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Evaluation of the positional difference between two common geocoding methods.

Publication ,  Journal Article
Duncan, DT; Castro, MC; Blossom, JC; Bennett, GG; Gortmaker, SL
Published in: Geospatial health
May 2011

Geocoding, the process of matching addresses to geographic coordinates, is a necessary first step when using geographical information systems (GIS) technology. However, different geocoding methodologies can result in different geographic coordinates. The objective of this study was to compare the positional (i.e. longitude/latitude) difference between two common geocoding methods, i.e. ArcGIS (Environmental System Research Institute, Redlands, CA, USA) and Batchgeo (freely available online at http://www.batchgeo.com). Address data came from the YMCA-Harvard After School Food and Fitness Project, an obesity prevention intervention involving children aged 5-11 years and their families participating in YMCA-administered, after-school programmes located in four geographically diverse metropolitan areas in the USA. Our analyses include baseline addresses (n = 748) collected from the parents of the children in the after school sites. Addresses were first geocoded to the street level and assigned longitude and latitude coordinates with ArcGIS, version 9.3, then the same addresses were geocoded with Batchgeo. For this analysis, the ArcGIS minimum match score was 80. The resulting geocodes were projected into state plane coordinates, and the difference in longitude and latitude coordinates were calculated in meters between the two methods for all data points in each of the four metropolitan areas. We also quantified the descriptions of the geocoding accuracy provided by Batchgeo with the match scores from ArcGIS. We found a 94% match rate (n = 705), 2% (n = 18) were tied and 3% (n = 25) were unmatched using ArcGIS. Forty-eight addresses (6.4%) were not matched in ArcGIS with a match score ≥80 (therefore only 700 addresses were included in our positional difference analysis). Six hundred thirteen (87.6%) of these addresses had a match score of 100. Batchgeo yielded a 100% match rate for the addresses that ArcGIS geocoded. The median for longitude and latitude coordinates for all the data was just over 25 m. Overall, the range for longitude was 0.04-12,911.8 m, and the range for latitude was 0.02-37,766.6 m. Comparisons show minimal differences in the median and minimum values, while there were slightly larger differences in the maximum values. The majority (>75%) of the geographic differences were within 50 m of each other; mostly <25 m from each other (about 49%). Only about 4% overall were ≥400 m apart. We also found geographic differences in the proportion of addresses that fell within certain meter ranges. The match-score range associated with the Batchgeo accuracy level "approximate" (least accurate) was 84-100 (mean = 92), while the "rooftop" Batchgeo accuracy level (most accurate) delivered a mean of 98.9 but the range was the same. Although future research should compare the positional difference of Batchgeo to criterion measures of longitude/latitude (e.g. with global positioning system measurement), this study suggests that Batchgeo is a good, free-of-charge option to geocode addresses.

Duke Scholars

Published In

Geospatial health

DOI

EISSN

1970-7096

ISSN

1827-1987

Publication Date

May 2011

Volume

5

Issue

2

Start / End Page

265 / 273

Related Subject Headings

  • United States
  • Tropical Medicine
  • Obesity
  • Humans
  • Geographic Information Systems
  • Child, Preschool
  • Child
  • 4202 Epidemiology
  • 4013 Geomatic engineering
  • 1117 Public Health and Health Services
 

Citation

APA
Chicago
ICMJE
MLA
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Duncan, D. T., Castro, M. C., Blossom, J. C., Bennett, G. G., & Gortmaker, S. L. (2011). Evaluation of the positional difference between two common geocoding methods. Geospatial Health, 5(2), 265–273. https://doi.org/10.4081/gh.2011.179
Duncan, Dustin T., Marcia C. Castro, Jeffrey C. Blossom, Gary G. Bennett, and Steven L. Gortmaker. “Evaluation of the positional difference between two common geocoding methods.Geospatial Health 5, no. 2 (May 2011): 265–73. https://doi.org/10.4081/gh.2011.179.
Duncan DT, Castro MC, Blossom JC, Bennett GG, Gortmaker SL. Evaluation of the positional difference between two common geocoding methods. Geospatial health. 2011 May;5(2):265–73.
Duncan, Dustin T., et al. “Evaluation of the positional difference between two common geocoding methods.Geospatial Health, vol. 5, no. 2, May 2011, pp. 265–73. Epmc, doi:10.4081/gh.2011.179.
Duncan DT, Castro MC, Blossom JC, Bennett GG, Gortmaker SL. Evaluation of the positional difference between two common geocoding methods. Geospatial health. 2011 May;5(2):265–273.

Published In

Geospatial health

DOI

EISSN

1970-7096

ISSN

1827-1987

Publication Date

May 2011

Volume

5

Issue

2

Start / End Page

265 / 273

Related Subject Headings

  • United States
  • Tropical Medicine
  • Obesity
  • Humans
  • Geographic Information Systems
  • Child, Preschool
  • Child
  • 4202 Epidemiology
  • 4013 Geomatic engineering
  • 1117 Public Health and Health Services