# GeoRef Layer

This layer allows one to use any image as a map. You will need to tell it how to align the map to a position in the world and the scale of map.

When a new image is selected the values from a World File will automatically be tried to be found. (subject to the setting in prefs_external)

&appname; does not currently support skew values and since World Files do not contain what coordinate system the coordinate values are in - &appname; assumes they are in UTM.

If you do not know the scale of the map but know the coordinates of both upper left and lower right coordinates, you can enter these coordinates (Lat/Lon only) and then use the Calculate MPP values from coordinates button.

The map once loaded can be repositioned via georef_tools, which may be easier than trying to edit the raw property values.

## Layer Properties

Configurable properties:

- The map image file.

- X + Y Scales in metres per pixel.

- Coordinates of the upper left corner of the map (either UTM or Lat/Lon value).

- Alpha. Control the Alpha value for transparency effects using a value between 0 and 255 with the default being 255 for a fully solid image, whereas 0 is transparent.

## Layer Operations

### Zoom to Fit Map

Automatically set a zoom level to see the entire map coverage.

### Goto Map Center

Center the viewport on this map.

### Export to World File

Opens a file save dialog to save the scale and position information as a World File.