Identification of Abandoned Tea Lands in Kandy District, Sri Lanka Using Trajectory Analysis and Satellite Remote Sensing
Abstract
1. Introduction
2. Materials and Methods
2.1. Study Area
2.2. Data Collection
2.3. Methods
2.3.1. Define the Land Use/Cover (LULC) Classes
2.3.2. Image Classification Using the Random Forest Classifier
2.3.3. Identification Process of Abandoned Tea Lands
2.3.4. Land Use/Cover (LULC) Trajectory Analysis
- (a)
- Compute trajectories for the five-time period, generating a time series trajectory map.
- (b)
- Evaluate all trajectories and combine necessary trajectories based on the predefined rational rules as shown in Table 4.
Rule # | Trajectory | Trajectory Codes | Description |
---|---|---|---|
Rule 1 | No change | T T T T T, H H H H H, F F F F F, and so forth | A pixel maintains the same LULC class across the five periods, it is considered to be ‘No changes.’ |
Rule 2 | Trajectories for abandoned tea and other LULC classes | T N N N N, T T N N N, and so forth for abandoned tea | Pixels classified into LULC classes other than tea were collectively assigned the code ‘N’ (non tea). |
T N N N T, T N N T T, and so forth for intermediate (2017–2021) abandoned tea | |||
N T N T T, N N N N T, and so forth for tea gain | |||
N T T T N, N T T N N, and so forth for intermediate tea gain | |||
Rule 3 | Other trajectories | G G H H B, F F G H H, H G G W W, and so forth | Pixels classified into LULC classes other than tea throughout all five-time periods were categorized as ‘Other trajectories.’ |
2.3.5. Validation of the Results
2.3.6. Grid-Based Density Analysis
3. Results and Discussion
3.1. Land Use/Cover (LULC) Changes and Accuracy Assessment
3.2. Land Use/Cover (LULC) Trajectories
3.2.1. Tea Land Trajectories
3.2.2. Spatial Distribution of Abandoned Tea Lands
4. Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Sensor | Scene ID | Acquisition Data |
---|---|---|
Landsat-8 OLI/TIRS (Resolution—30 m) | LC81410552015008LGN01 | 8 January 2015 |
LC81410552017013LGN01 | 13 January 2017 | |
LC81410552019003LGN00 | 3 January 2019 | |
LC81410552021024LGN00 | 24 January 2021 | |
Landsat-9 OLI/TIRS-2 (Resolution—30 m) | LC91410552023102LGN00 | 12 April 2023 |
Image 1 | Image 2 | |
---|---|---|
Area of Interest | Deltota, Doluwa, Udapalatha | Ganga Ihala Koralaya, Pasbaga Koralaya |
Sensor | Super Dove | Super Dove |
Instrument | PSB.SD | PSB.SD |
Acquisition Data | 9 April 2023 | 11 April 2023 |
GSD | 3.7 m | 3.9 m |
LULC Class | Code for Trajectory Analysis | Description | Image Reference |
---|---|---|---|
Tea | T | Tea land | a |
Forest | F | Dense vegetation, forest plantation, and scrubland | b |
Built-up Area | B | Urban residential, commercial, industrial, and transportation areas | c |
Home Garden and Other Crops | H | Residence with some form of cultivation, paddy, and other crops | d, e, f |
Grass and Bare Land | G | Grasslands, barren lands, and open spaces | i, j |
Water Body | W | Natural and artificial water areas | k |
