Spatial attenuation characteristics and influencing factors of traffic noise in high-density cities: A case study of Tianjin, China

Open Access

Table A.1.

Urban spatial feature indicator selection.

	Parameter	Definition	Formula	Notes
Building indicators	AHB	The average height of the building within the unit	$AHB = \frac{1}{n} \sum_{i = 1}^{n} H_{i}$ $\mathrm{AHB}=\frac{1}{n}\sum_{i=1}^n {H_{i} }$	n is the number of buildings in the cell, H_i is the height of the building i

		GSI	Ground space index within the unit	$GSI = \frac{\sum_{i} A_{bi}}{A_{cell}}$ $\mathrm{GSI}=\frac{\sum_i {A_{bi} } }{A_{\mathrm{cell}} }$	A _b i is the base area of the building i, A _cell is the cell area

			FSI	Floor space index within the unit	$FSI = \frac{\sum_{i} A_{bi} F_{i}}{A_{cell}}$ $\mathrm{FSI}=\frac{\sum_i {A_{bi} F_{i} } }{A_{\mathrm{cell}} }$	F _i is the number of floors of the building i

				RPBC	The ratio of the total perimeter of the building within the cell to the area of the cell	$RPBC = \frac{\sum_{i} E_{bi}}{A_{cell}}$ $\mathrm{RPBC}=\frac{\sum_i {E_{bi} } }{A_{\mathrm{cell}} }$	E _b i is the length of the boundary of the building i

					LSI.B	Landscape shape index of buildings	$LSI . B = \frac{\sum_{i} E_{bi}}{4 \sqrt{\sum_{i} A_{bi}}}$ $\mathrm{LSI.B}=\frac{\sum_i {E_{bi} } }{4\sqrt {\sum_i {A_{bi} } } }$	–

Traffic indicators	RLI	Road length index within the unit	$RLI = \frac{\sum_{i} R_{i}}{E_{cell}}$ $\mathrm{RLI}=\frac{\sum_i {R_{i} } }{E_{\mathrm{cell}} }$	R _i is the length of the road i, E _cell is the cell boundary length

		RAD	Road area density within the unit	$RAD = \frac{\sum_{i} A_{ri}}{A_{cell}}$ $\displaystyle \mathrm{RAD}=\frac{\sum_i {A_{ri} } }{A_{\mathrm{cell}} }$	A _r i is the area of the road i

			LSI.R	Landscape shape index of roads within the unit	$LSI = \frac{\sum_{i} E_{ri}}{4 \sqrt{\sum_{i} A_{ri}}}$ $\displaystyle \mathrm{LSI}=\frac{\sum_i {E_{ri} } }{4\sqrt {\sum_i {A_{ri} } } }$	E _r i is the length of the boundary of the road i

				LMR	The length of the main road within the unit	$LMR = \frac{\sum_{i} R_{mi}}{E_{cell}}$ $\displaystyle \mathrm{LMR}=\frac{\sum_i {R_{mi} } }{E_{\mathrm{cell}}}$	R _m i is the length of the main road i
Land use indicators				PC	Proportion of commercial land in the unit	$PC = \frac{A_{c}}{A_{cell}}$ $\displaystyle \mathrm{PC}=\frac{A_{c} }{A_{\mathrm{cell}} }$	A _c is the area of commercial land within a cell

					PR	Proportion of residential land in the unit	$PR = \frac{A_{r}}{A_{cell}}$ $\displaystyle \mathrm{PR}=\frac{A_{r} }{A_{\mathrm{cell}} }$	A _r is the area of residential land within a cell

	PT	The proportion of land used for transportation facilities in the unit	$PT = \frac{A_{t}}{A_{cell}}$ $\displaystyle \mathrm{PT}=\frac{A_{t} }{A_{\mathrm{cell}} }$	A _t is the area of traffic land within a cell

		PG	Proportion of green space in the unit	$PG = \frac{A_{g}}{A_{cell}}$ $\displaystyle \mathrm{PG}=\frac{A_{g} }{A_{\mathrm{cell}} }$	A _g is the area of green space within a cell

			DLM	Degree of land mix within the unit	DLM = −∑(L _m i)(lnL _m i)	L _m i is the proportion of land use type i in all land us

				DFM	Degree of functional mixing within the unit	DFM = −∑(F _m i)(lnF _m i)	F _m i is the feature type i in full functionality

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