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<script src="https://cdn.jsdelivr.net/npm/vega-embed#6.20.8"></script>
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<body>
<div id="vis"/>
<script>
const spec = {
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"name": "source_0",
"data": {
"values": [
{"Items": "3", "Items_Rate": "0.20", "Month": "Jan-21"},
{"Items": "6", "Items_Rate": "0.40", "Month": "Feb-21"},
{"Items": "2", "Items_Rate": "0.20", "Month": "Mar-21"},
{"Items": "4", "Items_Rate": "0.30", "Month": "Apr-21"},
{"Items": "8", "Items_Rate": "0.45", "Month": "May-21"},
{"Items": "9", "Items_Rate": "0.50", "Month": "Jun-21"},
{"Items": "1", "Items_Rate": "0.10", "Month": "Jul-21"},
{"Items": "5", "Items_Rate": "0.35", "Month": "Aug-21"},
{"Items": "4", "Items_Rate": "0.28", "Month": "Sep-21"},
{"Items": "7", "Items_Rate": "0.37", "Month": "Oct-21"},
{"Items": "1", "Items_Rate": "0.50", "Month": "Nov-21"},
{"Items": "4", "Items_Rate": "0.35", "Month": "Dec-21"}
]
},
"vconcat": [
{
"width": 850,
"height": 250,
"layer": [
{
"mark": {"type": "bar", "size": 50, "tooltip": true},
"transform": [{"filter": {"param": "brush"}}],
"encoding": {
"x": {
"field": "Month",
"type": "ordinal",
"sort": null,
"scale": {"domain": {"param": "brush"}, "zero": true},
"axis": {
"title": "",
"labelAngle": 360,
"tickSize": 20,
"position": 0
}
},
"y": {
"field": "Items",
"type": "quantitative",
"axis": {"tickMinStep": 1}
},
"color": {
"datum": "No. of Items",
"scale": {"range": ["#0065ad"]}
},
"tooltip": [
{"field": "Month", "type": "nominal", "title": "Month"},
{
"field": "Items",
"type": "quantitative",
"title": "No. of Items"
}
]
}
},
{
"mark": {
"type": "line",
"point": {"shape": "square", "size": "50"},
"size": "2",
"tooltip": true
},
"transform": [{"filter": {"param": "brush"}}],
"encoding": {
"x": {
"field": "Month",
"type": "nominal",
"title": "",
"sort": null,
"scale": {"domain": {"param": "brush"}}
},
"y": {
"field": "Items_Rate",
"type": "quantitative",
"title": "Items",
"scale": {"zero": false},
"sort": null
},
"color": {
"datum": "Items Rate",
"scale": {"range": ["black"]},
"legend": {"symbolType": "square"}
},
"tooltip": [
{"field": "Month", "type": "nominal", "title": "Month"},
{
"field": "Items_Rate",
"type": "quantitative",
"title": "Rate"
}
]
}
}
],
"resolve": {
"scale": {
"y": "independent",
"shape": "independent",
"color": "independent",
"size": "independent"
}
}
},
{
"width": "850",
"height": 100,
"mark": "bar",
"params": [
{
"name": "brush",
"select": {"type": "interval", "encodings": ["x"], "translate": true}
}
],
"encoding": {
"x": {
"field": "Month",
"type": "nominal",
"sort": null,
"axis": {"title": "", "labels": false, "ticks": false}
},
"y": {
"field": "Items",
"type": "quantitative",
"axis": {
"tickCount": 3,
"grid": false,
"title": "",
"labels": false,
"ticks": false
}
},
"color": {"value": "#0065ad"}
}
}
],
"config": {
"axisY": {"minExtent": 40},
"legend": {
"orient": "top",
"layout": {"top": {"anchor": "middle"}},
"labelFont": "arial",
"titleFont": "arial"
}
}
};
vegaEmbed("#vis", spec, {mode: "vega-lite"}).then(console.log).catch(console.warn);
</script>
</body>
</html>
It can also be viewed in Vega lite editor here:
https://vega.github.io/editor/#/gist/da859f07e288d51da47a309ef2718ab2/responsive_chart.json
My query is that when I select 4 or more graphs and scroll forwards, everything is working properly. However when I scroll the same backwards, the line graphs becomes incorrect.
Instead of the nearest point creating a line to join the newly visible point, the farthest or the second-last visible graph now is joining the points.
How could I change the code to have only the nearest point join with the new point and not the order of how they became visible?
For example, in the screenshot below, the Sept-21 point should join the Aug-21 point and NOT Nov-21 when I take the scroll backwards.
Thank you for the help.
You need a sort field. I added an index and used that but you can use anything you like.
