The Effect of Land Fragmentation on Internal Urban Circulation in Boca Raton, Florida

THE EFFECT OF LAND FRAGMENTATION ON INTERNAL URBAN CIRCULATION IN BOCA RATON, FLORIDA Robert J. Tata* The homogeneous plain is dead! Location theorists such as Von Thunen, Christaller, and their more modern counterparts used the homogeneous plain assumption, of course, only to focus on what they felt were basic location factors. Yet for more practical research work on circulation systems, deviations from the homogeneous plain may greatly impair the efficiency of transportation patterns. Hence, transportation planners need to know the amount and locations of deviations from a homogeneous circulation plain. This study proposes a measure of urban land fragmentation (one type of deviation from the homogeneous plain) and examines its eifects on student travel patterns to three elementary schools (one type of circulation system) in Boca Raton, Florida. LAND FRAGMENTATION. The map of Transportation Obstacles illustrates what is perhaps an extreme case of urban land fragmentation (see Figure 1). Large land users, water bodies, and railroads were selected as the major travel inhibitors in this city. Drainage canals domi­ nate the western part of the city, while the Intracoastal Waterway and residential canals dominate the eastern part. Two longitudinal railways further compartmentalize the city, thereby making east-west travel difficult. Several large land users also cause transportation detours and at the same time take land away from usual urban commercial and service functions. Even though bridges, rail crossings, and service roads sometimes provide breaches through these obstacles, an assumption was made that all are absolute barriers to transportation. This assumption seems justified because the major focus of the analysis is methodological in nature. Simple adjustments to the procedure could be made to solve a specific practical circulation problem. The question now arises about a suitable measure of land fragmentation to determine its relationship to intraurban circulation patterns. A simple azimuthal and linear measurement device was constructed to examine the possibilities for travel within the city. School district boundaries form the regions within which possible circulation was measured, because it is the actual travel pattern of elementary school students which will be compared to the theoretical measure of possible •Dr. Tata is associate professor of geography at Florida Atlantic University. The paper was accepted for publication in June 1972. Vol. XII, No. 2 113 movement. The boundaries of the three school districts used in this study are depicted in Figure 3. A set of evenly spaced control points, shown on the Possible Circulation map (Figure 2) was overlaid on the Trans­ portation Obstacles map (Figure 1). Measurements were made from each control point along the eight, cardinal compass points to the bound­ ary of the region in which the control point is located. The distance to a transportation obstacle was measured and became the numerator; the denominator was the total distance along the same route to the regional 114 So u t h e a st e r n G eo g r a ph er boundary. Measurements for the three northernmost control points in the J. C. Mitchell school district, numbered from 1-3, west to east are shown in Table 1. All measurements were made in tenths of inches on the original work maps. TABLE 1 EXAMPLE OF POSSIBLE CIRCULATION CALCULATIONS, J. C. MITCHELL SCHOOL DISTRICT Points N NE E SE S SW W NW Totals Av. Tran«). InefF. 1 5/5 7/7 9/30 12/50 17/92 4/4 3/3 3/3 60/194 .31 2 4/4 7/7 8/20 10/36 19/92 2/18 1/13 1/8 52/198 .26 3 5/5 6/6 8/10 11/26 17/90 16/33 11/23 7/7 81/200 .41 Source: Calculated by author. Point 1 shows a 5/5 for the North azimuth. This means that it was .5 inches to the boundary along a due North azimuth and no obstacles were encountered. The East azimuth, however, is 9/30 which means that it is 3.0 inches to the boundary, but one can travel .9 inches before an obstacle is encountered. After measurements were made for all azimuths, all numerators and denominators were summed for each control point. The result for point 1 is 60/194 or .31...