Btukfyl

How to append a vertical line to a graph and display on a tooltip the data focused?

Something like this:

TASK:

• Add line indicator and tooltip


• Append an invisible div to the vis container, set its class to "tooltip" and use the index.css to define necessary styles (e.g. position)


• Append an indicator line to the viewport


• Append a rectangle and set its class to "interaction-rect" (see index.css). We will use this rectangle to capture the mouse-events


• Whenever there is a mousemove, update the tooltip to show the correct dates and values


• Whenever the mouse leaves the viewport, make the indicator and tooltip disappear

CODE:

/* Retrieve the node of the div element declared within the index.html by its identifier */



var visContainerNode = d3.select("#vis-container");



// Specify margins such that the visualization is clearly visible and no elements are invisible due to the svg border

var margins = {

    top: 20,

    right: 25,

    bottom: 20,

    left: 50

};



// Specify the width and height of the svg as well as the width height of the viewport of the visualization.

var width = 1200;

var height = 800;

var gapY = 50;

var focusAreaHeight = 600 - margins.top;

var contextAreaHeight = 200 - margins.bottom - gapY;

var visWidth = width - margins.left - margins.right;

var visHeight = focusAreaHeight + contextAreaHeight;



/* Appending an svg element to the vis-container, set its width and height (in pixels), and add it to the vis-container */

var svg = visContainerNode.append("svg").attr("width", width).attr("height", height);

svg.append("defs").append("clipPath")

    .attr("id", "clip")

    .append("rect")

    .attr("width", visWidth)

    .attr("height", visHeight);



// Adding a group element to the svg to realize the margin by translating the group.

var viewport = svg.append("g").attr("transform", "translate(" + margins.left + "," + margins.top + ")");



var dateParser = d3.timeParse('%m %Y');

var dateFormat = d3.timeFormat('%m / %Y');

var curve = d3.curveMonotoneX;



// We use the d3.dsv method, which uses the fetchAPI internally, to retrieve the data

d3.dsv(";", "pr_1991_2015.csv", function (d) {

    return {

        date: dateParser(d.Month + " " + d.Year),

        rain: parseFloat(d.pr),

        temperature: parseFloat(d.tas)

    };

}).then(function (data) {

    console.log("Raw Data:", data);



    // Init Scales

    var xFocus = d3.scaleTime().domain(d3.extent(data, function (d) {

        return d.date;

    })).range([0, visWidth]);

    var yRainFocus = d3.scaleLinear().domain([0, d3.max(data.map(function (d) {

        return d.rain

    }))]).range([focusAreaHeight, 0]);

    var yTempFocus = d3.scaleLinear().domain(d3.extent(data.map(function (d) {

        return d.temperature

    }))).range([focusAreaHeight, 0]);



    // In order to organize our code, we add one group for the focus visualization (the large lien chart)

    var focusVis = viewport.append("g");



    // Initialize a line generator for each line

    var rainLine = d3.line()

        .x(function (d) {

            return xFocus(d.date);

        })

        .y(function (d) {

            return yRainFocus(d.rain);

        })

        .curve(curve);



    var tempLine = d3.line()

        .x(function (d) {

            return xFocus(d.date);

        })

        .y(function (d) {

            return yTempFocus(d.temperature);

        })

        .curve(curve);



    // Append two path elements

    focusVis.append("path")

        .datum(data)

        .attr("class", "line line-rain")

        .attr("d", rainLine);

    focusVis.append("path")

        .datum(data)

        .attr("class", "line line-temp")

        .attr("d", tempLine);



    // Lets add some axis

    var axisG = focusVis.append("g");

    var xAxisFocus = d3.axisBottom(xFocus);

    axisG.append("g")

        .attr("class", "x axis")

        .attr("transform", "translate(0," + focusAreaHeight + ")")

        .call(xAxisFocus);



    axisG.append("g")

        .attr("class", "y axis")

        .call(d3.axisLeft(yTempFocus));



    axisG.append("g")

