sl.trackingshot: Create Trackingshot Movie

In helgegoessling/spheRlab: Spherical Geometry, Analysis, and Plotting of Geoscientific Data on Arbitrary Grids

Create Trackingshot Movie

Description

Creates a specified number of temporary images and concatenates them to a video. SEE NOTE 1) BELOW FOR A WORKAROUND FOR AN EXISTING ISSUE.

Usage

sl.trackingshot(way, num, lon, lat, elem, 
  fps = 25L, time = NA, ffmpeg = Sys.which("ffmpeg"), 
  col.background = "white", col.fill = "colbar", col.border = "colbar", 
  colbar = sl.colbar.redgreyblue_256, colbar.breaks = NA, 
  border.lwd = 0.01, border.lty = 1, out.path = getwd(), file.name = "sl.trackingshot.mp4", 
  width = 1080, threads = 1, delete.images = TRUE, verbose = TRUE)

Arguments

way	list of class sl.way like the one returned by sl.trackingshot.way
num, lon, lat, elem	Corresponding argument to sl.plot.field.elem
fps	scalar representing the video's frames per second. Must be greater than 0.
time	Scalar or NA. If NA the way's times will be used, otherwise it will be stretched to time's size.
ffmpeg	String. Path to ffmpeg executable.
col.background	Image background
col.fill	Fill color for polygons
col.border	Polygon border color
colbar	List containing color codes.
colbar.breaks
border.lwd	Border line width
border.lty	Border line type
out.path	Output path for the video file (and the folder with the temporary images)
file.name	File name for the video file
width	Base width for all images in pixels
threads	Thread count to use for creating images
delete.images	Logical value indicating if produced images should be deleted after the video is created
verbose	Logical value indicating whether additional info is printed

Note

1) It appears that the function fails if it's immediately executed with multiple threads. This can be circumvented by starting the function with a single thread, aborting it (if more threads are desired), and re-running it with multiple threads.

2) This initial implementation of the function is designed to make movies based on one specific plotting function, namely sl.plot.field.elem. For the future it would be nice to make this tool more general. For example, the trackingshot function could take a function containing arbitrary plot calls as an argument. The user could then define such a function quite generally, e.g., adding coastlines, points, or whatsoever. Ideally, it should also be possible to use data with a time dimension, so that not only the view is changing but at the same time the displayed field advances in time.

Author(s)

Lukas Müller, slightly modified by Helge Goessling

Examples

## Not run: 
### read mesh
mesh = sl.grid.readFESOM(griddir="somedir",rot=TRUE,rot.invert=TRUE,rot.abg=c(50,15,-90))
# a sample mesh can be obtained from GitHub, e.g., using 'svn checkout' from the command line:
# > svn checkout https://github.com/FESOM/FESOM-data/trunk/pi-grid ~/pi-grid

### read corresponding data
require(ncdf4)
dat.file = nc_open(filename="somecorrespondingdata.nc")
dat = ncvar_get(nc=dat.file)
nc_close(nc=dat.file)

### define projection and way
projection = "polar"
p1 = sl.trackingshot.waypoint(projection = projection, time = 1, polar.lonlatrot = c(0,90,0), polar.latbound = 0)
p2 = sl.trackingshot.waypoint(projection = projection, time = 1, polar.lonlatrot = c(15,50,0), polar.latbound = 20)
p3 = sl.trackingshot.waypoint(projection = projection, time = 1, polar.lonlatrot = c(-60,-30,0), polar.latbound = 60)
p4 = sl.trackingshot.waypoint(projection = projection, time = 1, polar.lonlatrot = c(100,40,0), polar.latbound = 20)
p5 = p1
p5$time = 0
points = sl.trackingshot.waypoints(projection = projection, p1, p2, p3, p4, p5)
way = sl.trackingshot.way(waypoints = points, times = c(5,5,5,5))

### make video
sl.trackingshot(way = way, num = dat, lon = mesh$lon, lat=mesh$lat, elem=mesh$elem, fps = 30L, width = 1920, threads = 3, file.name = paste0("~/video_", projection, ".mp4"))

## End(Not run)

helgegoessling/spheRlab documentation built on April 8, 2024, 8:34 a.m.