# Flow maps with trips

This part of the program is used to produce flow maps from origin-destination trips matrices generated by the transport model. The only way to be here is to specify in the previous window a valid shapefile with polygons representing the zones in the model. The user is responsible for a perfect match between the zones in the model and those in the shapefile. If, however, there is a zone in the model that is not in the shapefile, they will simply not appear in the maps. This may be useful for special zones, like external zones that you don't want to include in your maps.

In this manual we are using the model of Swindon as an example. This model and all related data may be downloaded from:

TRANUS site

To begin the process, a window called New Matrix Layer is presented with boxes to fill:

Matrix layer window.
Matrix layer window, Method color.

In (1) the list of all transport categories that were found in the data is displayd. In (2) and (3) the list of zones that was found in your data is listed. In (4) and (5) show method will use to show the results of the program.

### New layer name

Give a name to the layer you are generating, an obligatory field. The program will use this name to generate an auxiliary file in the Project Folder, so that you cannot use special characters that Windows will not accept as part of file names, such as ? * etc.

### Expression

The values to be mapped are defined in this expression. The expression may contain one or several categories added together. Double click the ones you want in the list to put them into the Expression box. Click on 'All' to define the sum of all categories.

### Origin/Destination

In the list of origins select one, several or 'All', and similarly in the list of destinations. This will generate a flow map of one-to-many, many-to-many, all-to-all, etc., zones.

### Scenarios

It is also possible to generate a map that relates trips that result from Expression for two different scenarios. For example, you may want a flow map with the growth of home-to-work trips from 91A to 16T. Double-click all home-to-work categories to put them in the Expression box, then select 16T from the Base Scenario pull-down, then select an operand, that may be - or /, and then choose the 91A scenario for the Alternative Scenario pull-down box. The program will subtract 16T - 91A, and this value will be used to generate the flow map.

### Method

Defines the method that will be used to show results of the model. There are two options, Color or Size.

### Some examples:

This will produce a flow map with the total number of trips for scenario 91A

- New layer name: Total trips 1991

- Expression: HWHigh + HWMed + HWLow + Serv + Educ

- Base Scenario: 91A

- Alternate Scenario: (nothing)

This will produce a map with the growth in the number of work trips from 91A to 11T

- New layer name: Total work trips growth from 91A to 11T

- Expression: HWHigh + HWMed + HWLow

- Base Scenario: 11T

- Alternate Scenario: 91A

- Scenario operand: -