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Overall accuracy of benthic habitat classification experimental results using SR, PC SR, deglint and DII images
| ntree | mtry | Impurity | Overall accuracy (%) | |||
|---|---|---|---|---|---|---|
| SR | PC SR | Deglint | DII | |||
| 100 | Square root | Gini | 67.66 | 61.47 | 62.39 | 53.44 |
| Entropy | 66.97 | 60.55 | 63.53 | 54.36 | ||
| Log | Gini | 67.20 | 60.32 | 61.24 | 55.96 | |
| Entropy | 66.51 | 62.16 | 62.16 | 55.96 | ||
| 200 | Square root | Gini | 66.97 | 61.01 | 63.30 | 54.36 |
| Entropy | 66.28 | 62.16 | 62.84 | 55.05 | ||
| Log | Gini | 67.43 | 61.70 | 62.39 | 53.67 | |
| Entropy | 66.97 | 62.39 | 60.78 | 55.05 | ||
| 300 | Square root | Gini | 66.74 | 61.93 | 62.84 | 54.36 |
| Entropy | 67.66 | 61.70 | 61.01 | 55.28 | ||
| Log | Gini | 67.89 | 61.24 | 61.70 | 54.36 | |
| Entropy | 66.97 | 61.01 | 61.70 | 55.50 | ||
| 400 | Square root | Gini | 67.66 | 61.47 | 62.39 | 54.59 |
| Entropy | 67.20 | 61.70 | 61.70 | 54.59 | ||
| Log | Gini | 66.97 | 61.70 | 61.93 | 55.05 | |
| Entropy | 66.74 | 62.61 | 61.47 | 54.82 | ||
AGB growth calculation results for Ea and Th species
| No. | Species | Percent cover (%) | Shoot density (shoot · m−2) | Average growth rate (cm · leaf−1 · 5 days) | DW (gDW · shoot−1 · 5 days) | AGB growth (gDW · m−2 · year)−1 |
|---|---|---|---|---|---|---|
| 1. | Ea | 90.91 | 75 | 6.86 | 0.117 | 641.34 |
| 2. | 54.55 | 52 | 444.66 | |||
| 3. | 52.17 | 73 | 624.24 | |||
| 4. | 76.47 | 84 | 718.30 | |||
| 5. | 36.36 | 43 | 367.70 | |||
| 6. | 45.83 | 105 | 897.88 | |||
| 7. | 66.67 | 55 | 470.32 | |||
| 8. | 20.00 | 34 | 290.74 | |||
| 9. | 30.00 | 79 | 675.55 | |||
| 10. | 37.50 | 75 | 641.34 | |||
| 11. | Th, Cr | 30.43 | 167 | 5.63 | 0.035 | 43.09 |
| 12. | 50.00 | 245 | 63.21 | |||
| 13. | 86.36 | 718 | 185.25 | |||
| 14. | 56.52 | 278 | 71.72 | |||
| 15. | 31.82 | 170 | 43.86 | |||
| 16. | 57.14 | 190 | 49.02 | |||
| 17. | 59.09 | 374 | 96.49 | |||
| 18. | 54.55 | 434 | 111.97 | |||
| 19. | 39.13 | 209 | 53.92 | |||
| 20. | 45.45 | 244 | 62.95 |
The R2 value and resultant regression function from: seagrass at the community level, Ea, and Th-Cr AGCG from AGBG leaf-marking samples_
| Species | R2 | Regression equation |
|---|---|---|
| Community | 0.88 | AGCGc = ((2E–05) × (AGBGc2)) + (0.073 × AGBGc) – 0.3845 |
| Ea | 1 | AGCGEa = ((4E–19) × (AGBGEa2)) + (0.0621 × AGBGEa) + (3E–13) |
| Th-Cr | 1 | AGCGTh-cr = ((–2E–19) × (AGBGTh-Cr2)) + (0.1131 × AGBGTh-Cr) – (1E–13) |
The R2 value and modelling regression equation of seagrass at the community level, Ea and Th-Cr AGB growth_
