WCPS-Tutorial / Trimming: how to do interval subsetting
Trimming a coverage extracts a cutout along the axis indicated, specified by a lower and upper bound on this axis. Obviously, as we talk about subsetting, the new interval limits must lie inside the original coverage's domain.
mowglie is a 3-D RGB cube with axes x, y, and time.
Actually, as you may realize, this is a downscaled excerpt from Walt Disney's Jungle
Book where the image frames have been stacked along the time axis.
To get an impression of this time series stack see the image below, or download this coverage as an mpeg stream.
in WCPS Abstract Syntax this is expressed using the previously introduced request:
for m in ( mowglie ) return encode( m, "mpeg" )
On this cube, we perform subsetting to get a cutout along x axis between 90 and 110 and along y axis between 60 and 90.
for m in ( mowglie ) return encode( trim( m, trim( m, x(90:100) ), y(60:90) ), "mpeg" )
The first frame of this video cutout is displayed below:
See manual: trimExpr