Editor
{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"name": "source_0",
"data": {
"values": [
{"Items": "3", "Items_Rate": "0.20", "Month": "Jan-21", "Index":1},
{"Items": "6", "Items_Rate": "0.40", "Month": "Feb-21", "Index":2},
{"Items": "2", "Items_Rate": "0.20", "Month": "Mar-21", "Index":3},
{"Items": "4", "Items_Rate": "0.30", "Month": "Apr-21", "Index":4},
{"Items": "8", "Items_Rate": "0.45", "Month": "May-21", "Index":5},
{"Items": "9", "Items_Rate": "0.50", "Month": "Jun-21", "Index":6},
{"Items": "1", "Items_Rate": "0.10", "Month": "Jul-21", "Index":7},
{"Items": "5", "Items_Rate": "0.35", "Month": "Aug-21", "Index":8},
{"Items": "4", "Items_Rate": "0.28", "Month": "Sep-21", "Index":9},
{"Items": "7", "Items_Rate": "0.37", "Month": "Oct-21", "Index":10},
{"Items": "1", "Items_Rate": "0.50", "Month": "Nov-21", "Index":11},
{"Items": "4", "Items_Rate": "0.35", "Month": "Dec-21", "Index":12}
]
},
"vconcat": [
{
"width": 850,
"height": 250,
"layer": [
{
"mark": {"type": "bar", "size": 50, "tooltip": true},
"transform": [{"filter": {"param": "brush"}}],
"encoding": {
"x": {
"field": "Month",
"type": "ordinal",
"sort": null,
"scale": {"domain": {"param": "brush"}, "zero": true},
"axis": {
"title": "",
"labelAngle": 360,
"tickSize": 20,
"position": 0
}
},
"y": {
"field": "Items",
"type": "quantitative",
"axis": {"tickMinStep": 1}
},
"color": {"datum": "No. of Items", "scale": {"range": ["#0065ad"]}},
"tooltip": [
{"field": "Month", "type": "nominal", "title": "Month"},
{
"field": "Items",
"type": "quantitative",
"title": "No. of Items"
}
]
}
},
{
"mark": {
"type": "line",
"point": {"shape": "square", "size": "50"},
"size": "2",
"tooltip": true
},
"transform": [{"filter": {"param": "brush"}}],
"encoding": {
"x": {
"field": "Month",
"type": "nominal",
"title": "",
"sort": {"field": "Index"},
"scale": {"domain": {"param": "brush"}}
},
"y": {
"field": "Items_Rate",
"type": "quantitative",
"title": "Items",
"scale": {"zero": false},
"sort": null
},
"color": {
"datum": "Items Rate",
"scale": {"range": ["black"]},
"legend": {"symbolType": "square"}
},
"tooltip": [
{"field": "Month", "type": "nominal", "title": "Month"},
{"field": "Items_Rate", "type": "quantitative", "title": "Rate"}
]
}
}
],
"resolve": {
"scale": {
"y": "independent",
"shape": "independent",
"color": "independent",
"size": "independent"
}
}
},
{
"width": "850",
"height": 100,
"mark": "bar",
"params": [
{
"name": "brush",
"select": {"type": "interval", "encodings": ["x"], "translate": true}
}
],
"encoding": {
"x": {
"field": "Month",
"type": "nominal",
"sort": null,
"axis": {"title": "", "labels": true, "ticks": false}
},
"y": {
"field": "Items",
"type": "quantitative",
"axis": {
"tickCount": 3,
"grid": false,
"title": "",
"labels": false,
"ticks": false
}
},
"color": {"value": "#0065ad"}
}
}
],
"config": {
"axisY": {"minExtent": 40},
"legend": {
"orient": "top",
"layout": {"top": {"anchor": "middle"}},
"labelFont": "arial",
"titleFont": "arial"
}
}
}
How can i display the individual bars with a lighter color range based on the graph values. I came to know that vega has sequential multi-hue schemes.
