## 3 Results  
### Study Area  
The selected study area was located in Indonesia, Southeast Asia. Indonesia is extremely rich in biological species, and the forest coverage rate has reached 67.8% (according to Globeland30 land cover product 2010, www.globeland30.com).  
The collected verification points whose resolution and time met the requirements include reference data of GLC 2000 (GLC2000 ref), reference data of Globover 2005 (Globcover2005 ref), reference data of system for Territorial Ecosystem parameter (STEP), reference data of visible infrared imaging radiometer Suite (VIIRS), GLCNMO 2008 reference data, Tsinghua University Global validation sample set, and Globeland30 verification points provided by NGCC (National Geomatics Center of China). The collected verification points were filtered because of the inconsistency semantics and resolution between the verification points and the pre-classified image. Figure 2a shows the distribution of reserved verification points according to the source of verification points; Figure 2b illustrates the distribution of reserved verification points in the study area according to the land cover class of Globeland30-2015.  
Because of the limitation of the operation speed and data volume of the algorithm, a small block, as shown in the red frame of Figure 2a,b, was selected as the demonstration area based on the richness of land cover type. The demonstration area was located in the IM0104 of the Geo-Eco zone [22]. Only one zone was involved, thus the subsequent processing was carried out uniformly within this zone. Figure 3a presents the land cover classification map of Globeland30-2015, which was used as the pre-classified image in this study. There were five kinds of land cover in this area according to GlobeLand30 classification schema [11]. Globeland30-2015 had a resolution of 30 m and was based on the classification of remote sensing images within year 2015. The demonstration area had more than 70,000 pixels. The number of available verification points was insufficient to meet the requirements of model calculation. Therefore, some sample pixels were interpreted as supplements to form a sample data set as shown in Figure 3b.  
Using the \"create random points\" function in ArcGIS, the random points were generated and uniformly distributed of the density of 1 point per 4000 m\({}^{2}\). If there was no network collected verification point at or near the position of the random point, then visually interpreted on Google Earth high resolution images was needed. A total of 15,826 sample points were divided into two parts. Of these points, 7913 were used for model simulation (about 10% of the pixels in the demonstration area), and the remaining points were utilized for the final accuracy verification.  
Figure 2: Verification points of the study area (**a**) Verification points according to the origin; (**b**) Verification points according to the classification of Globeland 30-2015.  
In addition to the sample point data, Geo-Eco zoning related attribute data should also be collected. For the demonstration area, the final data source was GDEM 30 m resolution digital elevation data, considering the availability of data, the independence of data, resolution, and year close to 2015 (Figure 4).