3.4 Interactive effect between 3D building metrics
Among the building metrics, the
GeoD factor detector demonstrated that three-dimensional fractal was the
most influential factors, followed by building density (q = 0.186) and
building congestion degree (0.176), then building height (0.153) (Table
3). The results were inconsistent with BRT analysis results, which also
suggested occlusion effects in BRT model.
The
GeoD interaction detector indicated that
enhancement effect exist between
building metrics. The interaction effect of building congestion degree
with building density (BCD\(\ \cap\ \)BD) was greater than that from
the two sub-factors individually. Here, ‘\(\cap\)’ represents
interactions. These finding indicated that the occurrence of urban
flooding would be increased when the building congestion degree included
building density. For building coverage ratio and building height, the
interaction effect was double-factor enhancement, which suggested urban
flooding risks would be enhanced when building coverage ratio included
building height. The interaction effect was nonlinear between building
height and three-dimensional fractal. It means that the explanatory
power of the GD model would not increase when adding both into the
model.