Contour-wasm

Contour
and contour-isobands rust crates,
compiled to WebAssembly, for use in the browser.

Usage

This module exposes two functions:
- isobands(data, width, height, intervals[, options])
- isolines(data, width, height, intervals[, options])

$3

With default values

``js
import * as contours from 'contour-wasm';

const data = [
0, 0, 0, 0,
0, 2, 2, 0,
0, 2, 2, 0,
0, 0, 0, 0,
];

const result = contours.isobands(data, 4, 4, [0, 1.5]);
`

With options

`js
import * as contours from 'contour-wasm';

const data = [
0, 0, 0, 0,
0, 2, 2, 0,
0, 2, 2, 0,
0, 0, 0, 0,
];

const options = {
use_quad_tree: false, // default: true
x_origin: 22.5, // default: 0
y_origin: 22.5, // default: 0
x_step: 45, // default: 1
y_step: -45, // default: 1
}

const result = contours.isobands(data, 4, 4, [0, 1.5], options);
`

$3

With default values

`js
import * as contours from 'contour-wasm';

const data = [
0, 0, 0, 0,
0, 2, 2, 0,
0, 2, 2, 0,
0, 0, 0, 0,
];

const result = contours.isolines(data, 4, 4, [0, 1.5]);
`

With options

`js
import * as contours from 'contour-wasm';

const data = [
0, 0, 0, 0,
0, 2, 2, 0,
0, 2, 2, 0,
0, 0, 0, 0,
];

const options = {
x_origin: 22.5, // default: 0
y_origin: 22.5, // default: 0
x_step: 45, // default: 1
y_step: -45, // default: 1
}

const result = contours.isolines(data, 4, 4, [0, 1.5], options);
`

$3

Performance of isobands function from this module compared to MarchingSquaresJS.isoBands
(which is also the package used internally by turf-isobands).

| Data size (number of points) | Number of intervals | MarchingSquares.js | contour-wasm |
|------------------------------|---------------------|--------------------|--------------|
| 5307 | 23 | 16ms | 12ms |
| 17608 | 15 | 25ms | 15ms |
| 336960 | 14 | 369ms | 186ms |
| 1010880 | 14 | 832ms | 492ms |

Installation instructions

$3

`bash
npm install contour-wasm
`

Build instructions

> Only for developers. Otherwise, you can use the npm package.

$3

`bash
wasm-pack build
`

$3

`bash
wasm-pack test --headless --firefox
`

$3

`bash
wasm-pack publish
``

Demo

Demonstration page is available at https://mthh.github.io/contour-wasm/.