Scenario: You are conducting a survey in the community to assess the children's risk of exposure to lead. Because of a very limited budget, you are only able to conduct a few dozen home visits. That is why you must look at demographic data to pinpoint the most likely places to begin field research of children's risk of exposure to lead.
Data related to children's lead exposure:
proximity to highways and major arterials (requires buffer analysis)
age of housing or 'year structure built'
% of population aged 0-4
% of population aged 5-9
% renter occupied housing
In this assignment you will use GIS methods to collect and analyze maps of census data to pinpoint where you are most likely to find children most at risk of lead poisoning. You want to use overlay analysis to look for places with a lot of poor minority children who live in older rented housing. Finally, if you are using ArcView, you can combine this query with buffering to determine which of the places selected so far are within a quarter mile of a highway.
Data for this project may be acquired from the computers at school (explained below), or online using ESRI ArcData Online.
Additional detailed base maps with street names can be accessed using Yahoo.com - maps
Choosing an area and collecting data for analysis:
Choose a specific place or community in the United States that you would like to research. Using ArcView, open the datasets on your local hardrive found in the ESRIDATA folder. ESRI-3 has detailed datasets for the Western US listed by state. These datasets are probably to big to take with you, so we'll 'clip out' the part you want.
Open the datasets for zip codes and block groups (for California, open cablkgrp and cazip). Put blockgroups at the top of the legend and turn on both block groups and zip codes. Then, zoom in on the community you will research. Click on blockgroups in the legend to make it active. Using the 'select feature' tool +, hold down the shift key and click on each block group to select all of the ones in the community you wish to research. You can use the zipcode theme as reference (turn block groups off to see the zip code). When you have selected all of the blockgroups, choose "covert to shapefile" from the 'Theme Menu.' Give the new theme a new descriptive name and save all the data to the same project folder. You can use the same technique to 'clip out' portions of other large datasets.
The following population data themes are related to children's lead exposure:
The following "housing characteristics", are related to children's lead exposure:
Another important factor in choosing a neighborhood is its proximity to highways and major arterials.
Analysis of Data and Final Essay
The goal is to pinpoint the most likely places to begin field research of children's risk of exposure to lead. Analysis should be done using either ArcExplorer or ArcView GIS.
Overlay analysis: You will perform an overlay analysis by using the query builder in ArcView.
Start a new project in ArcExplorer or in ArcView and add the dataset(s) you've downloaded. Use the Query Builder to combine queries and search for those census blocks which have the greatest combination of data themes related to children's lead exposure.
For example: I want to see which block groups have more than 15% of children in poverty, and 5% of the children are 0-5 years old, and more than 5% of the children are 5-9 years of age, and where the population is at least 30% Hispanic or 30% Black. In the query builder the equation would look like: ( [P_childpov] > 0.15) and ( [P_age05_09] > 0.05) and ([P_agelt_05] > 0.05) and ([P_hispanic] > 0.3) or ([P_black] > 0.3).
Buffer analysis (optional)
Once you have performed the query and have a selection of places, you can further refine your search to include only those places within a quarter mile of a highway by following the directions outlined in the ArcView handout "Refining a query with the Select by Theme option."
Choose the "Select by Theme" option from the theme menu. In the pop-up menus
select themes "that are within distance of"
the selected features of "the theme with the selections"
selection distance is .25 miles
Click on the button "select from set" in order to eliminate selections further than one quarter mile from a highway.
Finish the Map
Once you have performed the query, expand the view of the map to show all block groups. Under the View Menu, choose layout. Add a title, scalebar, etc. to give the map its final touch.
Export the Map (optional)
Under the file menu, choose "Export" and save the image as a jpeg (choose the jpeg option under the pop-up menu called "List files of type"). You can now open the map in a browser, or insert it into a word document to print out.
Final Map and Essay:
The final product of this assignment should be an brief essay and a map that pinpoints the most likely places to begin field research of children's risk of exposure to lead. Your final essay should include analysis methodology, research questions, critiques of the data categories or levels of resolution, and a summary of what you learned. Please spell out exactly how you arrived at your conclusions.
Hand in the final map and essay along with all of the maps and other data used in your research. If you use other sources of data than those mentioned above, please include full citations and a bibliography to tell me where you got your maps and other information.
Dumbing Down the Children--Part 1, Part 2, Part 3
Lead Inform - On the ground . . .
Statistical Resources on the Web Demographics and Housing - census data