> For the complete documentation index, see [llms.txt](https://docs.jmapcloud.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.jmapcloud.io/en/jmap-cloud-portal/user-guide-for-jmap-cloud-portal/configuring-project-data/organizing-project-layers/duplicating-or-referencing-a-layer.md).

# Duplicating or Referencing a Layer

You can add a layer to the project by duplicating or referencing an existing layer:

* You can duplicate a layer from the same project.
* You can duplicate or reference a layer from another project.

{% hint style="warning" %}
You cannot duplicate or reference a layer that is itself referenced from another project.
{% endhint %}

When you click <img src="/files/xVYYH7h5QbILQhfSGWWK" alt="" data-size="line"> in the **Layers** panel, the **Duplicate and Reference Layers** interface opens.

The interface displays cards for each project (including the project currently open in Studio) that you have access to. The expanded card displays the available layers.

A search bar allows you to filter layers by name.

Select the layers you want and click **Reference** or **Duplicate**.

The available functions depend on the selected layers. If you select layers from the project currently open in Studio, only the **Duplicate** function is enabled. If you select layers from other projects, both functions are enabled.

## Duplicating a Layer

When you duplicate a layer, the new layer is created in the project you are currently editing.

The new layer is a copy of the original layer (styles, labels, tooltips, etc.).

The two layers - the original and the duplicate - are independent of each other. They use the same data source.

## Referencing a Layer

When you reference a layer, the new layer is created in the project you are currently editing.

All properties of the new layer (styles, labels, tooltips, etc.) are identical to those of the original layer. It is not a copy.

As a result of referencing, the new layer points to the original layer.

You cannot change the properties of the new layer. You can display it as-is in the project.

You can change:

* The layer name
* Its description
* Its initial visibility
* The initial zoom level
* Whether it is listed in Studio and in JMap NG

The referenced layer is identified as such in the project.