# Capture Values

When creating a new feature in Roam you can pull values from another layers using a default expression on the field.

Setup the default expressions using the config manager

• Open Config Manager
• Select the Project and Form
• Select the field
• Update the expression tab to be Capture value from field
• Set the Capture Layer to the layer to take the value from
• Set the ** Value Field** to the field which has the value you need
• Set the Expression to a QGIS expression that will test if to return the value or not

# Common Expressions

• intersects($geometry, buffer($roamgeometry, 5))
• within($geometry, buffer($roamgeometry, 5))

$roamgeometry is a reference to the currently selected feature when the expression is run. This is the feature being edited or created when the form is opened.

# How it works

When Roam creates a new feature the expression is tested against every feature within view to see if the expression will match.

Note: The first matching feature is used for the value and there is currently no UI control to pick other values