Health outcome maps with fine geographic resolution can be misleading due to random fluctuations in disease rates caused by small numbers. In some cases these maps can also inadvertently disclose confidential data. To overcome these limitations the New York State Department of Health’s Environmental Health Surveillance Section developed the Geographic Aggregation Tool to join neighboring geographic areas together until a user defined population and/or number of cases is reached. This tool can be used to produce maps at the finest geographic resolution practicable.
There are two versions of the tool: an R version and a SAS version. The R version is free and has been tested in R 3.0.2 32 and 64 bit versions, under Windows 7. R programming experience is not needed to run the tool. The SAS version requires proprietary SAS software, and was tested in SAS 9.1 and 9.2.
The program takes a Shapefile as input and outputs a Shapefile and a KML file. The SAS version also output a SAS data and map file, and a *.dbf file.
If the software is used we would appreciate a citation for our work. Suggested citation:
Thomas O. Talbot and Gwen D. LaSelva. Geographic Aggregation Tool, Version 1.31, New York State Health Department, Troy NY, July 2010
The purpose of this tool is to move points randomly within a circular region around each point to preserve privacy in when displaying point maps. It is only available as an R version.
Thomas O. Talbot and Gwen D. LaSelva. Geomasking Tool, Version 1.31, New York State Health Department, Troy NY, July 2010
Extract the downloaded ZIP file to use. See guides for more details.
Extract the downloaded ZIP file to use. See manual for more details.
Aggregation without aggravation: determining spatial contiguity and joining geographic areas using hashing. Babcock, GD. Proceedings of the Northeast SAS Users Group Conference, 2009, and in Proceedings of the SAS Global Forum, 2010.
We are interested in learning about how you are using the Geographic Aggregation and or GeoMasking Tools and if you have any suggestions for improvement. Please send comments to:
Chief, Environmental Health Surveillance Section
Center for Environmental Health
New York State Department of Health