Spatial-Temporal Evolution Characteristics and Countermeasures of Urban Innovation Space Distribution: An Empirical Study Based on Data of Nanjing High-Tech Enterprises

Table 4

Results of standard deviational ellipse.

Variables	2008–2010	2011–2013	2014–2016	2017–2019
Semimajor axis (km)	27.977	29.528	32.294	31.586
Semiminor axis (km)	13.720	13.713	14.349	14.334
Flattening	0.510	0.536	0.556	0.546
Area (km^2)	1205.786	1271.920	1455.560	1422.213
Center coordinates	118.798°N, 32.009°E	118.807°N, 31.998°E	118.809°N, 31.979°E	118.805°N, 31.987°E
Azimuth angle (°)	167.485	166.396	164.033	163.555

Flattening refers to the ratio of the difference value between the semimajor and semiminor axis length to the semimajor axis length of the ellipse, reflecting the flattening degree of the ellipse.