Scale dependent layers visibility in LayerList

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07-15-2019 11:38 AM
AshleyPeters
Occasional Contributor II

I have two layers in my file that are scale dependent. How can I force the layerlist widget to only show that layer when the user is zoomed in to the point that the layer is visible and able to be turned on and off? I'm sure I'm missing something simple...

I'm using the Javascript 4.12 API.

Thanks in advance!

Ashley

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Egge-JanPollé1
MVP Regular Contributor

Hi Ashley Peters,

By default, if a layer is not visible in the map due to scale dependencies, it is grayed out in the LayerList. This is neat functionality, but apparently not what you want...

The trick to accomplish what you want is:

  • 'watch' the scale of you map with a watch handler
  • set the listMode of your layer(s) to hide or show accordingly.

See this code snippet:

// watch handler: the callback fires each time the scale of the view changes
var handle = view.watch('scale', function(newScale) {
    console.log("Scale: ", newScale);
    if (newScale > 500000) {
        dutchMunicipalitiesLayer.listMode = 'hide';
    } else {
        dutchMunicipalitiesLayer.listMode = 'show';
    }
});

I have published the fully working example here: ArcGIS JavaScript Tutorial - Scale dependent layers visibility in LayerList 

Hope this helps,

Egge-Jan

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2 Replies
Egge-JanPollé1
MVP Regular Contributor

Hi Ashley Peters,

By default, if a layer is not visible in the map due to scale dependencies, it is grayed out in the LayerList. This is neat functionality, but apparently not what you want...

The trick to accomplish what you want is:

  • 'watch' the scale of you map with a watch handler
  • set the listMode of your layer(s) to hide or show accordingly.

See this code snippet:

// watch handler: the callback fires each time the scale of the view changes
var handle = view.watch('scale', function(newScale) {
    console.log("Scale: ", newScale);
    if (newScale > 500000) {
        dutchMunicipalitiesLayer.listMode = 'hide';
    } else {
        dutchMunicipalitiesLayer.listMode = 'show';
    }
});

I have published the fully working example here: ArcGIS JavaScript Tutorial - Scale dependent layers visibility in LayerList 

Hope this helps,

Egge-Jan

AshleyPeters
Occasional Contributor II

Egge-Jan,

That worked beautifully! Thank you!

Ashley