topic Re: Access Layer Properties for WebMap Layers in ArcGIS JavaScript Maps SDK Questions

Access Layer Properties for WebMap Layers

StefanFreelan — Sat, 10 Sep 2022 22:33:02 GMT

Hi All,

I've got a working webmap (JS 4.24), using an AGOL web map but I can't figure out how to access the individual layers contained in the webmap. I just want to be able to reference a specific layer so I can do things like toggle it's visibility.

I've tried a couple of methods (see below), but if they are working I haven't been able to find a way to then reference the layer (where do I put the visible: true, statement? Or the listMode: 'hide' statement?

Obviously I'm fairly new to JavaScript...

Is there a better way to reference a layer in a webmap?

Having referenced it, how do I set it's properties?

Any advice or suggestions appreciated,

thanks,

~stefan

Stuff I've tried:

const webmap = new WebMap({
portalItem: {
id: "9c161033f604436193805a7484feab3d" // Web Map for JavaScript
}

});

const view = new MapView({
container: "viewDiv",
map: webmap,
});

// get layers when the view is initialized
webmap.when(() => {
// layer 0
const layer0 = webmap.layers.items[0];
});

// OR Find a layer by ID...
const layer1 = webmap.findLayerById("958f6534812a4407925a2a18a640b841");

Re: Access Layer Properties for WebMap Layers

UndralBatsukh — Mon, 12 Sep 2022 17:05:15 GMT

Hi there,

You can loop through all operational layers in your web map after all resources are laded and find the layer you need. The following code should get you started:

webmap.loadAll().then(()=>{ // loop through all operational layers in your webmap webmap.layers.forEach((layer)=>{ console.log("layer.id", layer.id, layer); // check your layer here }); });

This sample also shows how to get a layer at the specified index. https://developers.arcgis.com/javascript/latest/sample-code/sandbox/?sample=featureeffect-drop-shadow

Re: Access Layer Properties for WebMap Layers

StefanFree — Thu, 15 Sep 2022 03:37:26 GMT

Thanks UndralBatsukh, I'll see if I can get this to work.

Re: Access Layer Properties for WebMap Layers

Jeff-Reinhart — Tue, 30 Jul 2024 18:45:57 GMT

Thanks! This helped with a different timing issue I was having where the map.allLayers.items[0].renderer.uniqueValueInfos was coming up undefined.