2025-03-10 TIL: Arcade Expression

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ArcGIS Arcade

ArcGIS Arcade, a basic scripting language from Esri, helps you map the values you need or create completely new data values in minutes.

Arcade is a portable, lightweight, and secure expression language used to create custom content in ArcGIS applications. Like other expression languages, it can perform mathematical calculations, format text, and evaluate logical statements. It also supports multi-statement expressions, variables, and flow control statements.
Arcade’s power lies in its portability across different ArcGIS applications. It provides a consistent syntax that can run on desktop, web, and mobile devices.

Example: Constructing an ArcGIS Earth App Link from a Feature Popup:

var geom = Geometry($feature);
var x = geom.x;
var y = geom.y;

// Handle the Z-coordinate, defaulting to 500 if null or empty
var z = DefaultValue(geom.z, 500);

// Function to convert Web Mercator to WGS84
function WebMercatorToWGS84(pt) {
    var x = pt.x / 20037508.34 * 180;
    var y = pt.y / 20037508.34 * 180;
    y = 180 / PI * (2 * Atan(Exp(y*PI / 180)) - PI / 2);
    return { 'x': x, 'y': y };
}

if (geom.spatialReference.wkid == 102100) {
    var coords = WebMercatorToWGS84(geom);
    x = coords.x;
    y = coords.y;
}

url = "[www.arcgis.com/home/item...](https://www.arcgis.com/home/item.html?id=7de2582460bb47e284b2adc5e6a6753b)";

url = UrlEncode(url)

var earthLink = "[earth.arcgis.app](https://earth.arcgis.app/?viewpoint=cam:)" + x + "," + y + "," + z + ";" + "" + "," + "" + ";&url=" + url;

return earthLink;