Georeferencing a raster automatically

Auto registration allows you to automatically georeference your raster dataset to a referenced raster dataset. The automated links are based on spectral signatures, so it is meant for aerial and satellite imagery, which is similar in nature. The auto registration does not work well with scanned maps or historical data.

To use it, you must place the nongeoreferenced raster dataset in the generally correct geographic location along with a referenced raster that is in a known coordinate system. The Fit To Display, Shift, and Rescale tools help you place the raster dataset in the approximate geographic location. When you click the Auto Registration button, the system attempts to create links from your unreferenced raster dataset to your referenced raster dataset. If accurate links cannot be created, you may need to adjust the source raster dataset to better overlap the referenced raster dataset.

Tip:

To achieve a higher success rate in autoregistration, the two images need to be as similar as possible: geographic location, time and season, image orientation, image scale, and band combination.

Steps:

1. In ArcMap, add the target raster that resides in map coordinates, then add the raster dataset you want to georeference.

   Adding the raster data with the map coordinate system first is a good workflow so that you do not need to set the data frame coordinate system.

2. To display the Georeferencing toolbar, click the Customize menu and click Toolbars > Georeferencing.
3. Make sure that the layer you are georeferencing is selected in the Georeferencing layer drop-down box.
4. Zoom in to the approximate location where your raster dataset should be located.
5. Use Fit To Display to move the raster dataset into the display.
6. Use the Shift and Rescale tools to more accurately place the raster.
7. Click the Auto Registration button .
8. In the Link Table, evaluate the links that were created.
   1. Delete any links that do not appear to be accurate.
   2. Create more links if necessary.
9. Click the Georeferencing drop-down menu and click either Update Georeferencing or Rectify. Updating the georeferencing saves the transformation information with the raster and its auxiliary files. Rectifying creates a new file with the georeferencing information.

Note:

You can permanently transform your raster dataset after georeferencing by using the Rectify command (click the Georeferencing drop-down menu and click Rectify), the Warp tool, or the Warp From File tool.

Note:

Updating a raster layer, an image service, or a mosaic layer only updates the layer within your map document; it does not save the georeferencing information back to the source.