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GIS 301 - Skyline College - Forsberg

Assignment 3:
Using Census Data in Assessing children's risk of exposure to lead.

(Part 1 - do in lab, Part 2)

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.

In this assignment you will use GIS methods to collect and analyze maps of census data. Think about what combination of factors in an area would make it a likely candidate for further investigation. That is, where is it most likely that children are being poisoned by lead?


Part 1 - Choose a site and gather maps of data

Data for this project may be acquired online using primarily the U.S. Census Bureau's 1990 data
1990 Census Lookup - by zip
Statistical Resources on the Web Demographics and Housing - census data
U.S. Census Bureau's TIGER Mapping Service "Coast to Coast" Digital Map Database - TMS Version 2.5
Additional detailed base maps with street names can be accessed using Yahoo.com - maps

Choosing zip code(s) for analysis:

Choose a specific place or community in the United States that you would like to research (an urban zip code is often a good unit of analysis). There are three main factors that you should look for.

Leaded paint: using the 1990 Census Lookup - by zip, look up the "year structure built" census data for each zip code and calculate the percentage of housing units built before 1950. Pick one or two adjoining zip codes where at least 27% of the housing was built before 1950. This could be an area of analysis as these structures are more likely to have old lead paint. For more information, read "Lead Inform" On the ground . . .

Leaded gasoline:You may also choose a residential zip code based on its proximity to highways and major arterials (most concentrated near downtowns).

Social statistics: You will want to look for an overlap between those areas with a lot of children and minorities (highest risk groups), with a lot of poor people and renters (more likely to have chipped and peeling paint at home).

Finding data about the area:

Using the TMS Version 2.5, You are to generate and download at least five maps (and their legends) of different themes related to the assigned research theme and place. Remember, all five maps must be of the exact same place and scale so they will line-up when overlaid.

Open the TMS Version 2.5 and scroll to the bottom to where -You can search for a zip code- to find your chosen zip code(s). Zoom in so that your chosen area of analysis is centered and takes up most of the map. Once you are happy with the map, bookmark (favorites) the map so you can bring up the exact same map extent and zoom again later (in case the computer crashes or you are interrupted).

Use the buttons, check boxes, and pop-up menus to select features and data to display. Remember to be very selective so as to not clutter the map and make it unreadable. Note that some features and data are only appropriate or only available at certain scales.

For this assignment, use the menus under "Map Census Statistics." Set the "level" menu to either block group or census tract. Then select the type of data you want to display under the "theme" menu.

Recommended data themes related to children's lead exposure:

You will need to try different options and settings for maps to come out. It involves considerable trial and error.

Saving Data Maps:

Maps and images will be saved into one folder - named after you, and will be used to illustrate a report (remember to always save everything into the same folder). Each map has a legend which is a different image - so save them both and give the names listed below.

To save maps and images, Ctrl-Right Click *on* the image and you will get a menu with an option to "Save Image As...", or "Save Picture As...". Then you can just give it mapname.gif
Be sure to save them all to the same folder.

Filenaming conventions:

for the maps:
chil04.gif - % of population aged 0-4
chil59.gif - % of population aged 5-9
renter.gif - % renter occupied housing
faminc.gif - family income
race.gif - race/ethnicity
for the legends:
give it the same name as the map, but add the letters "leg" at the end. (e.g. renter.gif and renterleg.gif).
proximity to highways and major arterials (major roads should appear in most maps)


Part 2 - Analysis of Maps and Final Essay

The two main sources of lead in the urban environment are lead in gasoline which contaminated soils near roads and highways, and lead in paint which is common in older housing.

Data related to children's lead exposure:

In this assignment you will use GIS methods of buffering and overlay to analyze maps of census data. Think about what combination of factors in an area would make it a likely candidate for further investigation. That is, where is it most likely that children are being poisoned by lead? You will want to look for an overlap between those areas with a lot of children and minorities, with a lot of poor people and renters, and with a lot of older housing located near highways.


Getting more data:

Data for this project was acquired online using primarily the U.S. Census Bureau's 1990 data
1990 Census Lookup - by zip
Statistical Resources on the Web Demographics and Housing - census data
U.S. Census Bureau's TIGER Mapping Service "Coast to Coast" Digital Map Database - TMS Version 2.5
Additional detailed base maps with street names can be accessed using Yahoo.com - maps

Mapping leaded gasoline contamination
Find the major highways and arterials more than ten years old and draw a buffer of one quarter mile on either side of the road. This indicates the areas most likely to have been contaminated by leaded gasoline exhaust coming from traffic.

Finding older housing with leaded paint
Choose a specific place or community in the United States that you would like to research. Look up a map of the zip codes for the area in the yellow pages. Using the 1990 Census Lookup - by zip Look up the "year structure built" census data for each zip code and calculate the percentage of housing units built before 1950. Pick one or two adjoining zip codes where at least 27% of the housing was built before 1950. This will be the area of analysis. For more information, read "Lead Inform" On the ground . . . You may also choose a zip code based on its proximity to highways and major arterials.



Presentation of findings:

You will present your research results pinpointing the most likely places to begin field research of children's risk of exposure to lead in your research area. Your presentation could 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.


Extra Credit: find data for the same area from the 2000 census to compare how the area has changed.


Related links:

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
 The Frequently Asked Questions about the TMS Version 2.5 are very helpful . . .

such as:

Q: Sometime forcing on features doesn't work. What is the deal?
A: There are hardcoded thresholds for feature layers. Most of the features wont
display until you get to a map scale around 1:1500000. This threshold was put in
place to keep users from swamping the CPU with unreasonable requests. (eg. draw all
streets at the US Level).
 
Q: Is there any legal/copyright issues using these map?
A: No. The maps are public domain. You may use them how you wish.
 
Q: How can I download the images I create?
A: That depends on your browser... With Netscape and Microsoft Internet Explorer
you can Ctrl-Right Click *on* the image and you will get a menu with an option to
"Save Image As...", or "Save Picture As...". Then you can just give it mapname.gif.