When multiple processes share the same user input parameters or pre-defined values, specific values can be set in advance, either for a single process, or shared between processes, and saved in the model file.
The “New value” command creates a new Value object linked to an input connector on the process tool it relates to. This Value can be shared with other processes.
If a particular process requires specific input when the model file is run, the “New parameter” function will add a Parameter object to that process tool. When the process model file is run, the parameter is displayed as a field in the Run dialog box. This will prompt the user to identify or point to the required input. A single parameter may be shared between processes.
Default Parameters
You can add default options to a parameter if you expect that it will generally use the same options. To create a default:
1. Click on the parameter.
2. In the Parameters window, under the Default Control State section, click on the square to the right of the option and click “Add Default”.
3. Set the options to the desired default values.
When the process is run, the options for this parameter will be set to the default values. The user of the process can still override the default options if they choose.
Automatic Parameters
Some processes, such as Classify Points for Cartography and Render Raster, have default Automatic options for their coverage and/or band parameters. If these fields are given as parameters, then when the process or process model is run in the application, the values automatically use the coverage or band that is currently selected in the application as input to the parameter. If the selected coverage or band is not relevant, the first relevant open coverage or band is used instead.