GoMore Network AnalysisKate LyndegaardGEOG 596AMentor: Frank Hardisty
Outline
1. Motivation and summary2. What is network analysis?3. The project objective4. The GoMore network5. The preliminary results6. The next steps7. Thanks
Motivation and Summary
Motivation and Summary- How can we begin to discuss integration of spatial analysis and
social network analysis intersect?
- Are there elements of geospatial/geostatistical theory which complement social network theoretic approaches to examining context and relationships in networks, and vice versa?
Motivation and Summary- How can we begin to discuss integration of spatial analysis and
social network analysis intersect?
- Are there elements of geospatial/geostatistical theory which complement social network theoretic approaches to examining context and relationships in networks, and vice versa?
What is network analysis?
Network RepresentationA network represents data as a series of ‘nodes’ and ‘edges’
Node
Edge
Directed NetworksA directed network represents the directionality of events represented by ‘edges’
Weighted NetworksNot all networks are represented by edges sharing equal values.
Weighted networks attribute additional data to every edge.
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15
10
2
2
2
2
6
Topological Properties: DegreeCentrality measures such as ‘degree’ measure the relative importance of a node within a network.
Degree = 5
Out degree = 3
In degree = 2Out degree = 1
Source: Lotan, G.: Network X and Gephi, NYC PyData Conference 2012
Topological Properties: Path Length
Path length measures the number of edges between two nodes.
Shortest path length, and average path length (calculated over the entire graph), may also be measured.
12
45
3
6
Path Length = 2
The Project Objective.
Analyze the GoMore Network• Analyze the network of Northern Europe’s leading, online ride-share
provider: GoMore (www.GoMore.dk)
Analyze the GoMore Network1. Examine a number of topological network properties in
order to characterize the interconnectivity of GoMore travel
2. Examine weighted network properties in order to analyze the significance of the volume of travel
3. Determine whether or not there is a correlation between population density and the volume of travel between network nodes
The GoMore network.
Creating the Network Graph
Technologies employed:• PostgreSQL: Advanced SQL queries to structure data• Gephi: Generate .GML (graph file), visualization,
analyses• igraph as R package: Implement network analysis
algorithms• R: Implement statistical methods, visualization• ArcGIS for Desktop: Spatial analyses, visualization,
feature attribution, processing of demographic data
Creating the Network Graph: PostgreSQL
‘nodes’ table
Creating the Network Graph: PostgreSQL
‘edges’ table
Creating the Network Graph: Gephi
GoMore network graph: Circular Layout
Creating the Network Graph: ArcGIS
Creating the Network Graph: ArcGIS
The Preliminary Results.
Topological Properties of the GoMore Network
Comparative Model: Erdős-Rényi random graph
Power Law Degree Distribution
Clustering Spectrum: Average Local Clustering Coefficient vs. degree
Source: Barabási, A.L.: Network Science. Forthcoming, pp. 41
Average Nearest Neighbor vs. Degree
The Next Steps.
The GoMore Network and Population Data
Next Steps1. Complete and refine weighted network analyses
2. Refine spatial analyses
3. Discuss correlations between network and spatial analyses
4. Complete journal article for peer-review (GIScience 2014, Vienna, Austria)
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ThanksI would like to thank Beth King and Frank Hardisty