Starting in GBrowse version 2.13, administrators have the option of configuring a summary view (feature density) for tracks when zoomed out too far to effectively show individual features, and starting with the 0.30 release of Bio::DB::Das::Chado this functionality is supported for browsing Chado databases with GBrowse.
To support the summary view,
Chado needs an
additional table that the Chado GBrowse
adaptor will use to calculate the
summary view. To create this table (gff_interval_stats) and populate it
with data, the
Bio::DB::Das::Chado
distribution comes with a perl script,
gmod_create_summary_statistics.pl. Executing this script, optionally
with a --dbprofile flag to indicate the database to work on, will
create the table if it doesn’t exist, as well as a few stored procedures
for populating the table, and then execute the stored procedure. This
script can also be used in a
cron job to periodically recreate the
data in the summary statistics data when the data in the table becomes
stale due to added data.
To turn on summaries, add this line to your data source’s conf file in the main section:
show summary = 100000
which will make all tracks go to the summary view when the region shown is greater than 100000. To turn summaries off for a given track, add
show summary = 0
to the track configuration.