<story><title>A visualization of global weather conditions, forecast by supercomputers</title><url>http://earth.nullschool.net</url></story><parent_chain></parent_chain><comment><author>IvyMike</author><text>Time to whip out the hairy ball theorem: &lt;a href=&quot;https://en.wikipedia.org/wiki/Hairy_ball_theorem&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Hairy_ball_theorem&lt;/a&gt;&lt;p&gt;Yes I heard what I just said.</text></comment>
<story><title>A visualization of global weather conditions, forecast by supercomputers</title><url>http://earth.nullschool.net</url></story><parent_chain></parent_chain><comment><author>adolgert</author><text>The javascript shows they are thinking about this as particle traces of wind velocities. In visualization, the technique is called Line Integral Convolution (LIC). Each line follows the direction of the wind vector, and the overall brightness is the sum of the magnitude of the winds under the line. This particular variant just uses the wind speed at one point under the line. LIC won&amp;#x27;t accidentally miss field singularities like vector-arrow representations, and there are variants that provide smooth animations.&lt;p&gt;It&amp;#x27;s great that we&amp;#x27;ve advanced from needing VTK to being able to do a visualization like this as a live movie, translating GRIB files to JSON.</text></comment>