## 3 Results  
### Application Outcomes of Spaces for Rooftop Greening and Roadside Tree Planting  
The application of the developed algorithm to identify locations suitable for rooftop greening and roadside tree planting within the study area are shown in Figures 6 and 7. The satellite imageries of the study area were compared with the analysis results, and accuracy of acceptable levels were identified. Excluding buildings that are over 30 years old and that have sloped roofs or have already applied green planting, rooftop greening is possible in 311,793 of 742,770 buildings. This is about 42% of all buildings in the study area, and it means that green roofs can be applied to a considerable number of buildings. Among the 25 districts in Seoul, the administrative district that is most applicable for rooftop greening is district A. This is because compared with other areas, the buildings recently constructed in the area mostly have flat roofs. The total rooftop floor area of Seoul is 67,128,199 m\({}^{2}\), and the rooftop floor area of buildings that can apply rooftop greening is 35,230,926 m\({}^{2}\). Excluding the total area of 1,942,179 m\({}^{2}\) of auxiliary facilities installed on rooftops, the area suitable for rooftop greening is 33,288,745 m\({}^{2}\), which is 50% of the total rooftop area of Seoul. District B was found to have the most rooftop green areas. The results are different from those in areas where many rooftop-green buildings are suitable. That is because buildings in district B tend to be older than those in district A, but the area of an individual building tends to be greater (Figure 6). \begin{table}
\begin{tabular}{c c} \hline \hline
**Categories** & **Input Condition** \\ \hline integration period & 10 June 2015. (24 h) \\ resolution (m) & stud area A and B: 2 m \(\times\) 2 m \(\times\) 3 m \\  & study area C: 5 m \(\times\) 5 m \(\times\) 4 m \\ initial temperature (\({}^{\circ}\)C) & 24.9 \({}^{\circ}\)C \\ wind speed (m/s) & 2.0 \\ wind direction & 215.3 \\ roughness & 0.1 \\ relate humidity in 2 m (\%) & 40 \\ building & albedo of roofs and walls: 0.3 \\ Experiments & soil & asphalt (Albedo: 0.2) \\ green roof (a) & grass (Albedo: 0.26) \\ roadside tree (c) & height: 23 m, width: 30 m, LAI: 3.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Main Configuration File for Envi-met. Figure 6: Analysis results of locations suitable for rooftop greening. Figure 7: Analysis results of locations suitable for roadside tree planting. The results determined that roadside trees could be planted on a sidewalk with an extension length of 872,725 m and an area of 838,864 m\({}^{2}\). A total of 145,366 trees can be planted in the study area if one tree has a diameter of 6 m. This excludes the sidewalk section around the site of the urban development project, which is currently underway, and more roadside planting is expected in the future if the section is included. The areas where the most street trees can be planted is District C. This is because the municipal maintenance project in District C has secured more sidewalk space than other areas (Figure 7). Meanwhile the area and quantity of greening and tree planting in the location of case study 2 are shown in Figure 8 and Table 4. According to the locational criteria of the developed algorithm, study area B is 1.5 times larger than study area A in terms of the area suitable for rooftop greening. Moreover, 107 more roadside trees can be planted in study area A than in study area B. Study area C does not have buildings that are suitable for rooftop greening due to the age of the buildings and because most regions, excluding buildings and roads, are already greened, so only boundary areas are suitable for planting roadside trees. rooftop greening and roadside tree planting. Furthermore, roadside tree planting produced a better temperature reduction effect than rooftop greening. Figure 10: Results of the Envi-met simulation. Figure 9: Scenarios for analysis of temperature reduction effects.