Specifies the length of time, in seconds, that must elapse between the time the app launches but before the launch is considered to be a new session. This timeout also applies when your application is sent to the background and reactivated.
The time that your app spends in the background is not included in the session length.
Specifies the length of time, in seconds, that must elapse between the time the app launches but before the launch is considered to be a new session. This timeout also applies when your application is sent to the background and reactivated.
The time that your app spends in the background is not included in the session length.
NOTICE: visits are still incremented for mobile apps but should not be used and instead launches should be used.
to add to above, if you are using data feed this documentation explains how to calculate a visit Calculating Metrics
Visits
Exclude all rows where exclude_hit > 0.
Exclude all rows with hit_source = 5,7,8,9. 5, 8, and 9 are summary rows uploaded using data sources. 7 represents transaction ID data source uploads that should not be included in visit and visitor counts. See Hit Source Lookup.
Combine post_visid_high, post_visid_low, visit_num, and visit_start_time_gmt*. Count unique number of combinations.
*In rare circumstances, internet irregularities, system irregularities, or the use of custom visitor IDs can result in duplicate visit_num values for the same visitor ID that are not the same visit. To avoid resulting issues, also include visit_start_time_gmt when counting visits.