VISUM Tips & Tricks Archive

Editing the polygon of area objects

VISUM uses area objects for zones, territories, POIs, main nodes, main zones and toll systems, and offers a comfortable editor for their closed polygons. Are you sure to know all really helpful features available?

Memory RAM insufficient. What can you do?

In principle every new release is more demanding regarding memory. The aim is to get faster and getting faster more often is accompanied by an increase in memory consumption. When using multi core processors, data also has to be stored multiple times, for example. So what can you do to save memory or have more available memory?

1) Use VISUM-64-Bit

2) Application of the 3-GB-option of Windows XP

The 3-GB-option of Windows XP is also possible for other operating systems. Operating systems can be configured to allocate more memory to applications.

3) Using the matrices cache of VISUM

In order to use the matrices cache of VISUM in the menu "Extras->Options->Files&protocols->Matrices" you activate the function “Activate swap file“. The “Maximum size of matrix data stored in RAM” should be as small as possible.

4) Load matrix data if required

If you are working with many matrices but they are not needed immediately and at the same time, via the menu File->File properties “Lagged matrix data loading on demand” you can save memory. This setting is saved in the version file and will be executed when reading it the next time.

5) Execute with one CPU core

Several procedures require less memory if executed only with one CPU core (set under "Extras->Options->Environment").

Bar labels

Links have the attributes “Show bar text“ and “Bar text relative position”. These attributes may be changed for single links with "Show/Hide labels" (F4) and "Shift label" (F6). (Figure "Linkbar text")

Attribute “Show bar text” has a value of Yes/No respectively 1/0. If i it is set to “No”, no bar text will be displayed. IF set to “Yes”, the text will be shown if there is enough space.
“Bar text relative position” has the value 0.5 as a default, which means link bar will be labeled in the middle. BTW a link with shifted bar text will always show the text even if there is not enough space. You can therefore use it to force labeling.
Like other attributes they can be listed, filtered or set via Multi-edit. For Multi-edit also via “Special functions/Labels”. (Figure "Linkbartext_Multi-edit")
If links are digitalized (have graphical intermediate points) or there are many short links, labeling easy is left our because it no longer fits.
- A bar text doesn’t fit if its length is bigger than the distance between From Node and To Node.
- If there are many short links with two arm nodes, it’s possible to change these nodes to graphical points of links with Nodes->Multi-delete and “Connect links”.
- In the graphic parameters under Bars->Text format “along the longest section” is set as default. If “in the middle” is chosen instead, more shaped links will show the bar label.

: Linkbartext

: Linkbartext_Multi-edit

: "In the middle"

: "Longest segment"

Digitizing areas using catch points and zoom function

: Image 1

: Image 2

The Digitize mode ( e.g. of zone borders) does not allow you to zoom across the toolbar or move display details. The relevant function is greyed out (Image 1). From VISUM 11.5, however, you will be able to catch the points of common areas.

If too many points are too close to each other, you'd normally first have to switch to the Zoom mode again (Image 2). But now you can also zoom using the mouse wheel. If you want the mouse pointer to be in the focus while zooming, keep the CTRL key held down while turning the mouse wheel. You can also use the Page up and Page down keys for zooming. Use the arrow keys if you want to move the network.

Multi-editing attributes

: Image 1

: Image 2

: Image 3

There are at least 3 ways to change all or all active attributes.

To multi-edit network objects directly, from the shortcut menu, choose "Multi-edit".
(Image 1).
If you want to use a procedure, choose the "Edit attribute" function. Since procedures are saved as procedure parameters and these are saved with the version data, you can reuse them without having to enter them again. (Image 2).
Add-in (under Scripts/VisumAddIn)
The "Multi-edit attributes" add-in provides the widest range of functionality. Besides offering predefined functions, it allows you to use your own, complex functions. By including your own functions in a procedure, you also save them. (Image 3).

