Mosaic Dataset has white area outside the imagery area

[Stephanie_Shaw]

ArcGIS Pro V 3.5.4; Pro + License

My goal is to create a mosaic dataset in ArcGIS Pro to be published as a WMTS (Web Map Tile Service) on AGOL. Defaults were used unless otherwise stated below.

Workflow:

Prep Step (Delete any *.OVR files from the folder where the Geo Tiffs are stored) 

I created a new project called "Imagery" and used the default as my gdb

I created a Mosaic Dataset (natural color, 8 bit unsigned)

I added raster (Processing template :stretch, raster type: raster dataset, input data: folder)

I built footprints (radiometry, min =1 max =254, unchecked skip overviews and kept update boundaries unchecked)

I built seamlines (comp method= edge detection, checked update existing seamlines, sort method northwest,  sort ascending checked)

Define Overviews (force overview tiles checked, number of levels = -1, resampling method nearest neighbor, quality= jpg 80

Build Overviews (unchecked define missing overview files)

From Here I want to publish it as a tile service but I need the white area problem fixed first.

* since my footprints were 1-254 this should drop out 0 for white, 255 for black and 256 for no value, right?

Everything I read said not to clip the raster mosaic dataset but to use building footprints tool but I have and I can't get rid of the band. It appears to be the portion of the *.tiff that has been removed by the supplier of the aerial imagery. I am currently running a clip raster (my mosaic data set as the input raster and a 200 ft buffer around my county boundary as the output extent. But I would love to know how to update my workflow to prevent this from being created so I don't have to clip it. I had the same problem with my imagery last year but went ahead and published it out as a WMTS anyway. I really want it clean this year, as I need it to display with neighboring imagery and this white area creates a problem. I have also included a link to last years WMTS, that has the same problem. (https://tiles.arcgis.com/tiles/G4bYaaas92zuKaUR/arcgis/rest/services/BentWashImg2024Pack/MapServer)

[RTPL_AU]

Hi Stephanie

The easiest by far for future data is to set a requirement that your supplier delivers a 4band image with transparency set for any no-data areas. 
Most good ones do by default, unless an old contract specifically told them not to 🤣

If your current Tiffs have compression then the 'white' band will likely have artefacts so when you set a single value as no-data you may still be left with blotches of Lexington (a shade of white. renovating, sorry).

Editing footprints being preferred is valid - but can be quite fiddly for complex areas. 
Create a few boundaries/extents that you can use to either clip imagery dynamically or to clip the mosaic footprints against. 
This means you'll have consistency across datasets.

This is such an AI task  "Computer, delete the white border, then zoom in and enhance".....   well, maybe not the enhance bit.