| Species | R2 | Regression equation |
|---|---|---|
| Community | 0.42 | AGB growth = (–0.0291 × (pCv2)) + (13.793 × PCv) + 57.885 |
| Ea | 0.58 | AGB growthEa = (–0.1449 × (pCv2)) + (19.152 × PCv) + 36.171 |
| Th-Cr | 0.87 | AGB growthTh.Cr = (θ.191 × (pCv2)) + (3.3648 × PCv) + 60.809 |
Error matrix of benthic habitat classification using SR image, ntree 300, mtry log and impurity function Gini index_
| Reference class | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| BSD | CD | MCBS | MCMa | MSBS | C + M | Total | UA (%) | ||
| Classified class | BSD | 149 | 1 | 21 | 0 | 31 | 0 | 202 | 73.8 |
| CD | 2 | 71 | 13 | 5 | 0 | 4 | 95 | 74.7 | |
| MCBS | 17 | 12 | 30 | 0 | 2 | 2 | 63 | 47.6 | |
| MCMa | 0 | 0 | 0 | 0 | 0 | 2 | 2 | 0 | |
| MSBS | 25 | 0 | 1 | 45 | 0 | 71 | 63.4 | ||
| C + M | 0 | 1 | 0 | 1 | 0 | 1 | 3 | 33.39 | |
| Total | 193 | 85 | 65 | 6 | 78 | 9 | 436 | ||
| PA (%) | 77.2 | 83.5 | 46.2 | 0 | 57.7 | 11.1 | OA = 67.9% | ||
Experimental results of RF regression modelling seagrass AGB growth
| Class | Ea | Th-Cr | Ea-Th | BS | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ntree | mtry | Nodesize | RMSE (gDW · m−2 · year−1 | r | R2 | RMSE (gDW · m−2 · year−1 | R | R2 | RMSE (gDW · m−2 · year−1 | r | R2 | RMSE (gDW · m−2 · year−1 | r | R2 |
| 100 | Square root | 2 | 62.58 | 0.93 | 0.86 | 136.84 | 0.76 | 0.58 | 97.41 | 0.76 | 0.58 | 106.80 | 0.82 | 0.67 |
| 3 | 62.16 | 0.93 | 0.86 | 129.22 | 0.80 | 0.64 | 96.54 | 0.80 | 0.64 | 105.40 | 0.82 | 0.67 | ||
| 4 | 62.48 | 0.93 | 0.86 | 130.56 | 0.79 | 0.63 | 104.52 | 0.82 | 0.66 | 100.99 | 0.84 | 0.70 | ||
| 5 | 62.90 | 0.93 | 0.86 | 127.83 | 0.80 | 0.65 | 112.18 | 0.78 | 0.62 | 94.93 | 0.88 | 0.78 | ||
| Log | 2 | 62.48 | 0.93 | 0.87 | 128.91 | 0.80 | 0.64 | 98.82 | 0.77 | 0.59 | 109.29 | 0.81 | 0.65 | |
| 3 | 62.09 | 0.93 | 0.87 | 134.42 | 0.77 | 0.59 | 102.37 | 0.79 | 0.62 | 106.94 | 0.81 | 0.66 | ||
| 4 | 63.02 | 0.93 | 0.86 | 133.72 | 0.77 | 0.60 | 104.97 | 0.82 | 0.67 | 95.03 | 0.87 | 0.76 | ||
| 5 | 63.21 | 0.93 | 0.86 | 125.85 | 0.82 | 0.66 | 95.92 | 0.87 | 0.76 | 99.89 | 0.85 | 0.73 | ||
| 200 | Square root | 2 | 61.04 | 0.93 | 0.87 | 132.94 | 0.78 | 0.60 | 102.63 | 0.74 | 0.55 | 101.43 | 0.84 | 0.71 |
| 3 | 62.11 | 0.93 | 0.86 | 132.32 | 0.78 | 0.61 | 100.14 | 0.78 | 0.61 | 104.07 | 0.83 | 0.68 | ||
| 4 | 61.77 | 0.93 | 0.87 | 128.83 | 0.80 | 0.64 | 94.22 | 0.83 | 0.70 | 97.22 | 0.86 | 0.74 | ||
| 5 | 64.60 | 0.93 | 0.86 | 125.93 | 0.81 | 0.66 | 102.25 | 0.82 | 0.67 | 97.97 | 0.87 | 0.75 | ||
| Log | 2 | 61.34 | 0.93 | 0.87 | 135.83 | 0.76 | 0.58 | 100.43 | 0.76 | 0.58 | 103.97 | 0.83 | 0.69 | |
