topic Re: Custom Arcade symbology and symbol classes without features in ArcGIS Pro Questions

Custom Arcade symbology and symbol classes without features

AleydisG__Pere — Wed, 12 Feb 2020 09:42:42 GMT

I am using symbology classes defined by a custom Arcade expression.

My problem is that if there's no feature that satisfies some of the defined classes those symbols will not show in the Classes tab and therefore I can't format the symbol for future features that will fall in that class.

This is an excerpt of my Arcade expression:

if (Left($feature.KEY, 2) == '01')
{return "Oak";}
else if (Left($feature.KEY, 2) == '02')
{return "Palm tree";}
else if (Left($feature.KEY, 2) == '03')
{return "Cherry tree";}
else if (Left($feature.KEY, 2) == '04' || Left($feature.KEY, 2) == '05')
{return "Pine";}
else if (Left($feature.KEY, 2) == '07')
{return "Ash";}
else if (Left($feature.KEY, 2) == '08' || Left($feature.KEY, 2) == '09')
{return "Beech";}
else if (Left($feature.KEY, 2) == '10')
{return "Cedar";}

Right now we have no catalogued Ash nor Cedar, so there's no feature with KEY values starting with 07 or 10, but we will eventually in the future and need to format a symbol for those symbol classes.

As you see below, those classes do not show in the Classes tab and the 'Add unlisted value' option doesn't list those symbols either.

I thought of adding some dummy features with the missing KEY values to be able to format their symbols but I don't have the privileges to add features to the catalogue feature class, so I don't know if that would work anyway.

Any idea of what to do?

Re: Custom Arcade symbology and symbol classes without features

XanderBakker — Wed, 12 Feb 2020 12:55:31 GMT

Hi DMS2 ,

Have you tried adding the missing values?

Re: Custom Arcade symbology and symbol classes without features

AleydisG__Pere — Wed, 12 Feb 2020 14:08:38 GMT

Clicked that option and it turned grayed out.

Re: Custom Arcade symbology and symbol classes without features

XanderBakker — Wed, 12 Feb 2020 14:45:32 GMT

Hi DMS2 ,

That wasn't supposed to happen. I will try and test something here to see what happens. In the mean time, maybe Kory Kramer‌ may know something....

Re: Custom Arcade symbology and symbol classes without features

DanMakridakis1 — Fri, 25 Feb 2022 00:46:11 GMT

Xander, did you ever find a solution for this? I am dealing with the same issue. Trying to create a bunch of custom symbol values for data collection layers that currently have no records that satisfy the custom symbol expressions. As a result I'm getting no symbols and they aren't automatically appearing after records do satisfy the expression.

Is there an arcade expression for defining the different symbology values/classes regardless if they return any records? Something that would force them all to show?

Re: Custom Arcade symbology and symbol classes without features

LisaMcAleer — Tue, 19 Jul 2022 22:52:14 GMT

Has anyone figured this out??????? Sharing would be much appreciated!!

Re: Custom Arcade symbology and symbol classes without features

Dwight — Wed, 20 Jul 2022 13:22:47 GMT

For whichever combination of attributes you would potentially want to display add a feature expression in your web map for each value you would want shown just keep adding on to the framework, present and future sample below:

var status = $feature["STATUS"]
var type = $feature["TYPE"]

if ((status == "Value_Status_1") && (type == "Value_Type_1")) {

return "Status 1 - Type 1 Legend Label"
}

if ((status == "Value_Status_2") && (type == "Value_Type_2")) {

return " Status 2 - Type 2 Legend Label "
}

else {

return "Other" }

Re: Custom Arcade symbology and symbol classes without features

LisaMcAleer — Wed, 20 Jul 2022 14:57:21 GMT

Hey Dwight, Thanks for responding. This seems to be pretty much what I currently have, I think. In my map, at any rate, it does not list any values that are not currently in the dataset. I can code for if (Status=="Dog") { return "WOOF"}, but it won't display the legend item WOOF in my legend list until I actually get a "Dog" feature in my data. And that's what we are all here looking to do: Display and symbolize potential features in the legend BEFORE those features actually exist in the data. I know this could be accomplished with a hosted feature dataset published from Pro, but the particular dataset I'm working with is hosted on our AGOL but the data is actually a live feed from a 3rd party vender application. Long story short, I cannot establish a domain (add values to a list) for my display field in AGOL, nor can I add items to the legend that aren't currently in the dataset. I'd like to avoid having to constantly go into AGOL and custom symbolize new data. I guess I'm actually trying to replicate some type of layer file with arcade so my data would be "pre- custom symbolized," but so far I haven't found a way to make that happen........ I should add that I'm currently working in AGOL Map Classic. Not sure if the new viewer has anything more to offer.

Re: Custom Arcade symbology and symbol classes without features

Dwight — Wed, 20 Jul 2022 15:53:58 GMT

I believe this functionality is only available with the new map viewer.

Re: Custom Arcade symbology and symbol classes without features

LisaMcAleer — Wed, 20 Jul 2022 15:57:05 GMT

Alrighty, Thanks, Dwight!

Re: Custom Arcade symbology and symbol classes without features

DanMakridakis — Mon, 25 Mar 2024 21:50:39 GMT

Lisa, the below solution may work for you in AGOL but I haven't tested it there. This however was my approach for when I encountered it in Pro:

It's been a minute since I was working on this same problem, but I believe my only solution was to create dummy records for every custom symbol while setting up the symbology. Each dummy record would be identified using a common value in a particular field. After everything was configured you can then use a definition query on the layer to omit the dummy records based on that common dummy value (or by querying out their object ids). You can later delete the dummy records once a real record satisfices that expression.

--------

Another frustrating issue I constantly run into with the custom symbols expression, is that they always reset any time I altered the symbol expression. I would spend all this time creating the custom expressions for them, then creating custom symbols for each category only for it all to disappear the second I altered anything in the expression.

This was particularly annoying for a project where I had a different layer for all operators, each with the same custom symbol expression and symbols that would require updating. To prevent the need to redo the symbols for every layer when I wanted to change something, I created a python script which would regenerate the individual operator layers based on a template layer. The script would take the template and update the definition query and layer name based on a list of operator names. I would then only need to update a single template layer each time a change was needed. To keep this properly linked to my webmaps, the script would also assign a service layer ID to each layer.

Re: Custom Arcade symbology and symbol classes without features

LisaMcAleer — Thu, 21 Jul 2022 15:03:05 GMT

Thanks for your input, Dan. I think your suggestions would work if I were publishing my data from Pro into AGOL. But my data is actually a feed coming from a third party vendor that's published on our AGOL, so I can't publish or republish it. Data values will also come and go routinely, so a value that's there today may be gone tomorrow. I've been told that the new viewer may have more functionality, so I have to check that out. I will post anything I learn. Again, thanks for playing ; )