Keep an eye on 64-bit compatibility

Every now and then we receive inquiries from users who find that the Python scripts they used successfully under VISUM 32-bit no longer work under VISUM 64-bit. In our experience the reason is in most cases that the script uses a Python library which is not yet available in a 64-bit version. Two typical cases are GDAL (for GIS functions) and tkinter (for graphical user interfaces). In the case of gdal we hope that the ongoing effort in the open source community will soon produce a stable 64-bit version, which we will then make available for VISUM. In the case of tkinter we urgently recommend that you implement the graphical user interface in wxPython instead. There is no indication that a 64-bit port of tkinter is forthcoming, and wxPython GUIs conform more closely to the Windows look and feel. All of the add-ins that come with VISUM now use wxPython. If you still observe error messages pointing to tkinter, it is an indication that your installation is not up to date and applying the latest service pack should fix the problem.

User-defined attributes

: Figure 1

You can now create user-defined attributes even easier and quicker, namely via the shortcut menu (fig. 1)

For attribute selection, the user-defined attributes are highlighted with a dark red circle.

Filter in lists and timetable editor

: Figure 2

You can now set filter conditions in the Timetable editor with the click of a mouse button, e.g. when the Quick view and Overview window are hidden:

Right-click to go to the Filter dialog
(fig. 2)

Difference network/ Version comparison function

: Figure 3

The "Difference network" allows you to compare two networks and show the differences between them.

From VISUM 11.5, this procedure is simplified with the introduction of the "Version comparison" function (fig. 3).

Using the "Version comparison" function, you can edit the network and perform procedures (not so in the Difference network mode).

Adopting graphic parameters for link bars

Link volumes can be graphically displayed as link bars. You can now adopt user-defined settings made for one bar for other bars, so that you need not specify the same settings again (fig. 4):

Click the [+] button to copy the current settings of a bar and adopt them for other bars

: Figure 4

OD pair filter

: Figure 5

The OD pair filter is fundamentally different from the network object filter, since it filters origin-destination pairs between zones and cannot be used to set network objects active or passive. In the graphic display and in lists, the OD pair filter has an effect on all volume skims.

Flow bundles and turn volumes
Volumes of links, connectors, turns and PuT lines
Boarding, alighting, and transfer passengers at stops

You now have the option to switch off the recalculation of network volumes (see figure 5).
You can e.g. use the filter (without the recalculation function) for the following:

Shortening of OD pairs list
Filtering paths of a path set
Procedures with filtered OD pairs:
*PuT assignment
*Combining matrices and attribute vectors
*Trip distribution
*Assigning a matrix to paths
Saving matrices as partial matrix in O format

Comparative operators in filter conditions

: Figure 6

Within a filter condition you can now also use brackets and comparative operators, e.g. Attr1 < Attr2

Column diagram

: Figure 7

There are now some useful features available for displaying data in a column diagram:

Negative values are shown as downward columns
You can set the number of decimal places for labeling
You can specify a minimum value: "No column for values <= x"

Mouse navigation within the network

The middle mouse button or mouse wheel allow you to temporarily switch to "manual" mode.

"Check network" feature in VISUM

Easily forgotten and overlooked, but extremely powerful and helpful the "Check network" feature (Calculate menu) in Visum.

You can use it to check for mistakes or weak spots in the network. The results of the check are written to a file that you can view directly in Visum. It is convenient that after the check you can fix the problem immediately or quickly check "suspicious" network elements by setting them active. All other network elements become passive, thus enabling you to highlight these network elements graphically or list these seperately.

: This is the "Check network" dialog

: With “run tests” the network check is performed. After this, a symbol is displayed next to each topic that shows the status of the check

: If it is not marked with "OK", but with an exclamation mark, then errors were found. After clicking a “!”-button, a dialog like this opens, enabling a quick investigation (“Set to the active state”) and even to fix the problem immediately (“Delete”)

: If you leave the "Check network" dialog, you are asked wether you want to view the error log

Speed up version file loading by using the matrix swap file

: Image 1

: Image 2

Since VISUM 11.02-02 on loading a version file, VISUM can optionally load any contained matrices on demand, i.e. leave their data in the version file until they are actually accessed.

