Specifying settings for conflict avoidance and conflict handling

A conflict arises when a network object you want to read in and an already existing network object have the same key. In this case, Visum allows you to specify how to proceed for each data table you wish to read in.

Note: Key attributes are attributes which serve for unique identification of network objects (Key attributes).

Tip: To make the settings for several data tables at the same time, highlight the respective tables and then click the Edit button.

1. Select Conflict avoidance if you know that the network objects of your existing network and the network objects you want to read in have the same key, but are not identical.

Element	Description
Conflict avoidance	If this option has not been selected or if it is not provided, you can - in the Conflict handling column - choose how to handle network objects with identical keys. If this option has been selected, in the Conflict handling column, either a list with the options Offset and Compress with offset or Prefix is displayed. Selecting an option, you can change the value of the key attribute you want to read in, to make it unique. Prefix (In the Conflict handling column) To an alphanumerical key attribute, you can add an alphanumerical prefix in the first position. Offset (In the Conflict handling column) To the value of a numerical key attribute you can add a constant value. Note When specifying offsets, make sure that the offset values you define are added to all keys of the network object. Example: Link 1 has the following keys: link number 1, From node number 10 and To node number 20. If you specify the offset value 1 for links and 2 for nodes, Visum will read this link in as link number 2, From node 12 and To node 22. Note the following: If Visum cannot add the link because it cannot find To node 22, Visum will subtract the offset value from the To node and try to add the link with the To node number 20. Compress with offset Select this option to renumber all network objects of the type selected, starting with 1 up to the number of the network objects (N) before the network is read. Network objects that are added with 'Read network additively' are numbered starting with N + 1 up to the number of network objects of both networks (N+M). The field into which the offset is entered is not available. This option is available for network object types that can also be renumbered in the Program window, via the Edit menu (Automatic renumbering of network objects), as well as for the following network object types: Turn standards Ticket types Operating periods Vacation days Surfaces Time series Edges Signal controllers Matrices Demand time series Stage templates Stage template sets PuT operators PuT vehicle units PuT vehicle combinations PuT coordination groups PuT fare zones PuT valid days (special case valid day Daily that is always number 1) Signal group templates Signal coordination groups Fare systems Faces Line blocks (special case, here new IDs are assigned. Line blocks do not have a number.) Line block versions (special case, see line blocks) Fleet compositions Intermediate points

Element

Description

Conflict avoidance

If this option has not been selected or if it is not provided, you can - in the Conflict handling column - choose how to handle network objects with identical keys.

If this option has been selected, in the Conflict handling column, either a list with the options Offset and Compress with offset or Prefix is displayed. Selecting an option, you can change the value of the key attribute you want to read in, to make it unique.

Prefix

(In the Conflict handling column)

To an alphanumerical key attribute, you can add an alphanumerical prefix in the first position.

Offset

(In the Conflict handling column)

To the value of a numerical key attribute you can add a constant value.

Note

When specifying offsets, make sure that the offset values you define are added to all keys of the network object.

Example:

Link 1 has the following keys: link number 1, From node number 10 and To node number 20. If you specify the offset value 1 for links and 2 for nodes, Visum will read this link in as link number 2, From node 12 and To node 22.

Note the following: If Visum cannot add the link because it cannot find To node 22, Visum will subtract the offset value from the To node and try to add the link with the To node number 20.

Compress with offset

Select this option to renumber all network objects of the type selected, starting with 1 up to the number of the network objects (N) before the network is read. Network objects that are added with 'Read network additively' are numbered starting with N + 1 up to the number of network objects of both networks (N+M). The field into which the offset is entered is not available.

This option is available for network object types that can also be renumbered in the Program window, via the Edit menu (Automatic renumbering of network objects), as well as for the following network object types:

Turn standards
Ticket types
Operating periods
Vacation days
Surfaces
Time series
Edges
Signal controllers
Matrices
Demand time series
Stage templates
Stage template sets
PuT operators
PuT vehicle units
PuT vehicle combinations
PuT coordination groups
PuT fare zones
PuT valid days (special case valid day Daily that is always number 1)
Signal group templates
Signal coordination groups
Fare systems
Faces
Line blocks (special case, here new IDs are assigned. Line blocks do not have a number.)
Line block versions (special case, see line blocks)
Fleet compositions
Intermediate points

2. If you do not want to choose conflict avoidance, select an option for conflict handling.

Element	Description
Conflict handling (if Conflict avoidance is not selected or available)	Only check This setting is only available for specific elements, e.g. transport system, mode, and demand segment. Visum checks whether the network objects you want to read in already exist in the current network. If this is not the case, an error message is displayed and the reading in process is canceled. Ignore Ignored are those network objects in the network file being read that have identical keys which are already in use in the currently open network file. The existing network objects and their attribute values remain unchanged. Overwrite object/course Existing network objects for which the network file contains network objects with identical keys, are replaced by the objects read from file. Attribute values of attributes which are not contained in the network file are set to a default value. Overwrite attributes Existing network objects that have the same keys as objects in the network file remain unchanged. Only their attribute values are overwritten. Attribute values of attributes which are not contained in the network file remain unchanged. Overwrite structure If the network file contains lanes for a leg, they are overwritten. Cancel Reading is canceled.

Element

Description

Conflict handling (if Conflict avoidance is not selected or available)

Only check

This setting is only available for specific elements, e.g. transport system, mode, and demand segment. Visum checks whether the network objects you want to read in already exist in the current network. If this is not the case, an error message is displayed and the reading in process is canceled.

Ignore

Ignored are those network objects in the network file being read that have identical keys which are already in use in the currently open network file. The existing network objects and their attribute values remain unchanged.

Overwrite object/course

Existing network objects for which the network file contains network objects with identical keys, are replaced by the objects read from file. Attribute values of attributes which are not contained in the network file are set to a default value.

Overwrite attributes

Existing network objects that have the same keys as objects in the network file remain unchanged. Only their attribute values are overwritten. Attribute values of attributes which are not contained in the network file remain unchanged.

Overwrite structure

If the network file contains lanes for a leg, they are overwritten.

Cancel

Reading is canceled.

3. Confirm with OK.

It is checked whether the data on the system of coordinates of the network file are identical with those of the existing network. Depending on the constellation either a warning or a window opens or the data is read from file without any further query.

4. Make the desired changes, if applicable.

Coordinates data in the network file	Coordinates data in the network	Response when read in
None	Visum (no projection)	The coordinates are read without transformation.
None	From projection file *.prj	The Select spatial reference system window opens. Select the system of co-ordinates of the network file via option From file Visum transforms the co-ordinates of the network file into co-ordinates of the network. If you select the option Visum (untransformed reading) instead, the coordinates will be read from file without transformation. Confirm with OK.
From projection file *.prj	Visum (no projection)	A warning is issued. Confirm with OK. The coordinates are read without transformation. Note To match the data, it is generally recommended to first change the coordinate system of the network (Selecting a coordinate system).
From projection file *.prj	From projection file *.prj	The data is read without further queries. In case of different co-ordinate systems the co-ordinates of the network file will be transformed into co-ordinates of the network.

Note: If the Show the 'Completing line routes' window option has been checked, the Read network (completing the courses of line routes/system routes) window opens. Here you can specify how you want to add the data (Reading a network file with incomplete line routes or system routes).

The network data is read in. If you select the option Show statistics of modifications, the model transfer file with the changes made is opened. When you close this window, a query window is opened that allows you to save or delete the file.