Express Yourself (and your data!) with Arcade Expressions

A quick recap of an Arcade demo at the 2019 Esri UC

Jennifer Bell

At the 2019 Esri User Conference, I presented a demo theater titled "Express Yourself (and your data!) with Arcade Expressions." Arcade is one of my favorite things to demo because people immediately start to see how they can easily use it to solve their current data issues.

The demo started off with a story  "How to Smart Map: Arcade" , created by Lisa Berry, introducing what Arcade expressions are and how to use them.

Arcade transforms your data values on-the-fly and can be used for your map symbology, labels, transparency, pop-ups, and symbol rotation. Do basic calculations, convert field types, and even create complex equations using your data. All without leaving the map.

The rest of the presentation included demos of how and where you can use Arcade. The demo started off with beginner-level examples and progressed to more advanced examples.

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Edit Labels

The first example map showed school district names in all caps.

With Arcade we converted a district like "STRASBURG SCHOOL DISTRICT' to proper text "Strasburg School District".

Here's the simple expression which uses the Proper() function on the "Name" attribute:

Proper($feature.NAME)

View map  here .

Convert Units

The second map showed live stream gauge measurements of stream height in feet.

This expression was created to convert the height in feet to meters:

$feature["stage_ft"] * 0.3048

Since 1 feet = 0.3048 meters, multiplying the "stage_ft" attribute by .3048 returns the height in meters.

View map  here  (ArcGIS Online login required).

Create Categories from Numbers

This part of the demo took the perspective of an employee tasked with charging e-scooters.

To help the employee prioritize which scooters to charge first, this expression created 3 categories of battery need.

var battery = Number($feature["battery_level"])

When (battery < 50, "Charge immediately", battery >= 50 && battery < 90, "Charge when able", "Fully Charged")

View the map  here .

Count the Number of Points in an Area

This example showed how to use FeatureSets to count the number of crimes in each police beat, all on-the-fly.

//This is where the polygon layer (police beats) makes a call to the points layer (crimes)

var crimes = FeatureSetByName($map,"Crime in the last 60 days")

//Counts the number of crimes that intersect with the police beats layer 

var countCrimes = Count(Intersects($feature, crimes))

//Return the result of the variable created in the line above

countCrimes

Click on the map to view the result of the expression in the pop-up.

View the map  here .

Make Pop-Ups Match the Map

This was the most advanced example that was covered. It shows a specific image and color in the pop-up depending on which country you select.

It also creates an ordered list that changes depending on the country.

Click on the map to view the result of the expression in the pop-up.

Click  here  to view the 3 expressions used in the pop-up.

I ended the demonstration with another story titled  "Can Layers Talk to Each Other?"  which provides detailed instructions on using Arcade FeatureSets.

View the story  here .

There were lots of great questions after the presentation ended. Here are a few of them.

FAQ

Where can we use Arcade?

  • Symbology
  • Pop-ups
  • Labels
  • Transparency
  • Rotation
  • Attribute table
  • In ArcGIS Online and in ArcGIS Pro

I like to think of simple Arcade expressions as easy Excel functions like sum, absolute value, etc. The more complicated expressions have similar logic to other scripting languages which makes it easy to learn.

Does Arcade work on layers that you don't own?

Yes! One of the biggest advantages that Arcade has is giving you the freedom and flexibility to work with any dataset, even if you don't own it.

Does Arcade work on live feeds?

Yes. Since Arcade recalculates values on the browser, and on-the-fly, it is especially useful when working with live feeds or datasets that change frequently because it automatically updates whenever new values come in. Arcade is a huge time saver.

Does Arcade FeatureSets work with tables?

Yes, a feature layer can bring in information from another table in the map.

Whether you're intrigued, interested, confused, or just excited to learn more, check out the Arcade resources below.

Additional Resources

Can't wait to share all the new and fun Arcade additions with you at next year's UC!

- Jen Bell

View the story  here .