Click here to check Image for MultiColor Scheme. I want to use this color scheme, for different values in the graph. For example, if i have value=3, then in the graph it should display lighter color as compared to the value=10. How can i include the multicolor scheme into the bar graph so it displays the color according to the value. Below is my snippet which i tried, i am actually looking for the color changing according to the amount instead of category. I included color in scales and in fill color in mark. Can someone guide me on how this can be achieved. I am new to this
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"description": "A basic bar chart example, with value labels shown upon mouse hover.",
"width": 400,
"height": 200,
"padding": 5,
"data": [
{
"name": "table",
"values": [
{"category": "A", "amount": 28},
{"category": "B", "amount": 55},
{"category": "C", "amount": 43},
{"category": "D", "amount": 91},
{"category": "E", "amount": 81},
{"category": "F", "amount": 53},
{"category": "G", "amount": 19},
{"category": "H", "amount": 87}
]
}
],
"signals": [
{
"name": "tooltip",
"value": {},
"on": [
{"events": "rect:mouseover", "update": "datum"},
{"events": "rect:mouseout", "update": "{}"}
]
}
],
"scales": [
{
"name": "xscale",
"type": "band",
"domain": {"data": "table", "field": "category"},
"range": "width",
"padding": 0.05,
"round": true
},
{
"name": "yscale",
"domain": {"data": "table", "field": "amount"},
"nice": true,
"range": "height"
},
{
"name": "color",
"type": "ordinal",
"domain": {"data": "table", "field": "category"},
"range": {"scheme": "category10"}
}
],
"axes": [
{ "orient": "bottom", "scale": "xscale" },
{ "orient": "left", "scale": "yscale" }
],
"marks": [
{
"type": "rect",
"from": {"data":"table"},
"encode": {
"enter": {
"x": {"scale": "xscale", "field": "category"},
"width": {"scale": "xscale", "band": 1},
"y": {"scale": "yscale", "field": "amount"},
"y2": {"scale": "yscale", "value": 0}
},
"update": {
"fill": {"value": "steelblue"}
},
"hover": {
"fill": {"value": "red"}
}
}
},
{
"type": "text",
"encode": {
"enter": {
"align": {"value": "center"},
"baseline": {"value": "bottom"},
"fill": {"scale": "color", "field": "category"}
},
"update": {
"x": {"scale": "xscale", "signal": "tooltip.category", "band": 0.5},
"y": {"scale": "yscale", "signal": "tooltip.amount", "offset": -2},
"text": {"signal": "tooltip.amount"},
"fillOpacity": [
{"test": "datum === tooltip", "value": 0},
{"value": 1}
]
}
}
}
]
}
Update: I found out that i have added the fill color in type='text' in mark property, instead of type='rect'
"fill": {"scale": "color", "field": "category"}.
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"description": "A basic bar chart example, with value labels shown upon mouse hover.",
"width": 400,
"height": 200,
"padding": 5,
"data": [
{
"name": "table",
"values": [
{"category": "A", "amount": 28},
{"category": "B", "amount": 55},
{"category": "C", "amount": 43},
{"category": "D", "amount": 91},
{"category": "E", "amount": 81},
{"category": "F", "amount": 53},
{"category": "G", "amount": 19},
{"category": "H", "amount": 87}
]
}
],
"signals": [
{
"name": "tooltip",
"value": {},
"on": [
{"events": "rect:mouseover", "update": "datum"},
{"events": "rect:mouseout", "update": "{}"}
]
}
],
"scales": [
{
"name": "xscale",
"type": "band",
"domain": {"data": "table", "field": "category"},
"range": "width",
"padding": 0.05,
"round": true
},
{
"name": "yscale",
"domain": {"data": "table", "field": "amount"},
"nice": true,
"range": "height"
},
{
"name": "color",
"type": "ordinal",
"domain": {"data": "table", "field": "category"},
"range": {"scheme": "category10"}
}
],
"axes": [
{ "orient": "bottom", "scale": "xscale" },
{ "orient": "left", "scale": "yscale" }
],
"marks": [
{
"type": "rect",
"from": {"data":"table"},
"encode": {
"enter": {
"x": {"scale": "xscale", "field": "category"},
"width": {"scale": "xscale", "band": 1},
"y": {"scale": "yscale", "field": "amount"},
"y2": {"scale": "yscale", "value": 0}
},
"update": {
"fill": {"scale": "color", "field": "category"}
},
"hover": {
"fill": {"value": "red"}
}
}
},
{
"type": "text",
"encode": {
"enter": {
"align": {"value": "center"},
"baseline": {"value": "bottom"}
},
"update": {
"x": {"scale": "xscale", "signal": "tooltip.category", "band": 0.5},
"y": {"scale": "yscale", "signal": "tooltip.amount", "offset": -2},
"text": {"signal": "tooltip.amount"},
"fillOpacity": [
{"test": "datum === tooltip", "value": 0},
{"value": 1}
]
}
}
}
]
}
I see the code to create a Wilkinson Dot Plot in Vega-Lite:
{
"$schema": "https://vega.github.io/schema/vega-lite/v4.json",
"description": "A Wilkinson Dot Plot",
"height": 100,
"data": {
"values": [
10,11,11,11,14,15,17,
22,25,26,28,
33,33,33,34,37
]
},
"transform": [{
"window": [{"op": "rank", "as": "id"}],
"groupby": ["data"]
}],
"mark": {
"type": "circle",
"opacity": 1
},
"encoding": {
"x": {"field": "data", "type": "ordinal"},
"y": {"field": "id", "type": "ordinal", "axis": null, "sort": "descending"}
}
}
Creates a plot grouping the exact numbers, but I'd like the output to be by the first digit so really theres 7 vertical dots for 1, 4 vertical dots for 2, and 5 vertical dots for 3. I tried adding calculation: "str.map(x => x.charAt(0))" to the transform array so I could group by that, but was unsuccessful in my execution. Any ideas appreciated!
