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DelaunayInterpolation

Work in progress

The wind raster layout and interpolation options may evolve. This utility performs explicit CPU sampling; GPU particle advection is implemented separately by ParticleLayer.

DelaunayInterpolation samples or rasterizes a station-interpolated geographic wind field. It is usable in the browser, in Node.js, and as an input-preprocessing step for either graphics backend.

Import​

import {
  createWindField,
  DelaunayInterpolation,
  parseWindData
} from '@deck.gl-community/geo-layers';

Sample a geographic location​

const stations = await fetch('/wind/stations.json').then(response => response.json());
const weather = await fetch('/wind/weather.bin').then(response => response.arrayBuffer());
const field = createWindField(stations, parseWindData(weather, stations.length));

const interpolation = new DelaunayInterpolation({
  field,
  width: 128,
  height: 64
});

const sample = interpolation.sample([-97, 38], 12.5);

if (sample) {
  console.log(sample.direction, sample.speed, sample.temperature);
  console.log(sample.velocity, sample.elevation);
}

Positions outside the triangulated station hull return null. Forecast time interpolates between adjacent frames and wraps at the end of the forecast.

Rasterize a forecast frame​

const raster = interpolation.rasterize(12.5);
const center = (Math.floor(raster.height / 2) * raster.width + Math.floor(raster.width / 2)) * 4;

const direction = raster.data[center];
const speed = raster.data[center + 1];
const temperature = raster.data[center + 2];
const elevation = raster.data[center + 3];

rasterize returns WindRaster: {width, height, data}. Its Float32Array contains row-major [direction, speed, temperature, elevation] pixels. Uncovered pixels are zero.

Constructor properties​

  • field (WindField, required): shared indexed station forecast.
  • width (number, default 256): raster width, at least 2 pixels.
  • height (number, optional): raster height, at least 2 pixels; inferred from the geographic aspect ratio when omitted.

Methods​

  • sample(position, time?): returns a WindSample or null.
  • rasterize(time?): returns one lazily generated WindRaster.

Do not call rasterize for each animated particle or browser frame. ParticleLayer caches the weather textures and performs per-particle movement entirely on the graphics device.

See the wind showcase guide and the Wind Map example.