I've made a mosaic dataset of some thermal imagery. There are three overlapping images, seen here:

enter image description here

As you can see, there is a discontinuity (jagged edge) between the two images on the right, and a slight offset in the southern fenceline. I want to tackle this using the Blend function in ArcMap 10 to "average out" these small differences and create a seamless mosaic.

The online help tells me there should be a Blend Width option to control the area over which the rasters are blended... However, this is all I see:

enter image description here

Does anyone have any experience with this? I've looked in all the other tabs/online and can't find anywhere to define the blend with. I feel like I must be missing something obvious... I am using ArcMap 10.0 with an ArcInfo license on Windows 7.

Any help would be appreciated- thanks!


Based on the help you linked to, it doesn't seem like that is setting that can be changed. I know it's semantics, but you'll notice that it says:

Blend Width—Defines the distance in pixels (at the display scale) used by the Blend mosaic operator.

For the other options, it says "Allows you to define" or "You choose".

However, if seamlines are present, it would appear that you can define the blend width:

If seamlines are present, a blending width and type can be defined for each seamline in the seamline table, thereby overriding this value.

This ESRI article would also support that the blend width is dynamic, and changes based on your zoom level.

The unit of measurement for the blending of mosaic datasets is in pixels not map units. The request size for the width of the blending is based on pixels in the view. Because the number of pixels in a view changes (overviews, pyramids) when zooming in and out, this may not be constant.

Lastly, the Build Seamlines tool has a parameter under the Advanced options to set the blend width.

  • Thanks Paul- I will try building some seamlines and report back. – Sam Zipper Jul 23 '13 at 17:09

The solution I came up with is as follows:

-Create Raster Dataset

-Add the images I want to mosaic to that dataset

-Select 'Blend' as the mosaic operator

(follow this YouTube video for more step-by-step, all you have to do differently is change the Mosaic Operator).

Arc will automatically blend over the entire overlapping width. It's not perfect (because you don't have control over the blend width), but the results look pretty good:

enter image description here

I tried setting up seamlines, as suggested above, but it turned out to be too much of a hassle to figure out how to place them in the right place. For someone more experienced, that may be a better option.

Hope this helps!

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