Mosaic Dataset build footprint based on alpha band

Question

Hi Peoples,

I have a number of ECW rasters that contain an alpha band that acts as a transparency mask.

I would like to calculate footprints for the rasters.  I can't see how to specify to use just the value of the alpha band to achieve this.  Anyone done this?

https://pro.arcgis.com/en/pro-app/latest/help/data/imagery/raster-display-ribbon.htm

Cheers,

Mark

GordonSumerling · Accepted Answer

Hello Mark,

Yes this can be achieved. I have utilised raster functions to do this. Usually the alpha channel is 0 & 255.

So what you do is as follows:

* Use the raster function to Extract the Alphas channel from the image (Extract Bands)
* This will give you a single band image of 0 & 255
* Then use the GP tool Raster to Polygon.
* This will give you a vector layer of the image boundary and the image content.
* You can then filter the vector layer by either of the values.

Hopefully this is what you are after. You can even use this shape to replace the footprints in a Mosaic dataset

Cheers

Gordon