2-4 Methods Part 2

Question 1

diameter of a graph

Answer 1

the length of the shortest path between the most distanced nodes of a graph. planar networks tend to have a larger diameter.

Question 2

path, chain

Answer 2

path: a sequence of links that are traveled in the same direction
chain: a sequence of links having a connection in common with the other

Question 3

circuit, cycle

Answer 3

A path where the initial and terminal node corresponds

A chain where the initial and terminal node corresponds

Question 4

complementary graph

Answer 4

two subgraphs are complementary if their union results in a complete graph.

e.g. multimodal transportation network

Question 5

dual graph

Answer 5

A method in space syntax that considers edges as nodes and nodes as edges. e.g. urban street networks showing hierarchical structures and the true connectivity in a planar network

Question 6

Tree and root node

Answer 6

tree: a connected graph without a cycle. nodes = links +1
e. g. river basins

root node: a node where every other node is the extremity of a path coming from it. e.g. the starting point of a distribution system, like a warehouse.

Question 7

articulation node

Answer 7

In a connected graph, an articulation node is by removing it, the sub-graph obtained is NOT CONNECTED.

E.G. a port which serves as a bottleneck

Question 8

isthmus connection

Answer 8

In a connected graph, an isthmus is a link that is creating, when removed, two sub-graphs having at least one connection.

e.g. the most central link in a complex network

Question 9

topological vs continuous measures of accessibility

Answer 9

1. measure accessibility in a system of nodes and paths. e.g. a transportation network. Accessibility is a function of the network structure.
2. measure accessibility over a surface. Accessibility is a function of the spatial structure.

Question 10

geographic vs potential accessibility

Answer 10

1. the accessibility of a location is the summation of all distances between other locations divided by the number of locations. the lower, the better.
2. the higher, the better. geographical accessibility weighted by the attributes of a location

• emissiveness: capacity to leave a location
• attractiveness: capacity to reach a location

Question 11

shimbel distance/index

Answer 11

for a given node, sums the length of all shortest paths to other nodes. It’s a measure of nodal accessibility