You were on the right track, except that calculate transforms cannot use arbitrary javascript code, but only the subset made available in Vega Expressions. So, for example, you could do something like this (vega editor):
{
"data": {
"values": [10, 11, 11, 11, 14, 15, 17, 22, 25, 26, 28, 33, 33, 33, 34, 37]
},
"transform": [
{"calculate": "floor(datum.data / 10)", "as": "data"},
{
"window": [{"op": "rank", "field": "data", "as": "id"}],
"groupby": ["data"]
}
],
"mark": {"type": "circle", "opacity": 1},
"encoding": {
"x": {"field": "data", "type": "ordinal"},
"y": {"field": "id", "type": "ordinal", "axis": null, "sort": "descending"}
}
}
Is it possible to create parallel coordinates in Vega-Lite? I'm looking for a simple yet powerful plotting library for JavaScript and support for parallel coordinates is a requirement.
I have googled it but only found how to do it in Vega.
Yes, you can create a parallel coordinates plot in Vega-Lite by combining a window transform and a fold transform. Here is an example with the Iris dataset (vega editor link):
{
"data": {
"url": "data/iris.json"
},
"transform": [
{"window": [{"op": "count", "as": "index"}]},
{"fold": ["petalLength", "petalWidth", "sepalLength", "sepalWidth"]}
],
"mark": "line",
"encoding": {
"color": {"type": "nominal", "field": "species"},
"detail": {"type": "nominal", "field": "index"},
"opacity": {"value": 0.3},
"x": {"type": "nominal", "field": "key"},
"y": {"type": "quantitative", "field": "value"}
},
"width": 600,
"height": 300
}
Notice we use a window transform to construct an index, followed by a fold transform to restructure the data for plotting.
Building on #jakevdp's answer, here is an improved version that normalizes each variables and manually draw axes with rule, text and tick marks.
Note that parallel coordinates are often useful when you have interactivity though, so there is more work to be done here.
{
"data": {
"url": "data/iris.json"
},
"width": 600,
"height": 300,
"transform": [
{"window": [{"op": "count", "as": "index"}]},
{"fold": ["petalLength", "petalWidth", "sepalLength", "sepalWidth"]},
{
"window": [
{"op": "min", "field": "value", "as": "min"},
{"op": "max", "field": "value", "as": "max"}
],
"frame": [null, null],
"groupby": ["key"]
},
{
"calculate": "(datum.value - datum.min) / (datum.max-datum.min)",
"as": "norm_val"
},
{
"calculate": "(datum.min + datum.max) / 2",
"as": "mid"
}
],
"layer": [{
"mark": {"type": "rule", "color": "#ccc", "tooltip": null},
"encoding": {
"detail": {"aggregate": "count", "type": "quantitative"},
"x": {"type": "nominal", "field": "key"}
}
}, {
"mark": "line",
"encoding": {
"color": {"type": "nominal", "field": "species"},
"detail": {"type": "nominal", "field": "index"},
"opacity": {"value": 0.3},
"x": {"type": "nominal", "field": "key"},
"y": {"type": "quantitative", "field": "norm_val", "axis": null},
"tooltip": [{
"field": "petalLength"
}, {
"field": "petalWidth"
}, {
"field": "sepalLength"
}, {
"field": "sepalWidth"
}]
}
},{
"encoding": {
"x": {"type": "nominal", "field": "key"},
"y": {"value": 0}
},
"layer": [{
"mark": {"type": "text", "style": "label"},
"encoding": {
"text": {"aggregate": "max", "field": "max", "type": "quantitative"}
}
}, {
"mark": {"type": "tick", "style": "tick", "size": 8, "color": "#ccc"}
}]
},{
"encoding": {
"x": {"type": "nominal", "field": "key"},
"y": {"value": 150}
},
"layer": [{
"mark": {"type": "text", "style": "label"},
"encoding": {
"text": {"aggregate": "min", "field": "mid", "type": "quantitative"}
}
}, {
"mark": {"type": "tick", "style": "tick", "size": 8, "color": "#ccc"}
}]
},{
"encoding": {
"x": {"type": "nominal", "field": "key"},
"y": {"value": 300}
},
"layer": [{
"mark": {"type": "text", "style": "label"},
"encoding": {
"text": {"aggregate": "min", "field": "min", "type": "quantitative"}
}
}, {
"mark": {"type": "tick", "style": "tick", "size": 8, "color": "#ccc"}
}]
}],
"config": {
"axisX": {"domain": false, "labelAngle": 0, "tickColor": "#ccc", "title": false},
"view": {"stroke": null},
"style": {
"label": {"baseline": "middle", "align": "right", "dx": -5, "tooltip": null},
"tick": {"orient": "horizontal", "tooltip": null}
}
}
}
I have a line chart, quite basic (see below for a simplified example that works on the Vega Editor). Basically, it draws lines, the X axis is successive dates, the Y axis is some numerical values.
