View source for 6.3 Creating a New Scenario

[[Category:6.0 Configuring a Scenario]]


<p>The NERPM-AB catalog has a Master scenario, and scenarios are hierarchical
in nature. From the Master, you can create scenarios that will appear as
children of the Master. A child may be considered as a variation on its parent.
You can also create children of the preexisting scenarios, such as
Base2010.</p>

<p>A child scenario will inherit key values from its parent. For example, a
catalog may have some keys, one of which is named “Year.” This may be set to 10
in the Base2010 scenario. If a new scenario “New Road” is created as a child of
the Base2010, then the new scenario will also initially have a value of 10 for
the Year key. You may then edit the “New Road” scenario, updating the value of
Year to 15. You may choose to update some of the other keys of the scenario, or
you can leave them the same as in the Base2010. Running the “New Road” scenario
will substitute the value of 15 into the application for the Year key, giving
new results and providing a comparison with the base situation.</p>

<p>• To add a child scenario, click Add Child on the Scenario ribbon tab. Or,
right-click under Scenario in Scenario Manager and choose Add Child.</p>

<p>An Edit Box opens where you type the name of the new child scenario. To
cancel the operation, press ESC. To complete and save the name entered, press
ENTER.</p>

<p>After the name is entered, the Scenario Properties dialog is displayed to
allow entry of the scenario code, and then the Edit Scenario dialog will also
be displayed. This allows entry of the key values for the new scenario. An
additional modification has been made to NERPM-AB so that the first step of the
model process is to copy all of the input files from the parent scenario in the
child’s input directory.</p>

<p>If modifications need to be made to the scenario inputs before running the
new scenario, then the Prepare Data Folders step can be run manually to copy
the inputs. First, the NERPMAB1 App flow chart should be visible with the new
scenario active as shown in Figure 6-1. If the new scenario is not active, it
can be activated by selecting a different scenario and selecting the new
scenario again. Then the &quot;Prepare Data Folders&quot; <span style=
"color: rgb(38,38,38);">step can be run by itself by double-clicking on that
PILOT step pointed to in the following image. The input files will be copied
and can then be edited using the standard Cube tools.</span></p>

<p><strong><span style="color: rgb(38,38,38);">Figure 6-1 App Flow
Chart</span></strong>
</p>

[[File:Figure 6-1.png]]


<p>
</p>

<p>One important consideration when creating new scenarios is that Cube always
copies the key values from the parent of the new scenario. This is the case
even if the scenario is created as a &quot;sibling&quot; of an existing
scenario. For example, if the new scenario is created as a sibling of CF2040,
Cube will actually create the scenario as a new child of the parent scenario of
CF2040, inheriting the parent’s settings (Master in this case). Any new child
of Master will be identical to Base2010, and if another year is desired then
the appropriate network, land use, and key value inputs with need to be added
to the scenario manually. The inheritance process will be applied to any
scenario created as a child of one of the existing scenarios in that all inputs
and key values will be inherited from the parent. Any scenario specific changes
for the new scenario need to be applied after creating the scenario and running
the Prepare Data Folders step.</p>

<p><em><strong>Create a Master Network Alternative</strong></em>
</p>

<p>If roadway network changes are needed for the new scenario, or a new year is
being used, then a new alternative should be created in the Master network.
This is needed because NERPM-AB uses a single master net file for all
scenarios. The network alternative is specified by the scenario key values for
Alt and Year. The <strong>Create an Alternative</strong> app in NERPM-AB can be
used to create the needed alternative specific fields in the master network.
Care must be taken in modifying the network to avoid making unintentional
changes to other alternatives. Additionally, several files in the scenario
input directory include the Year and Alt in their file name, so the names must
correspond with the scenario Alt and Year keys.</p>

<p>Follow these steps (as illustrated in Figure 6-2)</p>

<ol>
<li>Select the <strong>Create an Alternative</strong> app in the App section of
the scenario manager</li>

<li>Double-click on the scenario for which you want to create a new network
alternative</li>

<li>Specify the key values for the new and existing alternative letters and
years</li>
</ol>

<ul>
<li>WARNING: If the new alternative letter and year correspond to an existing
alternative in the master network, then they will be replaced running this
app.</li>
</ul>

<ol>
<li>Click on the Save button and then the Run button to create the
alternative</li>

<li>Click on the Close button to exit Create an Alternative</li>

<li>Select the <strong>NERPMAB1</strong> app in the App section to return to
the main model</li>
</ol>

<p><strong>Figure 6-2 Steps in Creating a New Scenario</strong>
</p>

[[File:Figure 6-2.png]]