Executing processes using WPS Builder¶

Adding a process to the workflow¶

To add a process to a workflow, select it from the Process List and drag it onto the Canvas. The process block will be added in the location where it is dropped. Attached to it will be one or more input blocks, representing each of the inputs used to run the process. Also attached is a green block, often called result, for the output of the process. The block is only used when chaining to another process.

The ras:RangeLookup process added to the Canvas

To remove a process from the workflow, click the central yellow block to select it and press the Backspace or Delete key. You can also click the Clear button at the top of the screen to remove all processes from the Canvas.

Setting the inputs¶

Inputs used by a process are rendered in the canvas in two colors: light brown for those input parameters that are optional, and a darker brown for those that are required.

A required input and an optional input

If the parameter has correctly been assigned a value, the block will have a solid border.

A valid input

If the parameter hasn’t been assigned a value, or if that value is invalid, the block will have a dashed border.

An invalid/unset input

All of the required inputs must be assigned a valid value (and have a solid border) before being able to run a process workflow.

There are two ways of setting a value for a given parameters:

• Selecting/entering the value directly in the Inputs tab of the Input/Output panel
• Linking the input to the output of another process

To set the value for a parameter using a specified value, click the parameter name. In the Input/Output panel with the Input tab selected, you will see an element corresponding to the parameter where the value can be entered or selected.

The type of the element depends on the type of parameter. For instance, for a string or numeric input you will have a textbox:

Input textbox

For a vector or raster input layer, there will be a box where a layer can be selected from layers available in GeoServer.

Input layer select

When the input is a geometry, this can be generated by drawing a geometry in the map (via Map):

Map input

Or a geometry can be input via a text box, in either Well-Known Text (WKT) or GML (via Text).

WKT input

Once you have entered or selected a value, click the Save button. Some parameter types need to be validated, and this validation will be shown here.

Invalid input

Valid input

Certain parameters allow multiple values to be used. In this case, you will see a button named +1 [parameter_name]:

A parameter that can accept more than one value

Clicking this button will cause a new item to be added in the canvas as a parameter. Click the button as many times as needed, and then set the values of each of the new parameters individually.

Two additional “ranges” parameters added to the process

To link the input to the output of another process, make sure two processes are in the Canvas. Click the plug on the side of the green output block for one of the processes, and drag a wire to one of the inputs of the other process. If the connection is valid, the plug will be highlighted.

Chaining two processes

To remove a connection, click the wire so that it is highlighted, and then press the Backspace or Delete key.