topic Re: Create a list with a data expression that creates a buffer of an existing feature in ArcGIS Dashboards Questions

Create a list with a data expression that creates a buffer of an existing feature

GIS_utahDEM — Wed, 19 Jun 2024 18:22:52 GMT

Hello! I am trying to create a data expression to populate a list in dashboards that reflects all the features of an existing featureset, but with a specific buffer around them. Mainly, I'm just not sure where in feature's attributes I can access/change the geometry and I'm having a hard time finding documentation about it. I currently have it on line 27 in the code below -- but I'm honestly not sure if that is where it would go OR if that would be the correct key to use.

var agol = portal('https://www.arcgis.com') var layer = FeatureSetByPortalItem(agol,'0ca544f09ff94130b2685fbcbb7f89f1'); var recalc = { 'fields': [{'name':'Name', 'type':'esriFieldTypeString'}, {'name':'objectid','type':'esriFieldTypeOID'}, {'name':'globalid','type':'esriFieldTypeGlobalID'}, {'name':'Type','type':'esriFieldTypeString'}, {'name':'Status','type':'esriFieldTypeString'}, {'name':'Date','type':'esriFieldTypeDate'}, // {'name':'search_date','type':'esriFieldTypeDate'} ], 'geometryType': '', 'features': [] } for (var a in layer) { var new_a = {'attributes':{ 'Name':a.Name, 'objectid':a.OBJECTID, 'globalid':a.GLOBALID, 'Type':a.Type, 'Status':a.Status, 'Date':a.Date, }, geometry:Buffer(Geometry(a),50,'miles') } Push(recalc.features, new_a) } return FeatureSet(Text(recalc))

When I "Run" it, I get a table with the appropriate attributes, but no shape field

Re: Create a list with a data expression that creates a buffer of an existing feature

GIS_utahDEM — Wed, 19 Jun 2024 20:00:25 GMT

Well -- I solved my own problem and it actually does work for filtering and such on the map...but I'll keep it here in case someone else wants to see how I did it!

Re: Create a list with a data expression that creates a buffer of an existing feature

HollyTorpey_LSA — Mon, 04 May 2026 23:37:40 GMT

@GIS_utahDEM Do you still have the code that ended up working? I'd love to see it.

Re: Create a list with a data expression that creates a buffer of an existing feature

GIS_utahDEM — Thu, 14 May 2026 18:56:11 GMT

The data expression ended up taking a really long time and frequently failed, so instead I have a hosted notebook that runs on a schedule to just create/update a separate buffer layer that has been added to the map and dashboard. You can see the code I used for the buffer creation here:

https://github.com/julia-surkis/SituationalAwareness/blob/main/IncidentPointsToBuffer.ipynb