Space syntax as traffic proxy

alan-turing-institute / spatial-inequality

MIT License

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Space syntax as traffic proxy #26

Open jack89roberts opened 3 years ago

jack89roberts commented 3 years ago

Check viability of using space syntax as a proxy for traffic

jack89roberts commented 3 years ago

Data source:

jack89roberts commented 3 years ago

Paper correlating space syntax with traffic:

https://discovery.ucl.ac.uk/id/eprint/10045014/ (Spatial Configuration and Vehicular Movement: a nationwide correlational study, Lage Alvim Serra, M; Hillier, W; (2017) )

jack89roberts commented 3 years ago

https://core.ac.uk/download/pdf/16255392.pdf

integration measures the distance from each spatial element to all others in a system (up to a certain radius and given a definition of distance), and so corresponds to mathematical closeness. Choice measures the quantity of movement that passes through each spatial element on shortest or simplest trips between all pairs of spatial elements in a system (again up to a certain radius and given a definition of distance), and so corresponds to mathematical betweenness. We often say that integration represents the to-movement potential of a space, and choice the through-movement potential, pointing out also that the two measures correspond to the two basic elements in any trip: selecting a destination from an origin (integration), and choosing a route, and so the spaces to pass through between origin and destination (choice)

jack89roberts commented 3 years ago

I think:

Axial map: Each road a node (edges are intersections and don't have lengths?) (relevant paper)
Segment map: Each line segment (road section between intersections, or curved road converted to straight segments) is a node, and each edge represents an intersection between line segments. Weight of edge can be Euclidean distance between segment end-points or angle between segments.

Might be helpful: https://core.ac.uk/download/pdf/198042859.pdf

jack89roberts commented 3 years ago

The angular segment choice is calculated by counting the number of times each street segment falls on the shortest path between all pairs of segments within a selected distance (termed the ‘radius’). The ‘shortest path’ refers to the path of least angular deviation (namely, the straightest route) through the system (Hillier and Iida 2005, p. 475)

https://link.springer.com/chapter/10.1007/978-3-030-59140-3_2#Sec14

jack89roberts commented 3 years ago

Angular total depth is the cumulative total of the shortest angular paths to a selected segment as root.

https://www.spacesyntax.online/term/angular-total-depth/

i.e. total angular "distance"/cost to get from anywhere to the line segment of interest.

jack89roberts commented 3 years ago

Normalised angular choice (NACH):

NACH  = log(ACH + 1) / log(ATD + 3)

where ACH is Angular Choice and ATD is Angular Total Depth. Constants are to avoid log(0) (e.g. for segments that don't appear on any shortest routes).