Support GeoJSON polygon issue #79 / Alex Bol

Computational geometry and data visualization

Published

Edited

Jan 28, 2021

md`# Support GeoJSON polygon issue #79`

data = {

let { polygon } = Flatten;

let geoJSON = {

type: "MultiPolygon",

coordinates: [

[[[102.0, 2.0], [103.0, 2.0], [103.0, 3.0], [102.0, 3.0], [102.0, 2.0]]],

[

[[100.0, 0.0], [101.0, 0.0], [101.0, 1.0], [100.0, 1.0], [100.0, 0.0]],

[[100.2, 0.2], [100.2, 0.8], [100.8, 0.8], [100.8, 0.2], [100.2, 0.2]]

]

};

const poly = polygon(geoJSON.coordinates);

return [poly, ...poly.vertices];

}

transformed_data = {

let m = data2center(data,width,height);

let transformed_data = data.map(shape => shape.transform(m))

return transformed_data;

}

stageBox = new Flatten.Box(0,0,width,height)

height = 400

function data2center(data, width, height) {

let {matrix} = Flatten;

let box = data.reduce( (acc,shape) => acc = acc.merge(shape.box), new Flatten.Box() )

let data_width = box.xmax - box.xmin || 400;

let data_height = box.ymax - box.ymin || 400;

let k = Math.min( width / (1.1*data_width), height / (1.1*data_height) );

let tx = width/2 - k*(box.xmin + box.xmax)/2;

let ty = height/2 - k*(box.ymin + box.ymax)/2;

let m = matrix().translate(tx,ty).scale(k,k)

return m;

}

Flatten = require("@flatten-js/core@1.2.20")

d3 = require("d3")

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