LULC Class | 2015 | 2017 | 2019 | 2021 | 2023 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Area (ha) | % | Area (ha) | % | Area (ha) | % | Area (ha) | % | Area (ha) | % | |
Tea | 9818.0 | 21.6 | 7605.1 | 16.7 | 7756.5 | 17.1 | 8458.4 | 18.6 | 8446.4 | 18.6 |
Home Garden and Other Crop | 20,986.2 | 46.2 | 23,970.2 | 52.7 | 21,676.8 | 47.7 | 23,412.0 | 51.5 | 22,156.1 | 48.7 |
Forest | 7361.0 | 16.2 | 6789.8 | 14.9 | 6916.5 | 15.2 | 7132.7 | 15.7 | 7185.1 | 15.8 |
Grass and Bare Land | 6805.5 | 15.0 | 6416.7 | 14.1 | 8425.0 | 18.5 | 5649.6 | 12.4 | 6834.4 | 15.0 |
Build-up Area | 353.6 | 0.8 | 549.2 | 1.2 | 589.8 | 1.3 | 657.5 | 1.4 | 701.7 | 1.5 |
Water Body | 143.2 | 0.3 | 141.0 | 0.3 | 103.0 | 0.2 | 110.5 | 0.2 | 126.0 | 0.3 |
Cloud | 4.0 | 0.0 | 0.0 | 0.0 | 4.3 | 0.0 | 51.4 | 0.1 | 22.6 | 0.0 |
Total | 45,472 | 100 | 45,472 | 100 | 45,472 | 100 | 45,472 | 100 | 45,472 | 100 |
Other LULC | Abandoned Tea | Intermediate Tea Lost or Gain | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Trajectories | Pixel Count | Area (ha) | % | Trajectories | Pixel Count | Area (ha) | % | Trajectories | Pixel Count | Area (ha) | % |
T T T T T | 18,630 | 1676.7 | 3.7 | T T T T N | 7252 | 652.7 | 1.4 | T T T N T | 17,500 | 1575.0 | 3.5 |
H H H H H | 114,595 | 10,313.6 | 22.7 | T T T N N | 3929 | 353.6 | 0.8 | T T N N T | 2799 | 251.9 | 0.6 |
F F F F F | 40,790 | 3671.1 | 8.1 | T T N N N | 5949 | 535.4 | 1.2 | T N N N T | 4194 | 377.5 | 0.8 |
G G G GG | 22,893 | 2060.4 | 4.5 | T N N N N | 21,026 | 1892.3 | 4.2 | T N N T T | 4179 | 376.1 | 0.8 |
B B B B B | 2901 | 261.1 | 0.6 | T N T N N | 5874 | 528.7 | 1.2 | T N T N T | 3254 | 292.9 | 0.6 |
W W W W W | 793 | 71.4 | 0.2 | T N N T N | 6638 | 597.4 | 1.3 | Tea Gain | 43,937 | 3954.3 | 8.7 |
Other LULC Trajectories | 125,524 | 11,297.2 | 24.8 | T T N T N | 5717 | 514.5 | 1.1 | Intermediate Tea Gain | 42,530 | 3827.7 | 8.4 |
T N T T N | 4448 | 400.3 | 0.9 | ||||||||
Total | 326,126 | 29,352 | 65 | Total | 60,833 | 5475 | 12 | Total | 118,393 | 10,655 | 23 |
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Athauda, S.J.K.; Morimoto, T. Identification of Abandoned Tea Lands in Kandy District, Sri Lanka Using Trajectory Analysis and Satellite Remote Sensing. ISPRS Int. J. Geo-Inf. 2025, 14, 312. https://doi.org/10.3390/ijgi14080312
Athauda SJK, Morimoto T. Identification of Abandoned Tea Lands in Kandy District, Sri Lanka Using Trajectory Analysis and Satellite Remote Sensing. ISPRS International Journal of Geo-Information. 2025; 14(8):312. https://doi.org/10.3390/ijgi14080312
Chicago/Turabian StyleAthauda, Sirantha Jagath Kumara, and Takehiro Morimoto. 2025. "Identification of Abandoned Tea Lands in Kandy District, Sri Lanka Using Trajectory Analysis and Satellite Remote Sensing" ISPRS International Journal of Geo-Information 14, no. 8: 312. https://doi.org/10.3390/ijgi14080312
APA StyleAthauda, S. J. K., & Morimoto, T. (2025). Identification of Abandoned Tea Lands in Kandy District, Sri Lanka Using Trajectory Analysis and Satellite Remote Sensing. ISPRS International Journal of Geo-Information, 14(8), 312. https://doi.org/10.3390/ijgi14080312