Creating a mosaic dataset containing rasters from multiple dates

[KeonMonroe]

Hello - I am trying to follow this workflow outline from this ESRI page on creating a mosaic dataset containing rasters from multiple dates. Essentially, it recommends creating mosaic datasets for each year and then adding those to the master mosaic dataset which will contain imagery from all years.

I'm confused about the step to "Add a service as the overview" (nearly halfway down the page). It seems be recommending that I add an existing image service to work as an overview layer for the master mosaic dataset. However if this my first time setting up the imagery and mosaic datasets, wouldn't I first need to publish out a tile layer or something similar so I could achieve this? 

To elaborate, I am attempting to create a mosaic dataset with imagery from 2018 and 2020 (and then I have a master mosaic dataset containing the mosaic datasets for each year, as the worflow suggests). If I haven't published any image services yet, why is it recommended to add a service as the overview instead of updating overviews when creating the master mosaic dataset?  It seems like it would make more sense to publish each of the years as an image service, then add those layers to be used as overviews. 

Am I missing something here? 

Any help is appreciated. Thank you.

[CodyBenkelman · Accepted solution]

First, note you're looking at Help for ArcMap 10.3.  That is very old; are you using 10.3?  

Second, I'd recommend you look at this resource which is newer and should have very similar advice (and should be applicable to 10.x although most of us now use ArcGIS Pro.)

Introduction—Managing Preprocessed Orthophotos_Overview | ArcGIS 

Third, re: the specific question, that doc was probably not quite clear enough but the intent was "you MAY want to use an image service from ArcGIS Online for low resolution views INSTEAD of creating your own overviews..." but it is optional.  You can create overviews from your imagery.   

I've advised switching to a different data source for low res views in the past for several reasons:

• air photos often do not look very good when you create overviews and zoom way out... small scale satellite images typically just look better
• if you have 2+ years, do you really need overviews of each year?  if only one year is needed, which do you use? 
• Does your imagery have much value when viewing at ~100 m/pixel or lower resolution?  --> my feeling is "the overview is needed so the user can see context - mountains, rivers, etc. and navigate to the proper area - but the content of your specific imagery is (often) not highly relevant until you zoom into higher resolution..."

If you disagree with the judgment that "your unique content is not relevant at 100m" then by all means ignore this option.  This is just an alternative to provide imagery that is appropriate for low resolution views, but you can ignore the "use a service" option and use your own imagery to generate overviews

[PeterBecker]

There are cases where you may be creating imagery from collections of data and there are no overviews for that data. In that case when zooming out users will not see anything. This can be confusing for users. One recommended option is to ensure that overviews exist for each of the different dates. If combining into a single master mosaic dataset it is important to ensure that date attribute is appropriately set. An alternative creating overviews is to use some other service data source as an overview. One can for example use ArcGIS World Imagery as an overview which will then be displayed at small scales. If you create a layer it you can then add that layer as a raster in the mosaic dataset and set the attributes so that it will be displayed at the appropriate scale or dates.