Research Trend Analysis of Geospatial Information in South Korea Using Text-Mining Technology

Table 4

Results of GI-Research Field network analysis (periods 1–4). Italic cells represent the domains in which all network indices are within the top 10 in each period.

Stage	Rank	Frequency		Degree		Closeness centrality		Betweenness centrality
1 (1996~2000)	1	Satellite Image	14	Satellite Image	7	Satellite Image	0.032	Satellite Image	100.68
	2	Natural Disaster	11	Natural Disaster	6	Natural Disaster	0.029	Environmental Impact Assessment Map	72.92
	3	Climate	10	Water Resource	6	Water Resource	0.029	Natural Disaster	51.9
	4	Urban	10	Environmental Impact Assessment Map	6	Environmental Impact Assessment Map	0.029	Climate	48.29
	5	Water Resource	9	Climate	5	Climate	0.028	Water Resource	45.28
	6	Urban Thematic Map	9	Urban	5	Urban	0.028	Urban	44.4
	7	Natural Disaster Thematic Map	8	General-Purpose Map	4	General-Purpose Map	0.026	Biodiversity	35.63
	8	Environmental Impact Assessment Map	6	Natural Disaster Thematic Map	4	Natural Disaster Thematic Map	0.024	General-Purpose Map	23.85
	9	General-Purpose Map	6	Biodiversity	3	Biodiversity	0.023	Natural Disaster Thematic Map	15.24
	10	Forest	5	Air Quality	3	Urban Thematic Map	0.023	Air Quality	12.75
2 (2001~2005)	1	Satellite Image	47	Satellite Image	10	Satellite Image	0.027	Satellite Image	120.77
	2	Climate	42	Climate	10	Climate	0.026	Climate	105.91
	3	Water Resource	27	General-Purpose Map	8	General-Purpose Map	0.023	Atmosphere Thematic Map	69.36
	4	Urban	26	Soil	8	Soil	0.022	Soil	65.66
	5	Natural Disaster Thematic Map	23	Natural Disaster	7	Natural Disaster	0.022	General-Purpose Map	50.74
	6	Natural Disaster	22	Urban	7	Natural Disaster Thematic Map	0.022	Agriculture	50.23
	7	Soil	21	Natural Disaster Thematic Map	6	Atmosphere Thematic Map	0.021	Natural Disaster	45.67
	8	Water Resource Thematic Map	20	Atmosphere Thematic Map	6	Urban	0.021	Natural Disaster Thematic Map	35.93
	9	General-Purpose Map	19	Water Resource	5	Agriculture	0.020	Urban	33.84
	10	Environmental Impact Assessment Map	18	Forest	5	Water Resource	0.020	Ocean	17
3 (2006~2010)	1	Climate	93.0	Climate	10	Climate	0.025	Urban Thematic Map	109.99
	2	Satellite Image	73.0	Satellite Image	9	Natural Disaster	0.024	General-Purpose Map	63.73
	3	Natural Disaster	52.0	Natural Disaster	9	Water Resource	0.024	Climate	63.19
	4	Water Resource Thematic Map	39.0	Water Resource	9	Satellite Image	0.023	Satellite Image	54.21
	5	Natural Disaster Thematic Map	37.0	General-Purpose Map	9	General-Purpose Map	0.023	Natural Disaster	51.15
	6	Water Resource	36.0	Urban	8	Urban	0.023	Water Resource	47.83
	7	Urban	35.0	Soil	8	Urban Thematic Map	0.021	Ocean	47.38
	8	General-Purpose Map	32.0	Urban Thematic Map	8	Aerial Image	0.021	Urban	46.38
	9	Soil	25.0	Water Resource Thematic Map	7	Soil	0.021	Aerial Image	30.87
	10	Atmosphere Thematic Map	25.0	Natural Disaster Thematic Map	7	Water Resource Thematic Map	0.020	Water Resource Thematic Map	26.92
4 (2011~2015)	1	Climate	90	Climate	11	Climate	0.027	Climate	91.07
	2	Natural Disaster	77	Satellite Image	10	Satellite Image	0.027	Satellite Image	64.6
	3	Satellite Image	75	Natural Disaster	8	Natural Disaster Thematic Map	0.024	Forest	59.87
	4	Natural Disaster Thematic Map	50	Natural Disaster Thematic Map	8	Atmosphere Thematic Map	0.024	Agriculture	52.88
	5	General-Purpose Map	45	General-Purpose Map	8	Natural Disaster	0.023	Atmosphere Thematic Map	44.9
	6	Atmosphere Thematic Map	42	Atmosphere Thematic Map	8	General-Purpose Map	0.023	Environmental Impact Assessment Map	38.63
	7	Urban	33	Environmental Impact Assessment Map	8	Environmental Impact Assessment Map	0.023	General-Purpose Map	33.8
	8	Urban Thematic Map	28	Water Resource	8	Water Resource	0.023	Natural Disaster Thematic Map	32.03
	9	Environmental Impact Assessment Map	25	Forest	8	Forest	0.023	Biodiversity	26.95
	10	Biodiversity	25	Biodiversity	7	Biodiversity	0.022	Urban Thematic Map	26.51