11/29/2010 Why Create/Install New Mapping Data Files?

This weekly blog will deal with things GIS, including Computer Cartography, Thematic Cartography, Census Data, and other areas of interest.

The process for creating new Mapping Data is very time consuming. A valid question is – Why create/install new Mapping Data files?

The primary answer is that there has been changes in Census Tract boundaries, either wholesale (Census 2000, Census 2010), or because specific Census Tracts have been modified (beginning in 2004, the new Broomfield County, CO was required – this new County was created by splitting 14 Census Tracts).

The secondary answer is that there have been changes to the “support” cartography files: new water boundaries have been incorporated into the new data, or, as in the case below, new roads have been constructed. This example shows, in the East Hartford, CT area, the continuation/finalization of Interstate 291. The top map is from old TIGER files (pre-2007), and the bottom map is from the 2009 TIGER files:





It is, of course, a business decision on how often to upgrade your Mapping Data (annually? Every 3-or-4 years?). My experience is that users are very familiar with their own local geographies, and are quick to point out the absence of Major Highway Construction in their Mapping Software. A reliable source of relatively-current Mapping Data is essential to satisfy, and retain, clients.

Dennis C. Dixon
Geo-Information Specialist
Dixon Spatial Consulting
dennis.dixon@dixonspatialconsulting.com

11/22/2010 GeoDemographic Analysis

This weekly blog will deal with things GIS, including Computer Cartography, Thematic Cartography, Census Data, and other areas of interest.

This past week has been busy - after downloading and installing the FFIEC 2010 Census Data Application (http://www.ffiec.gov/cra/censusproducts.htm#censusdata), a Report showing Tract Median Family Income and MSA-level Median Family Income is run for all the Census Tracts, but only one State at a time. The data is saved as a txt file, and opened in MapInfo. A master table is made by appending all the txt files. After appropriate database-field-manipulations, a unique FIPS code is generated for each record, which corresponds to the unique FIPS code in the previously-created Nationwide Census Tracts file. After calculating "Income as a % of MSA Median" for each Census Tract, each Tract is either
Low-Income (0.01% < 50%)
Moderate-Income (50% < 80%)
Middle-Income (80% < 120%)
Upper-Income ( >= 120%)
NA (zero families in a Tract means no Tract Median Family Income)

For my first project, I am interested in where 4 Census Tracts meet, and each of the 4 is in a different Income Level:



This map of Midland, TX shows 4 Tracts intersecting at N Big Spring St and W/E Scharbauer Dr, and each Tract is in a different Income category. A bank that wants to locate a branch in this area would make a big mistake to locate it in Census Tract 0002.00 (the Upper Income Census Tract); they would get "extra credit" in any Examination if they were to locate their branch in a Low Income Census Tract - in this case, Tract 0016.00.

This intersection is one of 42 that I have identified. Please contact me if you would like information about the other 41 locations. I enjoyed this project - it combines the need for sophisticated (and automated) data-processing with the need for just some raw "grunt work"; but the results are worth the effort.

Dennis C. Dixon
Geo-Information Specialist
Dixon Spatial Consulting
dennis.dixon@dixonspatialconsulting.com

11/15/2010 First Thoughts

This weekly blog will deal with things GIS, including Computer Cartography, Thematic Cartography, Census Data, and other areas of interest.

The first issue is to identify your client, and their requirements. A map of Housing Index data means both county-level and MSA-level data; an appropriate visualization would be to extrapolate current counties/MSAs back in time, according to the data. For a bank Compliance Officer, a 2010 map of Census Tracts shaded by "Income as a % of MSA Median", however, would use Census Tracts (boundaries defined by the US Census Bureau), but only those FIPS Codes mandated by the Federal Financial Institutions Examination Council (the FFIEC).

Each year, the FFIEC issues "A Guide To HMDA Reporting: Getting It Right!". Among other changes, the 2010 edition was updated to reflect the US Census Bureau making a couple changes to county codes in Alaska, separating Hoonah-Angoon from Skagway-Hoonah-Angoon (232) and assigning Hoonah-Angoon (105) as a separate small county; and giving a new county code 230 to Skagway.

The FFIEC has chosen to wait until 2010 to apply a County-change in Alaska that the US Census Bureau officially noted was effective June 20, 2007. Additionally, the FFIEC has not yet implemented 2 additional Alaska County-changes, one of which was was officially noted effective 5/19/2008, and the other effective June 1, 2008.
http://www.census.gov/geo/www/ansi/changenotes.html

The point is, for 2010 Census Tract Mapping for Bank Compliance Officers, yes - remove Alaska County 232 and include Alaska Counties 105 and 232, but no - do not change Alaska Counties 130, 201, 280.

Note for HMDA Geocoding users: 904 MAIN ST, SKAGWAY, AK 99840 should geocode to County 230, Census Tract 0001.00 for 2010, but to County 232, Census Tract 0001.00 for prior years.

Dennis C. Dixon
Geo-Information Specialist
Dixon Spatial Consulting
dennis.dixon@dixonspatialconsulting.com