00:06In ArcGIS 10.1, we've added an option to automatically georeference your images.

00:12You can access this option from the georeferencing toolbar.

00:16I'm just going to open it from the Customize menu > Toolbars > Georeferencing.

00:25Now I'm going to add my image that is referenced to the display.

00:30So here I have a QuickBird scene.

00:32I can take a look at its Properties.

00:34It's QuickBird.

00:35It's Standard2A processing, and it was taken in 2005.

00:39I'm going to add its Multispectral product to the window.

00:43Then I'm going to zoom to an area...

00:46...where I know that my ungeoreferenced image basically lines up.

00:56Next, I'm going to add in my unreferenced image.

01:01And you can see that the georeferencing is unknown.

01:07So there's a few things I can do.

01:09First, I'm going to make sure that it's selected in the Georeferencing toolbar.

01:15Then, I'm going to fit the image to the display.

01:20And this brings it in.

01:25There are other things you can do.

01:26In this case, my image is oriented approximately the same as the other image.

01:31But I can do things like scale, shift and rotate the image into place.

01:36I can also choose to rotate it, a prescribed amount, or to flip it, a certain way.

01:45In this case, I'm just going to click the auto-georeferencing button and let it work.

01:49This process finds matching control points between the two images...

01:53...based on their spectral characteristics.

01:55Therefore, to get the best results, it's recommended that the two images...

02:00...have similar spectral characteristics in that they be as similar as possible.

02:04For example, two natural color images like we have here of similar pixel sizes.

02:10You won't get good results if you use a low-resolution image as the base...

02:14...to auto-register a high-resolution image.

02:17You also won't get good results if you try and auto-register a black-and-white image...

02:20...to a color image.

02:22It's also best to center the display in the approximate location...

02:26...of the ungeoreferenced image as I have done here.

02:30So once the process is complete, you can examine the control points visually, or...

02:34...by looking at them in the display or you can open the links table.

02:40So here you can see information like the RMS Error.

02:50You can also go in and look at the link.

02:55You can remove it or add in new ones if you want to as well.

03:03So the next thing I'll do is I can simply choose to update the georeferencing...

03:09...which will update the transformation stored on disc...

03:12...or I can choose to rectify it, which will write out a new georeferenced image.

03:16In my case, I just want to update...

03:18...the information that is stored on disk and not create any extra image files.

03:24And now I can continue to work with my image and it into...

03:27...other ArcMap sessions as a georeferenced image.

03:31Next, I'm going to move onto another example.

03:34Here I have another image that's basically in the right location, but it's not quite right.

03:41This is quite typical of some satellite imagery...

03:44...that isn't processed as accurately as other imagery.

03:50So here you can see that my roads...

03:53...in my vector file don't quite line up with my roads in my image.

03:58And if I want to make sure that it's my image that's off, and not my vectors that are off.

04:04What I'm going to do is I'm going to bring in a basemap...

04:07...that I can get to from ArcMap that comes from ArcGIS online.

04:10I'm going to open the Imagery Basemap because I'm going to ultimately use it...

04:15...to fix the georeferencing of this image that's being displayed.

04:21So, because it's a basemap, it automatically gets pushed to the bottom...

04:24...of the table of contents and underneath everything.

04:26So I've turned off my Multispectral scene.

04:30And you can see that my roads line up perfectly with this Basemap image.

04:39So next, I'm just going to zoom back out and turn on my Multispectral scene...

04:44...and I'm going to use my Basemap to correct the image that I displayed.

04:48You can see that nothing is selected in the Georeferencing toolbar.

04:52And this is because the projection isn't appropriate for georeferencing.

04:58So I'm just going to change the Properties of my Data Frame.

05:03I'm going to choose one of the Layers that are already in the map and click OK.

05:08And, yes, I want to reproject everything.

05:13So next, I'm just going to make sure that image I want is selected, which it is.

05:18I don't need to reorient this one; I just need to click auto-georeferencing.

05:24So, just as before, the statistics of the imagery basemap...

05:29...and the statistics of my image are going to be calculated...

05:34...then the two images will be compared to find the matching control points.

05:42So now I can zoom back in...

05:47...and I can see that my vectors do line up much better than they did before.

05:56And just as before I can choose to either update...

06:02...or rectify the image by writing in a new file.