Project 4: Geocoding Addresses of Customers who Performed Home Radon Tests
GEOG 483
Brian G. Buchanan
Radon is defined as “a cancer-causing natural radioactive gas that you can’t see, smell, or taste” (US Environmental Projection Agency [EPA], 2008). The EPA notes that it is the leading cause of lung cancer among non-smokers (EPA 2008). Radon is formed in nearly all types of soils due to the radioactive decay of uranium. It is dangerous because this radioactive emission enters through the cracks in your foundation and becomes trapped within a home (EPA 2008). Some rock types have a higher radon emanation potential (King and Walrath 2008). These types include shales, glauconite sandstones, phosphorites, uranium-bearing granites, metamorphic rocks, and sheared or faulted rocks (King and Walrath 2008). Because of the dangers associated with radon, the EPA is concerned with identifying geographic areas that potentially could contain the highest amounts of radon.
Home Testing, Inc., (HTI) manufactures home testing kits for radon, and then collects the data. The EPA has contracted with HTI in order to map areas with high radon potential in the Reading Prong area. I was subcontracted by the EPA to geocode the addresses of the customers who performed the home radon tests. I started by attaching the roads, soils, and geology layers to an empty template. Then, using an address locator supplied by the EPA, I performed a “batch match” to match all of the addresses supplied by HTI to the roads layer supplied by the EPA. Unfortunately, there were a number of addresses that did not match. In order to fix the errors and match all of the addresses, I performed an interactive rematch. Through this feature in the ArcToolbox, I was able to fix the errors in the data (mostly spelling or wrong street name) and correctly match the remaining four addresses (Figure 1).
Figure 1: Review/Rematch table showing that there are no unmatched addresses of my batch match and an interactive rematch. This figure was created using ArcView 9.2 on February 3, 2008.
The next step was to perform a union between the soils and geology attribute tables based upon their respective radon potentials. This created a new layer called Radonpot (for radon potential). Within the attribute table of Radonpot, I created a new field and added together the radon potential of the soils and the geology attributes in order to create the total radon potential (RP_Total). I then created a thematic map of the RP_Total showing the breakdown in the Reading Prong area based upon its radon potential as low, medium, and high (Figure 2).
Figure 2: Map of the Reading Prong area showing the total radon potential based upon the radon potential of the soils and the geology in the area. This figure was created using ArcView 9.2 on February 3, 2008.
Now that the map was geocoded and there was a thematic representation of the radon potential within the Reading Prong area, the EPA set up a hotline for people to call to find out the radon potential for their address (King and Walrath 2008). When a person calls in to the hotline, the call taker can use the find command within ArcView to locate the caller’s address, and then using data on the age of home, type of construction, and radon potential, can advise the caller of the dangers of radon in their area. An example of this is a caller who lived at 203 Saw Mill Road in the ZIP code 15370. By using the FIND command, typing in the address and ZIP, and then FLASHING the result, the call taker could show where the caller lived and let them know that they lived in area of high radon potential (Figure 3).
Figure 3: Map of the Reading Prong area showing the geocoded addresses of the households that used HTI's home radon test kit. In addition, the 203 Saw Mill Road address is shown in the southwestern corner of the map as a purple triangle after using the FIND command. This figure was created using ArcView 9.2 on February 3, 2008.
After I finished my project, HTI sent me six new additional customers that I needed to add to my database. I transferred the new data to ArcView and then exported it as data file Geocoding_Result2. I merged Geocoding_Result2 with Geocoding_Result to create the layer Merge_Geocode, which contains all 124 addresses of the people that used HTI’s testing kit (Figures 4 and 5.
Figure 4: Attribute table of Merge_Geocode showing that there are a total of 124 addresses now geocoded; the original 118 addresses plus the six additional customers. This figure was created using ArcView 9.2 on February 3, 2008.
Figure 5: Map of the Reading Prong area showing the 124 geocoded addresses of the households that used HTI's radon testing kit. The six additional customers are shown as red triangles on the map. This figure was created using ArcView 9.2 on Febuary 3, 2008.
I decided that it would be interesting to thematically show the radon potential at each address of the people who used the kits. I created a new layer joining the Merge_Geocode with the Radon_Pot layer. I then created a color ramp using the three categories within the Radon_Pot layer to assign low, medium, and high radon potentials within each address (Figure 6).
Figure 6: Map of the Reading Prong area showing the geocoded addresses and the radon potential at each address. This figure was created using ArcView 9.2 on February 4, 2008.
I was able to combine data supplied by HTI with soil and geologic data supplied by the EPA. I used this data to geocode the addresses of the people who performed a home radon test and returned the results to HTI. I then performed a union of the soils and geology data to combine the radon potential of each in the Reading Prong area. Using both the thematic map and the geocoded data, I produced a map that a call taker with the EPA could use to advise callers from the Reading Prong area of the radon risk of their household.
Sources
King, Elizabeth and Walrath, David (1999-2008) Problem-Solving with GIS, Lesson x, Part y, Section z. The Pennsylvania State University World Campus Certificate Program in GIS. Accessed February 3, 2008.
United States Environmental Protection Agency (2008) Radon. http://www.epa.gov/radon/