This will speed up version file loading, especially if you do not need the matrices for what you are about to do with the model, for example only view volumes in the network.

Using this option, the time VISUM needs to read additional matrix data, does not effect the performance.

In order to benefit from deferred loading you need to activate this behaviour per version file:

Start VISUM and make sure the matrix swap file is activated: Options => Files & Protocols => Matrices => Activate “Enable matrix swap file” (image 1). (Tip: 512Mb is the default value for the maximum size of matrix date stored in RAM, but you can choose a very small value too.)
Load the version file.
File => File properties => Activate “Lagged matrix data loading on demand” (image 2).
Save the version file. This might in some cases take a little bit longer.

The effect with version files holding numerous, large matrices might reduce the loading time up to 90%.

Google Maps Add-In

This add-in allows you to visually inspect the surroundings of a network node or main node in Google Maps. This can be a handy shortcut, if you wish to check the correctness of the junction model.

Method

The add-in calls up a satellite map of the surroundings of the node or main node in Google Maps and displays the result in your Web browser.

In order to convert the position of the node to latitude / longitude, VISUM needs to know the projection used for the coordinates in your model. Be sure to set the projection under Network – Parameters before using the add-in. In some cases the third-party library used for the reprojection fails to convert from the VISUM projection to lat/long. In those cases you can try switching manually (in Network – Parameters) to WGS_1984. Don’t forget to switch back when you are done, if you plan to save your changes.

The add-in assumes that you have a Web browser installed on your computer and it is set up as the default program for files with extension “.htm”. You also need a connection to the Internet while using the add-in.

Parameters

Start by marking a single node or main node in the network editor.

Zoom level: A number describing how far Google maps should zoom in to the coordinates of the node. A level of 19 usually results in a view that is detailed enough to see lane markings etc. if present. Use a lower number if Google complains that it does not have maps down to this resolution, or if the coordinate match is less than perfect.

Click Display to show the map for the currently marked node or main node. The window will remain open, so you can mark and display further nodes. Click Close when done.

Import GPS Points

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: Image 2

: Image 3

: Image 4

Customers often ask us how GPS points in WGS84 can be imported in VISUM. The simplest way is, by saving a small network file and supplementing the point data by the column format NO;X-Coordinate;Y-Coordinate.

This is how it works:

Start VISUM.
Set the desired coordinate system: Network -> Network parameter -> Coordinate system -> Radio button "from file" -> Button "..." -> Dialogue projections -> Geographic Coordinate Systems -> World -> GCS_WGS_1984 / WGS 1984.prj -> Ok -> Ok.

(If the coordinate system is double-clicked, the projection dialogue is closed automatically.)

Insert a node.
Save as a network file (File -> Save as -> File type selection -> Networks)
In the dialogue "Save network" activate the button "All tables OFF" and only activate the object types network parameters and nodes.
Under "Node" make all fields visible and deactivate all fields except NO, XCOORD and YCOORD. (image 1)

(Admittedly this is laborious. Did you know that in the dialogue, you can navigate using the arrow keys and activate or deactivate entries using the space bar?

Of course you can also save a layout and keep it for later.

Tip: Did you know, that a network file is also written, where only the buttons of the table are included? These can also be changed very easily with a text editor.

Exit the dialogue with OK.

The file created can be opened with a text editor. The only row under the header "$Node…" codes according to the column format

NO;X-Coordinate;Y-Coordinate
and can be replaced by other rows with the same format. (image 2)

Attention: The number groups of this node should not overlap with the number groups of the nodes in the version file, to which these nodes are written.

