Making a heat map from a Custom Arcade Expression?

Question

How can I make a heat map from a calculated Arcade Expression in AGOL? I am pulling in a point data set from the Living Atlas and using an Arcade expression to calculate a new attribute. When select the Custom Attribute, the Drawing Style for Heat Map disappears. Is there a way to make a heat map from this attribute? The Heat map options appears for other  attributes.

Thank you

JessicaBeres · Answer

Thank you Mike. Yes, adding a new field will not work for this situation. I am using the Live Stream Gauge feed from Living Atlas, to calculate the percent of flood stage for specific sites. We were hoping to be able to use this value to generate a heat map to predict other flooded areas. Since the data is constantly updating, creating a static data set will not be useful. Thank you for the help.

MikeMinamiP1 · Answer

The heat map drawing style doesn't support using custom arcade expressions as the attribute. We don't support it at this time. With hosted feature layers, you can add a new field and use an arcade expression to calculate a value into that field, then use that field as the attribute. However, this may not work in your case as it seems you are using a living atlas layer.

Calculate field values—ArcGIS Online Help | ArcGIS

Mike