Insert markers for tweets based on lat/long. Colour coded based on sentiment.

points.js

d3.json('/media/js/points.json', function(err, json) {
    svg.select('#points')
        .selectAll('circle')
        .data(json)
        .enter()
        .append("circle")
        .attr("r",4)
        .style('fill-opacity', 0.7)
        .style('display', function(d) {
            if (d.dd == base_date.getDate() && d.mm == base_date.getMonth()+1) {
                return ''
            }
            return 'none'
        })
        .style('fill', function(d) {
            key = d.mm+'-'+d.dd
            if (!sentiment[key]) {
                sentiment[key] = {pos:0, neg:0}
            }
            if (d.sentiment == 'pos') {
                sentiment[key]['pos'] += 1
                return 'blue'
            } else {
                sentiment[key]['neg'] += 1
                return 'red'
            }
        })
        .style('stroke', '#fff')
        .attr("transform", function(d) {return "translate(" + projection([d.lng, d.lat]) + ")";})
})