| 3 | 60.83 | 0.93 | 0.87 | 130.38 | 0.79 | 0.62 | 102.76 | 0.77 | 0.59 | 101.20 | 0.84 | 0.71 | ||
| 4 | 61.93 | 0.93 | 0.87 | 130.45 | 0.79 | 0.62 | 97.18 | 0.87 | 0.76 | 98.90 | 0.85 | 0.73 | ||
| 5 | 63.24 | 0.93 | 0.86 | 125.55 | 0.82 | 0.67 | 98.60 | 0.87 | 0.75 | 97.31 | 0.88 | 0.77 | ||
Rules for developing benthic habitat classification scheme for mapping seagrass AGB growth mapping_
| Category | Rules |
|---|---|
| Dominant | The percent cover of a class is >80% or <80%, while other classes are <20%. |
| Irrelevant | The percent cover of a class is <20% so the class is not included in the classification. |
| Mix | The difference in percent cover between classes is <20%. |
| Sub-class | The difference in percent cover between classes is >20% and the subclass name is added with a ‘+’ sign. |
Classification scheme for seagrass species composition mapping (Wicaksono & Hafizt, 2013)
| Class | Species composition | Explanation |
|---|---|---|
| Ea | Enhalus acoroides | Grows and extends vertically in the water column and sometimes reaches the surface. Other life-forms may exist in this class but are not significant. |
| Th-Cr | Thalassia hemprichii, Cymodocea rotundata, Halodule uninervis, Syringodium isoetifolium, Halophila ovalis | Grows to cover the substrate but does not extend vertically in the water column. Other life-forms may exist in this class but are not significant. |
| Ea-Th | Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, Halodule uninervis, Syringodium isoetifolium, Halophila ovalis | A mix of Ea and Th, Cr species with a significant percent cover ratio. |
Number of training area and accuracy assessment samples for each benthic habitat class_
| Benthic habitat class | Training area | Accuracy assessment samples |
|---|---|---|
| ‘Bare substrate dominated’ | 219 | 194 |
| ‘Coral dominated’ | 109 | 108 |
| ‘Mix of coral and bare substrate’ | 67 | 66 |
| ‘Mix of coral and macroalgae’ | 6 | 6 |
| ‘Mix of seagrass and bare substrate’ | 79 | 78 |
| ‘Coral + macroalgae’ | 10 | 10 |
| Total | 490 | 462 |
The R2 value and resultant regression function from: seagrass at the community level, Ea, and Th-Cr AGCG from photo quadrat samples of AGBG_
| Class | R2 | Regression equation |
|---|---|---|
| Ea | 1 | AGCGEa = ((2E–18) × (AGBGEa2)) + (0.0621 × AGBGEa) + (4E–13) |
| Th-Cr | 1 | AGCGTh-cr = ((–2E–18) × (AGBGTh-cr2)) + (0.1131 × AGBGTh-cr) + (2E–13) |
| Ea-Th | 1 | AGCGEa-Th = ((2E-05) × (AGBGEa-Th2)) + (0.073 × AGBGEa-Th) – 0.3845 |
| BS | 1 | AGCGBS = ((2E–05) × (AGBGBS2)) + (0.073 × AGBGBS) – 0.3845 |