Thursday, January 24, 2013

SST - the 3D movie

Well, maybe not quite 3D, but the movie is painted on a globe that you can rotate while it is running.

This is a follow-up to my post yesterday pointing to a new page with NOAA/NCDC SST data displayed on a WebGL globe that you can rotate and zoom.

I have added a movie facility show you can see the dynamics of processes like ENSO. The process works like this. First you select your start date and resolution, as if you were plotting that date. But instead of New Plot, go to the bottom, next to the new Seq button and enter the Step (interval in days) and Number (of frames in the movie).

Then press Seq. This will download the data for the frames. At 1° resolution, this will show as a passable movie, but at 1/4° it will be painfully slow. But let it run. You'll see a pink window just above counting the frames - it will revert to pale green when finished.

Now the payoff - next to the Cyc button you can enter the cycle time for the real movie. For resolution 1/4° you may find that times less than 1 sec will lead to skipping frames; coarser resolutions should do several frames per second (if you really want). Then press Cyc to run the same sequence that you just downloaded, but at the faster speed.

Long sequences at high res will be a load on memory - I estimate about 3-4 Mb per frame. I've been juggling memory vs speed - I can run very fast, but needing 10 Mb per frame.

You can rotate or zoom while the movie is running. You can rerun (Cyc) as you wish. You can go on to do other plots or make more movies, but then you can't rerun the one you had been watching.

I've found that it works as described in Firefox. In Chrome it works, but doesn't show the frames while loading (following Seq) and the red colors don't show to indicate. The movie is OK though. I'm investigating (probably tomorrow).

Where the exact day in sequence is missing, the movie takes the nearest,

It's great for dynamic processes such as ENSO. 1998 is very impressive, even with monthly steps. I'll load more data for this period overnight. I'd recommend starting with low resolution and sequences of 10 frames or so.


  1. Completely OT, but there is a blog storm headed your way. The editors of APC have accepted Makarieva et al on the grounds that there have been lots of blog comments:)

    1. Eli,
      Yes, it's in line with the logic of these journals. When she was berating them for rejecting her last paper, they wearily said - so? Your paper's there for everyone to read, and has had far more attention than most accepted papers.

      It's similar to the ESD editor's acceptance of the Beenstock paper:
      "I expect this paper will be thoroughly discussed and maybe criticized a bit. But I must say all reviewer’s comments were excellent and such challenging work is needed in our field of work. I’m therefore pleased to accept the manuscript in its final form."

      The excellent comments said it was crap. But hey - it's been peer reviewed and should get a lot of hits.

      "lots of blog comments"
      Ah well, I guess I did my bit :(