Imagery Date/Time
Anchor date/time
On the prediction page, the
Show imagery for widget set
controls what date/time to "anchor" imagery to -- i.e. to
try to center the imagery range on. Clicking on the date/time
button will pop up a calendar/time dialog, and the date and time can
be selected. In that dialog, clicking a day selects that day, but
does not yet apply it; clicking a time selects that time and also
applies it (closing the dialog;
Esc also closes). Closing
the dialog makes that date/time the anchor for the
desired
imagery range (see contrast with
displayed range, below).
On the calendar, the current date is indicated with a small now
icon, and the event time (if defined) with a
small event time
icon.
The now button (or
pressing
n) sets "now" as the anchor date/time,
and will also automatically track it -- indicated by the button
turning blue (selected). (To pick the current date/time
but
not track it, select it via the calendar/time widget:
press the now button, then date/time button, then highlighted time.)
Selecting the now button also makes "now" the
(approximate)
start of the desired imagery time range for
forecast providers, and the
end time for satellite
providers. This is because forecasts are useful for the future,
while satellite imagery is available only for the past.
The event time button (or
pressing
e) sets event time as the anchor date/time, and
(roughly) centers the imagery range on it. It will also continue to
track event time, as indicated by the event time button turning blue
(selected). Event time is generally the default date/time set, if
it is defined. If the current map does not have an event time
defined, this button is disabled.
Duration
Duration selects how long to show imagery for. The
available options are determined by the provider and model selected;
different ones have different maximum durations.
Desired vs. displayed time range
Note that while
Show imagery for and
Duration
together select the
desired date/time range, the
actual
displayed range may differ, depending on the current
data available for the selected provider and model. If the selected
range is partially or wholly beyond available data, the displayed
range will be altered to fit. Looking at where the now/event time
(
/
) ticks are
can quickly indicate whether the displayed range matches the desired
range. (See details on the
Imagery
Animation help page.)