Cubic spline population density functions and subcentre delimitation. The case of Barcelona
The presence of subcentres cannot be captured by an exponential function. Cubic spline functions seem more appropriate to depict the polycentricity pattern of modern urban systems. Using data from Barcelona Metropolitan Region, two possible population subcentre delimitation procedures are discussed. One, taking an estimated derivative equal to zero, the other, a density gradient equal to zero. It is argued that, in using a cubic spline function, a delimitation strategy based on derivatives is more appropriate than one based on gradients because the estimated density can be negative in sections with very low densities and few observations, leading to sudden changes in estimated gradients. It is also argued that using as a criteria for subcentre delimitation a second derivative with value zero allow us to capture a more restricted subcentre area than using as a criteria a first derivative zero. This methodology can also be used for intermediate ring delimitation.
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- F Goffette-Nagot & B Schmitt, 1999.
"Agglomeration economies and spatial configurations in rural areas,"
Environment and Planning A,
Pion Ltd, London, vol. 31(7), pages 1239-1257, July.
- GOFFETTE-NAGOT, Florence & SCHMITT, Bertrand, 1997. "Agglomération economies and spatial configuration in rural areas," LATEC - Document de travail - Economie (1991-2003) 1997-16, LATEC, Laboratoire d'Analyse et des Techniques EConomiques, CNRS UMR 5118, Université de Bourgogne.
- Anderson, John E., 1982. "Cubic-spline urban-density functions," Journal of Urban Economics, Elsevier, vol. 12(2), pages 155-167, September.
- Steen, Robert C., 1986. "Nonubiquitous transportation and urban population density gradients," Journal of Urban Economics, Elsevier, vol. 20(1), pages 97-106, July.
- Small Kenneth A. & Song Shunfeng, 1994.
"Population and Employment Densities: Structure and Change,"
Journal of Urban Economics,
Elsevier, vol. 36(3), pages 292-313, November.
- Small, Kenneth A. & Song, Shunfeng, 1994. "Population and Employment Densities: Structure and Change," University of California Transportation Center, Working Papers qt6nk5v6b4, University of California Transportation Center.
- Craig, Steven G. & Ng, Pin T., 2001. "Using Quantile Smoothing Splines to Identify Employment Subcenters in a Multicentric Urban Area," Journal of Urban Economics, Elsevier, vol. 49(1), pages 100-120, January.
- McMillen, Daniel P., 2001. "Nonparametric Employment Subcenter Identification," Journal of Urban Economics, Elsevier, vol. 50(3), pages 448-473, November.
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