Table 1 Functional parameters and fitting degree of inverse S function.

From: Modeling urban land density with Gaussian and inverse S functions by analyzing urban expansion in Zhengzhou City

Time

Parameters

a

c

d

R²

2000

5.314

0.186

16.621

0.995

2001

5.297

0.187

16.766

0.995

2002

5.268

0.187

17.191

0.996

2003

5.161

0.189

17.576

0.996

2004

5.027

0.193

18.278

0.996

2005

4.903

0.195

19.111

0.996

2006

4.871

0.199

19.959

0.997

2007

4.976

0.205

21.150

0.997

2008

5.002

0.208

21.580

0.997

2009

4.964

0.212

21.904

0.997

2010

4.903

0.219

22.105

0.997

2011

4.885

0.234

22.822

0.996

2012

4.845

0.243

23.291

0.996

2013

4.741

0.261

24.181

0.995

2014

4.766

0.270

24.514

0.995

2015

4.746

0.289

24.835

0.994

2016

4.775

0.303

25.384

0.994

2017

4.897

0.324

25.661

0.995

2018

4.990

0.337

26.071

0.995

2019

4.979

0.342

26.144

0.994

2020

5.006

0.354

26.428

0.994

  1. Parameter a describes the steepness of the curve’s middle section; Parameter c reflects the city’s development intensity; Parameter d describes the horizontal expansion of the main urban area; Parameter R2 indicates the goodness of the curve fit (The Gaussian function model R² is consistent with it).
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