Using the Google Earth Engine cloud-computing platform to assess the long-term spatial temporal dynamics of land use and land cover within the Letaba watershed, South Africa

Figures & data

Figure 1. Location of the Letaba watershed, South Africa.

Figure 2. the Schematic flow chart showing steps.

Table 1. Land use and land cover classification description.

Classes	Class no	Description
Bare surfaces (BS)	Class 5	Rocks, bare soil
Built-up (BU)	Class 2	Buildings, roads
Grasslands (GL)	Class 6	Rangelands
Natural Forests (NF)	Class 7	Dense, sparse
Plantations (PT)	Class 3	Tropical, pines, citrus
Water bodies (WB)	Class 4	Dams, rivers, streams
Shrublands (SL)	Class 8	Short trees

Figure 3. Variables of importance percentage derived using the RF variable selection method.

Table 2. Derived LULC error matrix for the year 1990, 2000, 2010 and 2021.

1990	BS	BU	GL	NF	PT	WB	SL	Total	UA	EC
BS	60	0	0	0	0	0	0	60	100.00	0
BU	0	60	0	0	0	0	0	60	100.00	0
GL	1	0	59	0	0	0	0	60	98.33	2
NF	2	0	0	55	1	2	0	60	91.67	8
PT	2	0	1	4	53	0	0	60	88.33	12
WB	2	0	0	1	0	57	0	60	95.00	5
SL	3	0	0	0	1	0	56	60	93.33	7
Total	70	60	60	60	55	59	56	420
PA	85.71	100.00	98.33	91.67	96.36	96.61	100.00
EO	14	0	2	8	2	3	0
		OA	95.24
2000	BS	BU	GL	NF	PT	WB	SL	Total	UA	EC
BS	60	0	0	0	0	0	0	60	100.00	0
BU	1	59	0	0	0	0	0	60	98.33	2
GL	1	1	56	1	0	1	0	60	93.33	7
NF	0	0	0	60	0	0	0	60	100.00	0
PT	2	0	0	3	55	0	0	60	91.67	8
WB	0	0	0	1	0	59	0	60	98.33	2
SL	1	0	0	1	0	0	58	60	96.67	3
Total	65	60	56	66	55	60	58	420
PA	92.31	98.33	100.0	90.91	100.0	98.33	100.00
EO	8	2	0	9	0	2	0
		OA	96.90
2010	BS	BU	GL	NF	PT	WB	SL	Total	UA	EC
BS	59	0	0	0	0	1	0	60	98.33	2
BU	4	56	0	0	0	0	0	60	93.33	7
GL	0	0	56	2	0	2	0	60	93.33	7
NF	0	0	0	57	1	2	0	60	95.00	5
PT	3	0	0	7	50	0	0	60	83.33	17
WB	0	0	0	3	0	57	0	60	95.00	5
SL	0	0	2	0	1	0	57	60	95.00	5
Total	66	56	58	69	52	62	57	420
PA	89.39	100.00	96.55	82.61	96.15	91.94	100
EO	11	0	3	7	4	5	0
		OA	93.33
2021	BS	BU	GL	NF	PT	WB	SL	Total	UA	EC
BS	57	3	0	0	0	0	0	60	95.00	5
BU	0	60	0	0	0	0	0	60	100.00	0
GL	0	0	60	0	0	0	0	60	100.00	0
NF	0	0	0	60	0	0	0	60	100.00	0
PT	0	0	0	0	60	0	0	60	100.00	0
WB	0	0	0	0	0	60	0	60	.00	0
SL	2	0	0	0	0	0	58	60	96.67	3
Total	61	65	60	60	60	60	58	420
PA	96.72	92.31	100.0	100.0	100.00	100.0	100
EO	3	5	0	0	0	0	0
		OA	98.80

Figure 4. Spatiotemporal pattern of LULC at Letaba watershed.

Table 3. Area covered by each class type for four-time period.

	1990		2000		2010		2021
Classes	Area (ha)	Area (%)	Area (ha)	Area (%)	Area (ha)	Area (%)	Area (ha)	Area (%)
Bare Surfaces	645894	44	581998	40	560638	39	418694	29
Built Up	22068	2	47395	3	140123	10	238994	16
Grasslands	335100	23	193814	13	194121	13	134894	9
Water bodies	184736	13	99332	7	106812	7	15595	1
Natural Forests	184049	13	170381	12	142161	10	84325	6
Plantations	57514	4	277227	19	216961	15	343700	24
Shrublands	22503	2	81717	6	91048	6	215662	15
Total	1451864	100	1451864	100	1451864	100	1451864	100

Figure 5. Representation of total area LULC change (gains and loss) on Letaba watershed for the time period 1990, 2000, 2010 and 2021.

Table 4. the rate of change in LULC classes from the year 1990 to 2021.

Class	1990 Area %	2021 Area %	1990–2021 rate of change %
Bare surfaces	44	29	−2
Built-up	2	16	47
Grasslands	23	9	−3
Water bodies	13	1	−4
Natural forests	13	6	−3
Plantations	4	24	24
Shrublands	2	15	41