First, I get a list of all winds blowing on or near the coasts. For each of those, I take the projected vector of the wind onto each neighboring hex. If the angle of the projected vector is $<90^\circ$, I know that it's at least in the right direction to catch a bit of that wind.
From there, I determine $dh$, which is the difference between the heights of the two hexes, source and target. If $dh$ is downhill ($dh<0$), there's no change. Otherwise, the turnaside angle $\theta$ is calculated as \[\theta = \frac{90 \exp\left(r \cdot \mathit{dh}\right)}{90 + \left(\exp\left(r \cdot \mathit{dh}\right) - 1\right)}\], where $r=2\log(89)/5000$ is calculated such that the wind will be totally turned aside $90^\circ$ when the slope is 5000 ft or more.
This is one of those areas that I've still not managed to tweak completely to my satisfaction, but it will be good enough to use for precipitation.
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| Angle of wind vectors (not speed) in summer |
What is the image representing? I'm used to wind being represented as vector maps like in your previous post.
ReplyDeleteThe angle of the wind vector. The vector maps (which I make in SVG) are massive files and really chew up performance. It's easier/quicker to output a simple heatmap but then I can only pick one value to represent, where as the barb notation can show both direction and speed.
DeleteFor now I'm simply using a constant speed so that part isn't really useful.
The rain maps (coming soon) help show the actual movement of wind a bit better.