# Overlays and layers

> Bring shapefiles, GeoJSON, images, PDFs, historical maps and WMS layers onto the map.

On **Pro**, you can bring extra map data onto the base map - your own files,
historical mapping, and live WMS services. Each is a layer you can show, hide and
fade.

<Callout type="note" title="A Pro feature">
  Overlays and layers are **Pro** features; adding overlays also needs a role that
  can edit the map.
</Callout>

## Overlays

The **Overlays** layer drapes your own data over the map:

- **Vector** - upload **GeoJSON** or **shapefile** data.
- **Raster** - upload an **image** or **PDF** to position over the map, with
  **crop**, **rotate** and transform tools.

Each overlay has its own **opacity**, **visibility** toggle and style.

Overlays are scoped to **this project** by default. From the overlay's options
menu you can make one a **configuration overlay** so it shows on every project
that uses the same configuration - these are marked with a globe on the overlay's
row.

### Positioning a raster overlay

**Unlock** a raster overlay to reveal its handles, then:

- **Move** - drag the middle of the overlay.
- **Resize** - drag a **corner** to scale it (aspect ratio is kept); hold
  **Shift** to stretch it freely. Drag an **edge** to stretch one side.
- **Rotate** - drag the rotate handle; hold **Shift** to snap to 15 degrees.

**Undo** and **redo** your changes with **Ctrl+Z** and **Ctrl+Shift+Z**, or the
undo/redo buttons on the overlay's row.

### Align with two points

For an accurate plan or drawing, you can place it by matching **two known
points** rather than dragging by eye. From the overlay's options menu (the
**...** button) choose **Align with 2 points**, then:

<Steps>
  <Step title="Pick a feature on the image">
    Click something you can identify on the overlay - a building corner, a survey
    marker, a grid intersection.
  </Step>
  <Step title="Place it on the map">
    Click where that feature actually sits on the base map.
  </Step>
  <Step title="Do it again for a second feature">
    Repeat for a second point. On the last click the overlay moves, scales and
    rotates so both features land on their targets.
  </Step>
</Steps>

The image keeps its shape (it is not skewed), so this works best with accurate,
to-scale drawings. Press **Esc** or **Cancel** to stop; **Ctrl+Z** undoes it.

## Historical maps

The **Historical Maps** layer adds historical and geological base mapping beneath
your data, with opacity and visibility controls.

## WMS

The **WMS** layer adds external **WMS** services as map layers, with opacity and
**click-to-query** for feature details.