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Project 2: Mapping the Census

Lexington, Fayette County, Kentucky

Jim Kompanek

Introduction

The following maps are of my present hometown of Lexington, Kentucky, specifically the Ashland Park neighborhood. The Ashland Park neighborhood of Lexington is a Historic District on the National Register of Historic Places located adjacent to the Henry Clay Estate.  The neighborhood was constructed between 1904 and 1930 and was planned by the prominent architectural firm of Olmstead Brothers of Brookline, Massachusetts (most noted for their design of Central Park in New York City) (National Park Service 2006).  This neighborhood was primarily laid out as single family households (National Park Service 2006) but there are numerous small apartment buildings (2-6 units) and houses converted to apartments scattered throughout.

The following maps were generated using the U.S. Census Bureau's American Factfinder (U.S. Bureau of the Census 2006a).  American Factfinder is the "Census Bureau's primary medium for distributing census data to the public" (DiBiase 2006c).

Reference Map of Lexington, Kentucky

Figure 1 was generated using the US Census FactFinder (http://www.factfinder.gov) with source data obtained through TIGER/Line Files.  TIGER is an acronym for "Topologically Integrated Geographic Encoding and Referencing" (DiBiase 2006).  The TIGER database allows the Census Bureau to link "address-referenced attribute data with geographic locations" (DiBiase 2006c).  TIGER/Line Files use the vector approach of representing geographic data.  The vector approach involves mapping a series of points representing geographic features (either linear, as in a road or a perimeter, as in a city limit, lake, etc.), to create a series of polygons which represent their "real-world" equivalent (DiBiase 2006a).

The scale of Figure 1 is approximately 1:11,800, or about 1.1 miles across the width of the map.  This scale was determined with the aid of JRuler (Spadix Software 2006).  According to JRuler, the screen width of Figure 1 was 15 cm.  As a result, 15 cm on the map equaled 1.1 miles.  The total map width of 1.1 miles could also be stated as 177,027.840 cm (Science Made Simple 2006).  If this data was divided by 15 (to determine an appropriate scale), it would equal 1:11,801.856, or approximately 1:11,800.

As can be observed in the Figure 1 legend, the above map displays Census Tract, Block Group, and Block according to the 2000 census in the Ashland Park neighborhood of Lexington.  Major roads and streets (with their appropriate name) can also be observed, and although at this scale they are not visible, waterways can also be displayed with maps generated by FactFinder. The smallest geographic area represented in Figure 1 is a census block.  According to DiBiase (2006b), "by definition, blocks are bounded on all sides by streets, streams, or political boundaries" and there were approximately 8.5 million blocks in the 2000 census.  Above census blocks, block groups contain several census blocks. A census tract is a larger geographic area that contains several block groups.  Most census tracts in the US contain between 2,500 and 8,000 residents (DiBiase 2006b). The hierarchy of geographic data used by the US Census Bureau can be seen in Figure 2.

In the above reference map, my apartment is located in census tract 6, block 2009.

Figure 2. Hierarchy of geographic data available from the U.S. Census Bureau (2006b). Available at http://factfinder.census.gov/jsp/saff/SAFFInfo.jsp?_pageId=gn7_maps.  Accessed 20 February 2006.

Thematic Maps of Fayette County, Kentucky

Figure 4: Choropleth map generated by the US Census FactFinder (http://factfinder.census.gov) of Fayette County, Kentucky, using source data obtained through TIGER/Line Files, indicating "persons per square mile" from the 2000 census with an approximate scale of 1:215,000 (US Bureau of the Census 2006a). 

Fayette County is located in the Inner Bluegrass region of Kentucky.  It was one of the three original counties in the Kentucky Territory of Virginia (University of Kentucky 2006).  Fayette County is home to the University of Kentucky and Transylvania University.  The city of Lexington (the largest city in Fayette County) was founded in 1775 and named to honor the first battle of the American Revolution (Lexington History Museum 2006). Although the county is one of the oldest in Kentucky, the fact that much of city is comprised of modern sprawl is apparent to any visitor  To demonstrate this point, I chose to examine the population density of the county according to the 2000 census.

