Importing shape and GeoJSON files

During import, the information contained in the file is read into a Visum network. Which network object it is imported to depends on the type (point, line or polygon) in case of shape files, and by which processing mode (additive or non-additive). GeoJSON also distinguishes between different geometry types (Point, LIneString, MultiLineString, MultiPolygon), although the specific definitions may differ. In contrast to the import of shape files, the import of GeoJSON files is always additive. An overview of which shape file types or GeoJSON geometry types are imported to which network objects is provided by Table 281.

Table 281: Reading shape files in Visum network objects

 

Link, Screenline, Connector

Zone, Main zone, Territory, Main node

Node, Detector, Count location, Stop, Stop point

Points of interest

Point

 

X

X

X

Polyline

X

 

 

X

Polygon

 

X

 

X

Note: Creating POIs is only possible with additive reading , because a POI category has to be specified, where the POIs can be included. At least one POI category has to therefore be contained in the network, to read files as POIs.

Connectors, stop points, and count locations can only be read in additively.

To import point objects from geodata, you must first read them in as nodes and then use the "Aggregate isolated nodes" function to create stop points. In doing so, you also create the corresponding stop areas and stops (Using Visum: Aggregating isolated nodes).

While reading polylines as links, you can create alternative directed links or links with both directions. If a link is undirected, it has to be determined how to interpret each attribute.

  • Forward: direction from node ... To node
  • Backward: direction to node ... From node
  • Undir. value: 50% of the value for each direction
  • Symmetrical: equal value for both directions

While importing , you can determine which source attribute (from the shape file) should be assigned to which target attribute (an existing or user-defined attribute of the selected network object). The Illustration 221 shows an example, where shape file data is read as a link. The shape file contains the attributes STREET_NAM, LENGTH and LANE, which allocate the Visum link attributes Name, Length and Number of lanes.

Note: When loading polygons (e.g. as zone polygons or POIs for a background image), you can optionally activate normalization of the loaded surface data (Multi-part surfaces). This is required if you want to use the loaded polygons to perform geometrical operations, such as surface calculation or intersections, as otherwise the results might be falsified. If you merely wish to display polygons, then normalization is not required.

Illustration 221: Source and target attribute allocations

Example applications
  • Importing geodata from shape or GeoJSON with a road network as links in Visum. In Visum a routing-enabled link network is then available.

Note: The links have to first be enabled for transport systems.
  • Reading cross-communities as territories
  • Reading schools as POIs
  • Reading land use as POIs

In addition to importing shape and GeoJSON files as Visum network objects, you can also insert these files as a background. This is how you can insert land use (for example residential areas, industrial areas, commercial areas) to make your network more visible, for example. You can thus insert multiple shape file layers into the network (for example a layer for industrial areas). The drawing order of the layers and its color can be changed. The Illustration 222 shows an example, where two shape files were integrated as a background with land use for residential and commercial areas.

Illustration 222: Land use from two shape files as background