        .attr("class", "y axis")

        .attr("transform", "translate(" + visWidth + ", 0)")

        .call(d3.axisRight(yRainFocus));



    // Append three text elements to the axisG group and label the axes respectively

    axisG.append("text").text("Temperature").attr("x", -50).attr("y", -5).attr("fill", "red");

    axisG.append("text").text("Rain").attr("x", visWidth - 10).attr("y", -5).attr("fill", "blue");

    axisG.append("text").text("Years").attr("x", visWidth / 2).attr("y", focusAreaHeight - 10);



    // Create the context visualization (small line chart) directly below the focus vis

    // Init scales since range differs

    var xContext = d3.scaleTime().domain(d3.extent(data, function (d) {

        return d.date;

    })).range([0, visWidth]);

    var yContextRain = d3.scaleLinear().domain([0, d3.max(data.map(function (d) {

        return d.rain

    }))]).range([contextAreaHeight, 0]);

    var yContexttemp = d3.scaleLinear().domain(d3.extent(data.map(function (d) {

        return d.temperature

    }))).range([contextAreaHeight, 0]);



    // To organize our code, we add one group for the context visualization

    var contextVis = viewport.append("g").attr("transform", "translate(0," + (focusAreaHeight + gapY) + ")");

    var xAxisContext = d3.axisBottom(xContext);

    contextVis.append("g")

        .attr("class", "x axis")

        .attr("transform", "translate(0," + contextAreaHeight + ")")

        .call(xAxisContext);



    // Init two line generators

    var rainLineContext = d3.line()

        .x(function (d) {

            return xContext(d.date);

        })

        .y(function (d) {

            return yContextRain(d.rain);

        })

        .curve(curve);



    var tempLineContext = d3.line()

        .x(function (d) {

            return xContext(d.date);

        })

        .y(function (d) {

            return yContexttemp(d.temperature);

        })

        .curve(curve);



    // Add the two lines for rain and temperature

    contextVis.append("path")

        .datum(data)

        .attr("class", "line line-rain")

        .attr("d", rainLineContext);

    contextVis.append("path")

        .datum(data)

        .attr("class", "line line-temp")

        .attr("d", tempLineContext);





    /*

    * Add Interactive Features here

    */



    /*

     TASK: Add the brush using the d3.brush function, define the extent and the necessary event functions

     Append a new group element and apply the brush on it using the "call" function

     During the brush and on brush end you want to make sure that the lines are redrawn correctly by setting their "d" attribute

    */



    //





    var brush = d3.brushX()

        .extent([[-10, -10], [width+10, height+10]])

        .on("brush end", brushed);





    var zoom = d3.zoom()

        .scaleExtent([1, Infinity])

        .translateExtent([[0, 0], [width, height]])

        .extent([[0, 0], [width, height]])

        .on("zoom", zoomed);



    contextVis.append("g")

        .attr("class", "brush")

        .call(brush)

        .call(brush.move, xContext.range());







    function brushed() {

        if (d3.event || d3.event.selection)

        var s = d3.event.selection || xContext.range();



        xFocus.domain(s.map(xContext.invert, xContext));

        focusVis.select(".line-rain").attr("d", rainLine);

        focusVis.select(".line-temp").attr("d", tempLine);

        focusVis.select(".x axis").call(xAxisFocus);

        focusVis.select(".zoom").call(zoom.transform, d3.zoomIdentity

            .scale(visWidth / (s[1] - s[0]))

            .translate(-s[0], 0));

    }



    function zoomed() {

        if (d3.event || d3.event.selection)

        var t = d3.event.transform;

        xFocus.domain(t.rescaleX(xContext).domain());

        focusVis.select(".line-rain").attr("d", rainLine);

        focusVis.select(".line-temp").attr("d", tempLine);

        axisG.select(".x axis").call(xAxisFocus);

        contextVis.select(".brush").call(brush.move, xContext.range().map(t.invertX, t));

    }

})