In principle POI objects can be used instead of nodes, but in this case a POI category has to be created first. In the dialogue "Save network" activate the object type POIOFCAT_1 and the column format looks slightly different.

The contents of this network file can now be added to a version file:

Open the VISUM version file.
First set your coordinate system of your network file to WGS84 (see Point 2).
Then read the network file: File -> Open -> File type selection -> Networks -> Specify file name and location -> Read dialogue network -> Read network file additive -> Additionally read dialogue network data -> OK.
Finally set the coordinate system back to the original system. (image 3)

Tip: The now read nodes can be displayed via the graphics parameter and filter their properties as isolated nodes. To do so, create a filter with the attribute NumLinks and the value range up to 0. (image 4)

Any questions? Visum.Hotline@ptv.de

Additive reading of network files

If you want to add further network data to an existing network in VISUM, without losing the existing data, these can be read in additionally with the following steps:

The network data which you want to add, has to be in ASCII format "Networks" *.NET (therefore no version file)
MENU: File -> Open -> File type select "Networks" -> ok
Select the corresponding file to be read additionally
Activate the button "Reading network files additionally"
If the button "First off, determine tables in file" is active, the network file is first read, so that it can be displayed for the user, which table is contained in the network file.
Tables can now be selected for adding.
If a network element already exists which should be added (e.g. Node 100 already exists), different options can be selected for conflict handling:
- The new information is ignored
- The network element attributes are overwritten
- The network element object is overwritten. This means, that the network element is first assigned with standard attributes and the new attributes are then read.
- If the network element already exists in the existing network, additional reading can be canceled.
Furthermore, conflict avoidance can be activated in the same window "Read network data additionally". This would mean, that a new element always has to be created, which then however receives a different relation (for example Node 100 is added with a predefined offset, in order not to occur twice).

Reading graphic parameters selectively

The graphic parameter setting is as desired, but you want to take on a part from other parameters.

MENU: Select File -> "Open graphic parameter"
Select the corresponding graphic parameter to be added
Switch from "Read all graphic parameters" to "Read selected parameters"
Blocks of information can now be selected to be read, such as window section, link bars and print area.
The other settings remain unchanged.

Reading and summing up matrix values

It is assumed here, that there are several values for a relation in the matrix and the values should now be summed up.

To do so:

The matrix file has to be in ASCII format "$O" (Row : FromZone ToZone Value) and
the button "Treatment of multiple nominations in $O matrices" should be set under
MENU: Extras -> Options -> Files & Protocols -> Matrices as desired, or
in the matrix editor via the symbol "Global settings" in the "Matrix input" tab.

Editing more than one network object at a time

It has been possible for a long time to set network elements as active and inactive via the filter or spatial selection and then set an attribute for all active network elements with multi-edit. Since VISUM 10 editing several objects of a network object type can also be carried out for all marked objects (Chapter 4.2.2.1 in the manual). Several elements can be marked by pressing the Ctrl button. With a right-click in the network window you can then select change, remove and other editing functions. When having the "Quick view" window open (see View/Toolbars, Chapter 3.3.3), you can see and edit the attributes of the currently marked objects. Several attributes can also be copied and changed for all marked objects.

New OD pair list

In the new OD pair list for example, you can list the values of all demand matrices next to each other. This view may be more practical than having several matrices open in the matrix editor. With a right-click with "Search...", you can enter FromZone and ToZone and thus come directly to the respective row.

Switch link bar labels

The bar label at links can be switched off or moved individually for each link. Whether the text is switched on or off, it is regarded as a Boolean value ( 0 = no, 1 = yes) in the attribute "ShowBarText". The shift position is in the "BarTextRelPos" and lies between 0 and 1. As link attributes, these values can also be edited, filtered and listed with multi-edit.

How to choose an appropriate coordinate system

Learn more on this tip and trick here (PDF)...

How to add a correctly georeferenced GoogleMaps aerial image

Click here to read this tip and trick (PDF)