Georeference a raster to a referenced layer

You can georeference a raster to either another raster layer or a feature class. When georeferencing, look for well-defined objects in your images, such as road intersections or land features. These objects should be on the ground and should not be elevated features. This way, you can be certain that you are referencing the same location in both the raster and aligned layers.

Note:

The raster layer you are georeferencing must either be in the same coordinate system as the map frame or have no spatial reference defined.

Note:

Saving the ArcGIS Pro project does not save the current state of a georeferencing session. Export your control points before you close the project.

1. In ArcGIS Pro, add the reference layers residing in map coordinates. These layers can be a raster, a feature class, or a basemap.
2. Add the raster dataset you want to georeference.

   Adding the data with the map coordinate system first is a good practice so you do not need to set the map frame coordinate system. It also places the raster you are georeferencing above the reference layers.

3. In the Contents pane, right-click a target layer (the dataset in the correct location) and click Zoom to Layer.
4. In the Contents pane, click the source raster layer you want to georeference.
5. Click the Imagery tab and click Georeference to open the Georeference tab.

   The tools on the Georeference tab are divided into several groups to help you use the correct tools in the different phases of your georeferencing session.

6. In the Prepare group, click Set SRS .

   If your raster dataset already has a spatial reference, it is automatically used as the coordinate system for the map and the georeferencing session. If your raster dataset does not have a spatial reference, the Map Properties dialog box appears, and you can choose the coordinate system for the georeferencing session. The default spatial reference is the current coordinate system of the map.

7. Use the navigation tool to zoom and pan to the location of your source raster.
   1. Optionally, click Locate to zoom in to a city or address.
8. Click Fit To Display .

   The raster layer you are georeferencing is placed with the current map display.

9. Optionally, use Move , Scale , and Rotate to place the raster as needed.
10. In the Contents pane, turn off the visibility of any layer that you do not want to use as a reference dataset. This includes the basemap layer, unless it is the World Imagery layer.
11. In the Adjust group, click the Add Control Points tool to create control points.

    To add a control point, first click a location on the raster you are georeferencing (the source layer); then click the same location on the target layer on the map (the reference data).

    If you are using another raster as your reference layer, press the L key to turn the transparency of your source raster on or off.

12. On the Transforms drop-down menu , choose the transformation you want to use.

    Zero-order polynomial	Minimum of one control point required
    First-order polynomial	Minimum of three control points required
    Adjust	Minimum of three control points required
    Projective transformation	Minimum of four control points required
    Second-order polynomial	Minimum of six control points required
    Third-order polynomial	Minimum of ten control points required
    Spline transformation	Minimum of ten control points required

13. In the Review group, click the Control Point Table button to evaluate the residual error for each control point.

    Press the L key to switch the transparency of your source raster on and off.

14. Delete any unwanted control points using the Control Point table. Alternatively, edit the inaccurate points by selecting them and moving the vertices.
15. When you're satisfied with the current alignment, stop entering control points.
16. In the Save group, choose how you want to save your georeferencing information.

    Save	Save the georeferencing information with the raster and its auxiliary files.
    Save as New	Create a raster file with the georeferencing information.
    Export Control Points	Save the control points in a text file.

You can now use your georeferenced raster dataset in your GIS projects.

For more georeferencing workflows, see Georeference historical imagery in ArcGIS Pro.