## 2 Materials and Methods
### Geospatial Data Preparation  
To investigate human-caused fires using GIS-based dimensionality reduction techniques in Keelung City, Taiwan, this study organizes geospatial data. Firstly, fire incident data spanning the last decade [16] is collected from the Keelung City Fire Bureau. This dataset comprises eleven varied factors, encompassing fire incident density, population-related, building-related, and economy-related attributes. Table 1 outlines all eleven factors, where Factor 1 denotes fire density per unit area, Factor 2 to Factor 11 represent factors pertinent to fire incidents: Factors 2 to 5 correspond to population-related attributes, Factors 6 to 8 pertain to building-related characteristics, and Factors 9 to 11 relate to economic factors. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Factor Description**} & **Aquired Time** & **Source Data** \\ \hline Factor 1 & Fire density over the past 10 years & 2021 & Keelung City Fire Bureau [16] \\ \hline Factor 2 & Population density & 2021 & Household Registration Division, Department of Civil Affairs, Keelung City Government [43] \\ \hline Factor 3 & Proportion of elderly population & 2021 & Household Registration Division, Department of Civil Affairs, Keelung City Government [43] \\ \hline Factor 4 & Proportion of elderly living alone & 2021 & Department of Social Affairs, Keelung City Government [46] \\ \hline Factor 5 & Proportion of young age population & 2021 & Household Registration Division, Department of Civil Affairs, Keelung City Government [43] \\ \hline Factor 6 & Building density & 2021 & Department of Urban Development, Keelung City Government [47] \\ \hline Factor 7 & Proportion of buildings over 40 years old & 2021 & Department of Urban Development, Keelung City Government [47] \\ \hline Factor 8 & Proportion of non-reinforced concrete (RC) & 2021 & Department of Social Affairs, Keelung City Government [46] \\ \hline Factor 9 & Proportion of first sector of the economy & 2021 & Department of Economic Affairs, Keelung City Government [48] \\ \hline Factor 10 & Proportion of secondary sector of the economy & 2021 & Department of Economic Affairs, Keelung City Government [48] \\ \hline Factor 11 & Proportion of tertiary sector of the economy & 2021 & Department of Economic Affairs, Keelung City Government [48] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Factors from fire datasets in this study. Figure 1: Location of study area and fire incidents over the past decade: (**a**) Location of Keelung City; (**b**) Location of fire incidents over the past decade in Keelung City. The raw data for the eleven factors used in this study are sourced from various departments of the Keelung City Government [16; 46; 47; 48; 43]. This study focuses on inventorying the factors associated with fire disasters and utilizing the GIS as an analytical tool. The various attribute data are digitized and input into GIS software, facilitating the analysis of the data and their spatial applications. To integrate point data for each factor listed in Table 1, which already contains location information, into village units within a GIS framework, we initially import the point data representing specific locations into the GIS software. This dataset may include information on incidents, landmarks, or other relevant point-based data associated with village units. Subsequently, we import village boundary data to delineate the geographic boundaries and extent of each village unit. We subsequently employ spatial analysis tools within the GIS software to perform a spatial join between the point data and the village boundary data, enabling the analysis of the spatial distribution of point data within the village boundaries. This procedure links each point with the respective village unit it pertains to. Upon completion of the spatial join, attributes from the point data can be transferred to the corresponding village units, enabling the aggregation and analysis of point-based information at the village level.