A Visualizer for Directional Buoy Data

The Java applet above lets us browse several days of recent data from the Point Reyes wave riding buoy. This data shows the wave energy in 9 frequency bands and the direction that the energy in each band is coming from. Run your mouse over the spectrum or time and date display on the bottom to see the direction and height for each time.

This application is designed for use by wave watching surfers (me in particular) and it will be added to my surfers weather site soon. Shorter period waves on the blue end of of the scale are created by local winds and tend to junk up the surf. Longer period swells on the red end make the most surfable waves. These are mostly produced in large and sometimes distant storms. Some surfable summer waves for us in California come from as far away as New Zealand. Winter waves often come out of the Gulf of Alaska. The direction graph points to the source of the components and surf breaks respond differently to swell mixes and directions. Having a few days history lets us spot trends and we can look back after a good or bad session to try to read the signs.

The bands run from a wave period of 22 seconds and greater colored dark red to one of 4-6 seconds colored dark blue. The nine bands are 22+ seconds period dark red, 18-22 red, 16-18 orange, 14-16 mustard, 12-14 yellow, 10-12 green, 8-10 dark green, 6-8 light blue and 4-6 seconds dark blue.

This page has been a sketch pad and test bed for ideas I've been working on. There have been many changes here over the last few weeks and I'm still tweaking.

I'm interested in your impressions and suggestions. Email your comments to surfcast@pwizardry.com


-- Frank Cox


--  By 12/8/2000 the necessary elements for a basic buoy browser 
were included. This matches my original estimate of a two week basic 
development time. Not too bad considering this is my first Java app
and I only worked on it part time. There was (and is) still a list 
of open issues but they are relatively minor and I've been working 
on them slowly.

-- The bigger open issues include:

   o Both direction and height displays need improved size scaling.
     (I did some work on scaling on 12/21).
   o The data collection system will be more robust.

-- These features will be added in the future.

   o The ability to browse other CDIP and also NOAA buoys. 
   o Missing data will be dealt with in some sensible way.

--  The data gathering code now runs twice an hour on my data 
collection server (an old IBM 701 "Butterfly" laptop, 486/2 50MHz). 
There seems to be an hour or more lag before buoy data makes it to 
the CDIP servers so this display will be at least that far behind.

--  The swell component height and direction display has been
added.  I'll be making changes to the layout. Also, larger
waves won't fit in the space so I'll need to scale the bar
sizes. The same is true for the spectrum display.

--  The spectrum display has the longer period red bands on
the bottom which is the opposite of what I did in my earlier
work. This makes arriving swell components easier to see because
they aren't being bumped up by the bands below it. I like it 
better this way.

--  In the Direction display the pointers change size in 
proportion to the percentage of energy that's in that band.
If 100% was in a band to pointer would be as long as the 
whole circle but that won't happen often, if ever. I set a
minimum size so each pointer will always be viable since
there is always direction data for all bands. I also draw
the pointers starting with the biggest so smaller ones won't
be hidden.