I map 🗺️ & graph 📈 data 🈸
Published
Edited
Feb 25, 2019
8 stars
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Chicago Crimes Hexgrid Map
Also listed in…
Chicago Crimes
hexgrid = d3.hexgrid()
.extent([mapWidth, mapHeight])
.geography(geo)
.projection(projection)
.pathGenerator(path)
.hexRadius(blockRadius)
hexagons = hexgrid(data, ['index'])
grid = hexagons.grid
svg = drawHexgrid(data)
dataUrl = 'https://raw.githubusercontent.com/RandomFractals/ChicagoCrimes/master/data/2018/chicago-crimes-2018.arrow'
dataTable = loadData(dataUrl).then(buffer => arrow.Table.from(new Uint8Array(buffer)))
days = Math.ceil((endDate - startDate) / millisPerDay)
millisPerDay = 24 * 60 * 60 * 1000
function dayToDate(day) {
return new Date(startDate.getTime() + day*millisPerDay)
}
fields = dataTable.schema.fields.map(f => f.name)
data = filterData(dataTable, crimeType,
new Date(startDate.getTime() + startDay*millisPerDay),
new Date(startDate.getTime() + endDay*millisPerDay))
function filterData(dataTable, crimeType, startDate, endDate) {
let lat, lng, block, type, info, date, results = [];
const dataFilter = arrow.predicate.custom(i => {
const date = toDate(dataTable.getColumn('Date').get(i));
const primaryType = dataTable.getColumn('PrimaryType').get(i);
return date >= startDate && date <= endDate &&
(crimeType === '' || primaryType === crimeType);
}, b => 1);
dataTable.filter(dataFilter)
.scan((index) => {
results.push({
'lat': lat(index),
'lng': lng(index),
index,
//'info': `${block(index)}<br />${type(index)}<br />${info(index)}<br />${toDate(date(index)).toLocaleString()}`
});
}, (batch) => {
lat = arrow.predicate.col('Latitude').bind(batch);
lng = arrow.predicate.col('Longitude').bind(batch);
block = arrow.predicate.col('Block').bind(batch);
type = arrow.predicate.col('PrimaryType').bind(batch);
info = arrow.predicate.col('Description').bind(batch);
date = arrow.predicate.col('Date').bind(batch);
}
);
return results;
}
function getDataPoints(mapPoints) {
const dataPoints = [];
mapPoints.map(point => {
const dataRow = dataTable.get(point.index);
const dataPoint = {
// from fields
block: dataRow.get(2),
location: dataRow.get(3).toLowerCase(),
type: dataRow.get(4),
info: dataRow.get(5).toLowerCase(),
arrested: dataRow.get(6),
domestic: dataRow.get(7),
date: toDate(dataRow.get(9))
}
dataPoints.push(dataPoint);
});
return dataPoints;
}
d3 = require('d3-fetch', 'd3-geo', 'd3-geo-projection', 'd3-hexgrid',
'd3-scale', 'd3-scale-chromatic', 'd3-format', 'd3-time-format', 'd3-array', 'd3-selection')
arrow = require('apache-arrow@0.3.1')
import {loadData, toDate} from '@randomfractals/apache-arrow'
import {slider, select} from "@jashkenas/inputs"
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