Table 1.
Data sources used for comparison of forest cover estimates in the Republic of Ireland, outlining the potential advantages and disadvantages of each method.
Fig 1.
Location of counties Longford and Sligo in the Republic of Ireland (shaded green).
Table 2.
PALSAR Data Characteristics.
Fig 2.
PALSAR false colour composites (HH backscatter (red)–HV backscatter (green)–HH/HV backscatter ratio (blue)) for Sligo (a), and Longford (b).
(Source: European Space Agency)
Fig 3.
Box plots of median L-band HH and HV backscatter (γ°) for forest and non-forest training samples for Longford and Sligo.
Table 3.
Radar classification results (RF = Random Forests, ERT = Extremely Randomised Trees, PA = Producer`s Accuracy, UA = User`s Accuracy).
Table 4.
Extremely Randomised Tress (ERT) and Random Forests (RF) forest area (ha) estimates, mean forest size (ha) and overall accuracy (based on independent accuracy assessment dataset) for each of the different post-classification levels for Longford and Sligo.
Corresponding metrics are presented for the Prime2 populated datasets.
Fig 4.
Variable importance scores of the radar backscatter intensities and ancillary data for Longford (top) and Sligo (bottom).
Table 5.
Comparison of classification accuracies with and without the ancillary data.
Table 6.
Forest area (ha), mean forest size (ha), and accuracy (based on independent accuracy assessment dataset) for forest cover estimation in both non-Prime2 populated and Prime2 populated maps, in Longford and Sligo.
Fig 5.
Extent of forest cover in Longford based on (a) SAR RF-5, (b) SAR ERT-5, (c) Forestry2010, (d) Prime2, (e) JRC Forest Map 2006, and (f) Global Forest Change map.
The boxed area indicates the zoom-in area shown in Fig 6.
Fig 6.
Zoomed-in (1: 60,000) extent of forest cover in Longford based on (a) SAR RF-5, (b) SAR ERT-5, (c) Forestry2010, (d) Prime2, (e) JRC Forest Map 2006, and (f) Global Forest Change map.
Fig 7.
Extent of forest cover in Sligo based on (a) SAR RF-5, (b) SAR ERT-5, (c) Forestry2010, (d) Prime2, (e) JRC Forest Map 2006, and (f) Global Forest Change map.
The boxed area indicates the zoom-in area shown in Fig 8.
Fig 8.
Zoomed-in (1: 60,000) extent of forest cover in Sligo based on (a) SAR RF-5, (b) SAR ERT-5, (c) Forestry2010, (d) Prime2, (e) JRC Forest Map 2006, and (f) Global Forest Change map.
Fig 9.
Comparison of HH and HV γ° backscatter for Forest training samples at Longford and Sligo.
Table 7.
Longford and Sligo classification results for multiple classes (RF = Random Forests, ERT = Extremely Randomised Trees, SVM = Support Vector Machines, ML = Maximum Likelihood, PA = Producer’s Accuracy, UA = User’s Accuracy).