I ran a data extract in Data Warehouse to get daily/monthly data by channel drilling down to tracking code. When comparing the visits in Adobe Analytics 'Channel Report' to the data in Data Warehouse, the numbers in data warehouse are almost half of what is showing on the 'Channel Report'. I was thinking that Data Warehouse may be automatically classifying 'visits' as 'unique visits'? Could someone validate?
I thought the same. I checked the reports you ran, and I can see them containing Visits. I can also see two of them containing both metrics. Are you able to confirm if the Visits - All Visitors matches.