Add all Shape_Area in attribut expression in the contents of a layer's pop-up window on AGOL

Question

Hello,

I'm trying to create a new Arcade attribute expression in the content of a layer's pop-up window that does the following:

* Go through all elements contained in the layer "PARCELS"
* add up all the Shape_area of each element
* display the total

I tried a script like the one below, without success…

var table = FeatureSetByID($datastore,"PARCELS",[‘*’], true);

var total = 0;

for (var t in table) {

total = total + $feature["Shape__Area"]

}

return total;

If anyone can help me, I will accept with pleasure.

Thanks in advance.

Victor

jcarlson · Accepted Answer

For something as simple as this, you can use the built-in function Sum(), which can take a FeatureSet and field name as parameters.

Also, since the "SHAPE__Area" field is an attribute, you can specify that field alone and skip bringing in the geometry in the FeatureSetByName function to improve performance.

var fs = FeatureSetByName($datastore, "PARCELS", ['SHAPE__Area'], false)

return Sum(fs, 'SHAPE__Area')

That should return something like this:

JohannesLindner · Accepted Answer

You were on the right track (although there is an easier solution, as Josh pointed out).

Where you went wrong:

You used $feature in the for loop. $feature is a global variable describing the feature to which a popup/rule/label/etc applies, in your case the feature you click on. If your $feature isn't a polygon, the expression won't work. If your $feature is a polygon, you will get a wrong total (because you multiply the $feature's area instead of adding up the target areas).

This expression should work (although, again, Josh's answer is easier):

// Also, maybe you need to use FeatureSetByName here...
var table = FeatureSetByID($datastore,"PARCELS",[‘*’], true);
var total = 0;
for (var t in table) {
    total = total + t["Shape__Area"]
}
return total;