Both Figures 3 and 4 are choropleth maps of Fayette County, Kentucky, which display "persons per square mile" according to the 2000 census (US Bureau of the Census 2006a). They were generated using the US Census FactFinder (http://factfinder.census.gov) with source data obtained through TIGER/Line Files.  Although each map looks strikingly dissimilar, they both display the same data (DiBiase 2006b). 

Figure 3 displays the "persons per square mile" according to equal interval classification scheme. This classification scheme divides the data set (persons per square mile) into equal intervals of 2958 persons per square mile. An advantage of the equal interval classification is that outliers drastically stick out (DiBiase 2006b), such as the two high density census tracts observed in the center of the county.

Figure 4, like Figure 3, is also a choropleth map which displays "person per square mile," the only difference is the classification scheme.  Figure 3 utilizes the percentile classification scheme. This scheme groups the population density into five data classes, which contain the same number of census tracts.  This classification scheme is useful because it "prevents the clumping of observations into a few categories shown in the equal intervals map" (DiBiase 2006b), as can be observed with the large number of low density census tracts in Figure 3.

The scale of both Figures 3 and 4 is about 1:215,000, or approximately 20 miles across the width of the map.  This scale was determined in the same manner as Figure 1, with the aid of JRuler (Spadix Software 2006).  According to JRuler, the screen width of both figures were 15 cm.  As a result, 15 cm on the map equaled 20 miles.  The total map width of 20 miles could also be stated as 3,218,688.00 cm (Science Made Simple 2006).  If this data was divided by 15 (to determine an appropriate scale), it would equal 1:214,579.20, or approximately 1:215,000.

A very large portion of Fayette County is either made up of modern, low density housing, or farmland. I chose to examine population density to demonstrate this observation.  The oldest sections of Lexington are confined to the central portion of the city (where the main boulevards intersect, well within the confines of New Circle Road).  These neighborhoods were laid out prior to the advent, or at least the mass production, of the automobile and were generally of higher density to allow for shorter walking distances.  Not surprisingly, on Figure 3, the central portion of the city has the highest population density.  On Figure 4, the second wave of development (primarily low density ranch-style houses on relatively large lots) can be observed between the core of Lexington and New Circle Road (a post-WWII beltway).  On both Figures 3 and 4, medium to high population density tracts can be observed on the outskirts of the city--These can be attributed to modern townhouses and apartment buildings.  Both figures indicate very low density tracts on the far outskirts, not surprisingly, these can be attributed to large farms (especially horse farms) outside of the city.  These observations are all grossly simplified views of population trends in Fayette County but these maps provide surprisingly accurate views of development trends within the county.

DiBiase, David (2006b) The Nature of Geographic Data, Lesson 3.  The Pennsylvania State University World Campus Certificate Program in GIS. Accessed 20 February 2006.

DiBiase, David (2006c) The Nature of Geographic Data, Lesson 4.  The Pennsylvania State University World Campus Certificate Program in GIS. Accessed 20 February 2006.

Lexington History Museum (2006) Lexington History Museum Homepage. http://www.lexingtonhistorymuseum.org/ Accessed 20 February 2006.

National Park Service (2006) Ashland Park Historic District. http://www.cr.nps.gov/nr/travel/lexington/aph.htm Accessed 20 February 2006.

Science Made Simple (2006) Online Metric Converter for Unit Measurements. http://www.sciencemadesimple.net/length.php Accessed 20 February 2006.

Spadix Software (2006) JR Screen Ruler (For Windows 95/98/2000/NT/ME/XP). http://www.spadixbd.com/freetools/jruler.htm Accessed 20 February 2006.

University of Kentucky (2006) Kentucky Atlas & Gazeteer. http://www.uky.edu/KentuckyAtlas/21067.html Accessed 21 February 2006.

US Bureau of the Census (2006a) American FactFinder. http://factfinder.census.gov/ Accessed 20 February 2006.

US Bureau of the Census (2006b) American FactFinder http://factfinder.census.gov/jsp/saff/SAFFInfo.jsp?_pageId=gn7_maps Accessed 20 February 2006