Statistics

Accessible via Processing > Cityseer > Statistics. Computes localised statistics for one or more numerical data columns within distance thresholds along the street network.

Input Parameters

Parameter	Description	Default
Street network line layer	A line layer in a projected metre-based CRS	(required)
Data layer	A point or polygon layer containing numerical data	(required)
Numerical field(s)	One or more numeric columns to compute statistics on; all selected fields are computed in a single network pass	(required)
Distance thresholds	Comma-separated distances in metres	400,800
Max assignment distance	Maximum distance (metres) to snap data points to the nearest street segment	400
Use simplest path (angular)	Use angular (simplest) paths instead of shortest (metric) paths on the internally constructed dual graph	False
Boundary polygon	Optional polygon layer. Nodes inside the boundary are used as sources; nodes outside provide network context only.	(none)
Decay expression	Advanced. Distance-decay weighting for the statistics. Default 1 weights all contributions equally.	1
Time thresholds	Advanced. Comma-separated minutes; overrides distances when set. Converted to metres using the walking speed.	(none)
Walking speed	Advanced. Metres per second, used to convert minutes to distances.	1.33

Only numeric columns are available for the numerical field selector. Features with missing, null, or non-finite values in a given field are skipped for that field’s statistics.

Available Statistics

The algorithm dialog provides checkboxes for selecting which statistics to compute. Only the selected statistics are computed, so deselecting the median and MAD (the costly measures) speeds up large runs.

Statistic	Description	Default
Sum	Sum of values	On
Mean	Mean of values	On
Count	Number of data points	On
Median	Median of values	Off
Variance	Variance of values	Off
MAD	Median Absolute Deviation	Off
Max	Maximum value	Off
Min	Minimum value	Off

Each statistic produces one column per field per distance threshold. All statistics use the decay function to weight contributions by distance; the default is flat (no decay).

Output

The output is a line layer with the original street segments and computed statistics as attributes. Output fields follow the naming convention:

cc_<field>_<statistic>_<distance>[_ang]    -> computed statistic

For example, with a price field and distances 400,800:

• cc_price_sum_400, cc_price_sum_800
• cc_price_mean_400, cc_price_mean_800
• cc_price_max_400, cc_price_max_800