Analyze graphs

Graph networks can be analyzed by computing global integration, local integration, and in-between centrality. For each street, these values are computed and stored as object attribute integrationGlobal, integrationLocal, and inbetweenCentrality. The values can be visualized or used to approximate street widths.

To open the dialog box, select a set of graph segments or a graph layer and click Graph > Analyze Graph in the main menu.

Settings

The following table lists the setting for the Analyze Graph tool:

Mode	Three modes are available: Calculate analysis only (as object attribute)—For each street, the three analysis values, global integration, local integration and inbetween centrality, are computed. These values are stored as object attributes. Visualize analysis (assign rule)—Computes the three analysis values and assigns a visualization rule file to the street shapes. Model generation is automatically triggered. The visualization can be configured by selecting street shapes and using the Inspector. Set street width (based on integration)—Computes the three analysis values and maps the local integration to the range specified by Street Width Min and Street Width Max. After running the tool, select the street layer to see or change the mapping code in the layer attributes in the inspector.
Depth of local integration	The number of 90-degree turns to take into account to compute the local integration value.
Roadbed lanes min	Roadbed lane width lower bound; it is only used in Set street width mode.
Roadbed lanes max	Roadbed lane width upper bound; it is only used in Set street width mode.
Sidewalk width min	Sidewalk width lower bound.
Sidewalk width max	Sidewalk width upper bound

Definitions

All shortest paths between all selected street segments are computed. The shortest path cost function is the sum of all angles between the segments along the path.

Global integration

For each street segment, the shortest paths to all other segments are summed up. Each sum is then divided by the square of the number of segments. Next, each value is inverted. Finally, the values are normalized so that each value is in the range zero to one.

Local integration

For each street segment, the shortest paths to all other segments which are closer than (Depth of local integration) 90-degree turns are summed up. Each sum is then divided by the square of the number of visited segments. Next, each value is inverted. Finally, the values are normalized so that each value is in the range zero to one.

Inbetween centrality

For each street segment, the number of shortest paths that pass this segment is computed. Then, the values are normalized so that each value is in the range zero to one.

Example

The global integration of a typical street network is shown.