LET @name = @name ENDPOINTS
LET @name = @name LEFT ENDPOINTS
LET @name = @name RIGHT ENDPOINTS
The EXTRACT command is used to extract one or both endpoints of each interval
from an input schedule. The resulting schedule contains only intervals of
length zero.
A graphical description of the EXTRACT command is shown below.
(LEFT ENDPOINTS)
Input schedule : --- --------- --------- -
Output schedule : - - - -
(RIGHT ENDPOINTS)
Input schedule : --- --------- --------- -
Output schedule : - - - -
(ENDPOINTS)
Input schedule : --- --------- --------- -
Output schedule : - - - - - - -
The ENDPOINTS command is most often used to generate a schedule containing
only the beginning or end of an event such as an occultation or eclipse. The
resulting zero-length intervals are often expanded immediately afterward. In
the following example, the ENDPOINTS and EXPAND commands are used to generate
intervals containing the 10 minutes after and before the beginning and end of
a series of eclipses.
FIND ECL ECLIPSE OF SAT BY PLN FROM EARTH STEP SIZE LENGTH; LET ECL_BEGIN = ECL LEFT ENDPOINTS; LET ECL_END = ECL RIGHT ENDPOINTS; LET ECL_BEGIN = ECL_BEGIN EXPANDED RIGHT 10 MINUTES; LET ECL_END = ECL_END EXPANDED LEFT 10 MINUTES;