
United States. While stroke is common throughout the
country, there are especially high rates of stroke incidence in the
"Stroke Belt", an area that encompasses a number of states in
the southeast portion of the country (Wikipedia 2018).
Questions and Hypotheses
Given an association of many stroke risk factors with poverty, our
research question is: Do areas that have lower income also have
higher stroke mortality?
Dependent and Independent Variable Choropleth
When dealing with causation, the presumed causes are
measured with independent variables and the
effects are measured with dependent
variables. Effects are dependent upon the independent
causes. A choropleth is a map in which area are shaded or patterned
based on a variable. They are a common way of visualizing quantitative
geospatial data.
For this tutorial, we use as an example the dependent variable “mortality” from cerebrovascular disease (stroke) per 100,000 population for 2016 from the CDC's Chronic Disease Indicators.
3)Change Style and Choose an attribute to show with the variable for the condition you want to map. Select ‘Stroke Mortality per 100K’ as your attribute to show. The map immediately updates in a choropleth style.
4)Select a drawing style of Counts and Amounts (color) to create adjust your choropleth, and configure the Options.
8)Save the map under a meaningful name. Because ArcGIS Online is a shared resource, map names must be unique in an organization. Using your name in the title will help keep the name unique in your organization so there is no naming conflict.
9)Share the map with Everyone (public) to get a URL link you can share
This means that if the shape of both layers is exactly the same (states), ArcGIS Online will combine the tables.
For this example, we use a layer of median household income from the 2013-2017 American Community Survey five-year estimates.
5)Accept the default setting for ‘Choose Join Operation’…It will join one state record to the corresponding state record in both tables.
6)Give the layer a meaningful name. Add your name or initials to create a unique name within our organization.
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10)Click Run Analysis. This join may take a minute or two, although this tool has a tendency to complete without notifying the user. If you are waiting for more than two minutes, create a new map and find the joined layer. AGOL will continue to complete the task on its own servers, evey if you are not viewing the progress in a map. Simply search again for the layer you just made.
11)Examine the attribute table of the resulting layer to make sure all attributes are there and look like you expect. In this case, you’ll see both income and health related variables together in one table.
To transfer your data to Google Sheets for visualization, you need to export the attributes of your combined layer to a CSV file, and then download that CSV file to your computer.
1)View the item details for your layer containing your dependent and independent variables (the new layer you just created). Click the ‘More Options’ button. Select ‘Show Item Details’. You are brought to the layer’s metadata page.
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Correlation Analysis: X/Y Scatter Chart
Correlation is a relation existing between phenomena or things or between mathematical or statistical variables which tend to vary, be associated, or occur together in a way not expected on the basis of chance alone.
2)Import the CSV you downloaded from ArcGIS Online into your spreadsheet. Click File>>Import and navigate to the location of your CSV file. Accept the default settings in the import file dialog box. Your new data should appear in the cells.
3)Give the spreadsheet a meaningful name. Simply click on the title above your sheet. The name should be like “Stroke vs. Income_your name”.
8)Publish chart to get a Link (if you are sending a link to someone) or Embed an iframe(if you are embedding the chart in a web page)
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b.Share the map with Everyone (public) and copy the URL link to share. Paste this URL underneath your screenshot.
4)A Factors section: a paragraph explaining your independent variable (income) which was measured against your dependent variables (stroke) (1 pt) Why is income an important element to study as a potential factor in stroke rates?
b.Provide a screenshot of the scatterplot for your independent variable tested (income) that shows the R2 value and explain the significance of the R2 values from each. Was this a strong positive or negative correlation?
c.A proper citation for each of your data sources.
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You are able to perform an analysis on stroke mortality rates by measuring a second independent variable – Smoking.
Return to your initial mapping steps above and use a different feature layer to join to your CDC table. Search our organization for ‘behavioral risk’. A new feature layer called ‘Minn 2017 Behavioral Risk Factor Surveillance System States’ will appear. This data source contains the percentage of smokers for each state.
American Stroke Association. 2018c. "Stroke Risk." Accessed 27 October 2018.
Risk_UCM_308539_SubHomePage.jsp.
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