# Land Cover Mapping in Southwestern China Using the HC-MMK Approach
## 4 Results
### The CLC-SW2010 Product and Product Accuracy  
Taking the multi-temporal native HJ-CCD images and Landsat TM images as main input data, the 30 m-resolution CLC-SW2010 product (Figure 11) was produced by the proposed HC_MMK approach over the last three years. In the CLC-SW2010 product, the grasslands and woodlands are the predominant land cover classes, accounting for 45.01% and 34.92% of the land area of Southwestern China, respectively. The areas of croplands and bare lands are less than that of grasslands and woodland, accounting for 10.45% and 6.10%, respectively. Artificial surfaces and wetlands are rarely found in Southwestern China, only accounting for 0.55% and 2.97%, respectively. The grasslands (including sparse grasslands) are mainly distributed on the Tibet plateau (81.06%), Western Sichuan plateau (11.21%) and the Karst region (7.73%). The woodlands are mainly found in Hengduan Mountain, Daba Mountain, Southeastern Tibet and Yunnan province. The cropland is mainly located in Sichuan Basin, Anning River valley and the \"bazi\" regions of Yunnan-Guizhou Plateau. A total of 5924 validation points, which have been collected independently by a third-party group, were conducted to assess the accuracy of the CLC-SW2010 product. After independent validation, the accuracy of the primary categories and secondary categories of the CLC-SW2010 product reached 95.09% and 87.14%, respectively, and the kappa coefficients were 0.9345 and 0.8573 respectively. The detailed precision information of the CLC-SW2010 product is shown in Tables 4 and 5. Figure 10: The results of the spatial consistency checking. (**a**) is the Landsat TM images (path/row: 138/39, acquired on 17 October 2009) used for classification of left mapping unit; (**b**) is the Landsat TM images (path/row: 137/39, acquired on 26 October 2009) used for classification of right mapping unit; (**c**) is the pre-checking classification result; (**d**) is the post-checking classification result; (**e**), (**f**), (**g**) and (**h**) are the enlarged images at black box in the (**a**), (**b**), (**c**) and (**d**), respectively. The wetlands and bare lands have a higher accuracy (>98%) than other land cover classes, and the accuracy of the grasslands is in the end in CLC-SW2010 (Table 4). Confusing with croplands and shrubs is the main reason for grassland inaccuracy. Because the grasslands were usually accompanied by shrubs, especially in the Karst mountainous area, it is difficult to accurately distinguish the grasslands and the shrubs [46]. They have a similar spectral signature between the grassland and the returned farmlands with 15-25 degree slopes. Therefore, these returned farmlands were frequently classified as croplands rather than grasslands in the CLC-SW2010 product. The evergreen needleleaf forests, herbaceous wetlands, rivers, lakes, reservoirs, paddy fields, residential lands and permanent snow and ice have a higher user's accuracy and producer's accuracy than other secondary categories (Table 5). The multi-source and multi-temporal satellite images, geo-knowledge, objected-oriented method and hierarchical classification played its roles in the accuracy of the CLC-SW2010 product. For instance, the spectral and shape signatures of the lakes were highly similar to the reservoirs. However, obvious differences existed in the spatial distribution between the lakes and the reservoirs in Southwestern China, the former mainly distributed in the plateau, and the latter mainly located in the agricultural region, which were useful for exactly distinguishing the lakes and the reservoirs.