## 5 Results and Discussion
### Classification Accuracy with Regard to Data Sources and Features
[25] applied the DT classifier to Landsat time series in a binary classification approach between sugarcane and other crops, assessing an OA of 94%. Regarding the accuracy per class, Figure 4 shows that tomato and pepper crops were fairly well identified for all datasets. Again, and always using the no GLCM strategy, the best \(F_{\beta}\) values for tomato (87.7%) and pepper (87%) were attained for the Landsat 8 time series dataset (Figure 4a). With the same strategy, the \(F_{\beta}\) measure reached values of 85.1% and 84.5% for tomato and pepper, respectively, when using the Landsat 8 time series plus WV2 dataset. It is important to underline that \(F_{\beta}\) values for tomato and pepper crops were significantly worse for the datasets where only a single image of WV2 (80.3% tomato and 81.5% pepper) or Landsat 8 September (76.2% tomato and 68.8% pepper) were employed. On the other hand, the other two crops presented much poorer classification accuracies. The best \(F_{\beta}\) value for aubergine identification (60.3%) was achieved using the WV2 dataset with no GLCM strategy. Moreover, an accuracy of 63.2% in terms of \(F_{\beta}\) was reached in the case of cucumber for the Landsat 8 time series dataset and, again, through the no GLCM strategy. Working on 13 outdoor crops, [PERSON] _et al_. [24] reported \(F_{\beta}\) values ranging from 94% for rice to 66.7% for rye, achieving an accuracy of 80% in the case of tomato. More detailed information about the accuracy per class is presented in Table 5, showing the corresponding confusion matrix for the Landsat 8 time series dataset and no GLCM strategy. It can be noted that a large number of under-greenhouse aubergine crops are misclassified as tomato. In fact, aubergine and tomato crops have a similar transplant date in Almeria, usually in August (Tables 1 and 2). Both crops are quite heat tolerant, and in the study area, greenhouse coverings only need a slight white paint layer to protect the crops during the transplant stage. The white paint is usually washed in September or October. Regarding cucumber crops, they have very variable transplant dates, ranging from August to October (Table 2). For early transplanted cucumber crops, the white paint is more intense to protect the small plants during their first stage. A very slight white paint is usually applied when the cucumber crops are planted in early to mid-September and even not necessary when the cucumber plants are planted very late. Furthermore, in the study area and regarding cucumber crops, it is common to rely on a double-roof in the greenhouse, which reduces radiation losses. All of these actions cause a highly variable spectral signature on the shape of the time series profile recorded from greenhouse coverings. Finally, pepper crops are mainly planted during July and August. This is a crop that needs a significant quantity of white paint to enhance the growth of the plant, as well as to protect the transplant stage. Without a doubt, this is the most unique characteristic for the autumn pepper crop in the \"Poniente\" region of Almeria. The pepper crops are mainly misclassified as tomato or cucumber (Table 5). **Figure 5.** WV2 MS and multi-temporal Landsat 8 pan-sharpened orthoimages showing the evolution of some reference greenhouses. (**a**) WV2 true color composite (RGB) 30 September; (**b**) Landsat 8 RGB 11 August; (**c**) Landsat 8 RGB 12 September; (**d**) Landsat 8 RGB 15 November; (**e**) WV2 false color composite (NIR R G) 30 September; (**f**) Landsat 8 false color 11 August; (**g**) Landsat 8 false color 12 September; (**h**) Landsat 8 false color 15 November. Reference objects in red, green, purple and yellow represent tomato, pepper, aubergine and cucumber crops, respectively.