Tuesday, August 16, 2011

A Javascript worldview for surface temp.

You may have noticed that I generally prefer simple spherical (orthographic) projections for displaying global fields. Even though it takes several projections to convey all the information.

But I use lat/lon maps for comparisons, and more recently, Hammer projections for comparison with NOAA and MP.

Spherical projections take up space, but this can be resolved by creating a poor man's Google Earth (OK, GE is free) with Javascript. In the plot below, of the July temperature data using GISS's colors and baseline (1951-80), you'll see a pattern of squares, top left. This corresponds to eight views. The directions are as if the earth was encased in a cube, with one apex above the N pole. The views are from the directions of the eight corners. N Pole is the square at the top, the next three are around near the Tropic of Cancer, etc. Just click - the red square marks where you are.
Picture below the jump

Below the jump - same for NOAA

This time, for variety, I've positioned the views differently. The viewing cube is tangent to the pole, so the foci are points along a N and S latitude, at about 40°. The squares to click on follow that pattern.(Due to a slight inadequacy in the current JS, please don't click on this one before clicking on the top one).


  1. It's not GE .. but excellent interactive visualisation for this data!!

  2. It's a big improvement, but it would be better if you could click and drag to rotate the globe in the manner of Google Earth when zoomed out.

    I have no idea how difficult this would be to implement though.

  3. Anon,
    On dragging, the main thing is that it is only reasonable (in terms of downloadable resources) to provide about 8 views (you'll notice a pause when you first click, which is the downloading). So there wouldn't be a continuous response.

    It would be possible to make dragging work in a jerky way - say by flipping one view every cm of drag. But I don't think it would be very intuitive.

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