I am trying to add labels for some of the data points on the line, with the value of Y at that point. Only for some of the data points, because some charts can be for over a year, so there can be hundreds of days (X values).
This is by the way how labels are put on the X axis automatically by Vega. If there are too many X values, it does not display every day, it says e.g. "Jan 1", then "Jan 8", then "Jan 15", etc. (nice one!)
Just for reference, with C3 (a charting library for D3), I used the following to draw one label out of every 7 data point:
data: {
json: data.data,
type: 'spline',
labels: {
format: function(v, id, i, j) {
if ( i % 7 === 3 ) {
return d3.format('.2f')(v);
}
}
...
Unfortunately, I have no idea where to start. I did not find any such example, and could not find anything related in the documentation.
Just for reference, here is an example chart to which I'd like to add these labels:
{
"$schema": "https://vega.github.io/schema/vega/v3.json",
"width": 500,
"height": 250,
"autosize": {
"type": "fit",
"resize": true
},
"data": [{
"name": "table",
"format": {
"parse": {
"date": "date",
"value": "number"
}
},
"values": [
{ "date": "2017-09-01", "value": "12.34", "what": "one" },
{ "date": "2017-09-01", "value": "4.34", "what": "two" },
{ "date": "2017-09-02", "value": "13.34", "what": "one" },
{ "date": "2017-09-02", "value": "13.34", "what": "two" },
{ "date": "2017-09-03", "value": "4.34", "what": "one" },
{ "date": "2017-09-03", "value": "15.34", "what": "two" },
{ "date": "2017-09-04", "value": "15.34", "what": "one" },
{ "date": "2017-09-04", "value": "5.34", "what": "two" },
{ "date": "2017-09-05", "value": "16.34", "what": "one" },
{ "date": "2017-09-05", "value": "6.34", "what": "two" },
{ "date": "2017-09-06", "value": "17.34", "what": "one" },
{ "date": "2017-09-06", "value": "17.34", "what": "two" },
{ "date": "2017-09-07", "value": "18.34", "what": "one" },
{ "date": "2017-09-07", "value": "8.34", "what": "two" },
{ "date": "2017-09-08", "value": "18.34", "what": "one" },
{ "date": "2017-09-08", "value": "14.34", "what": "two" },
{ "date": "2017-09-09", "value": "9.34", "what": "one" },
{ "date": "2017-09-09", "value": "14.34", "what": "two" },
{ "date": "2017-09-10", "value": "20.34", "what": "one" },
{ "date": "2017-09-10", "value": "4.34", "what": "two" }
]
}],
"scales": [{
"name": "x",
"type": "utc",
"range": "width",
"domain": {"data": "table", "field": "date"}
}, {
"name": "y",
"type": "linear",
"range": "height",
"nice": true,
"zero": true,
"domain": {"data": "table", "field": "value"}
}, {
"name": "color",
"type": "ordinal",
"range": "category",
"domain": {"data": "table", "field": "what"}
}],
"axes": [{
"orient": "bottom",
"scale": "x",
"encode": {
"labels": {
"interactive": true,
"update": {
"fill": {"value": "steelblue"},
"angle": {"value": 50},
"fontSize": {"value": 14},
"align": {"value": "left"},
"baseline": {"value": "middle"},
"dx": {"value": 3}
},
"hover": {
"fill": {"value": "firebrick"}
}}}
}, {
"orient": "left",
"scale": "y"
}],
"marks": [{
"type": "group",
"from": {
"facet": {
"name": "series",
"data": "table",
"groupby": "what"
}
},
"marks": [{
"type": "line",
"from": {"data": "series"},
"encode": {
"enter": {
"x": {"scale": "x", "field": "date"},
"y": {"scale": "y", "field": "value"},
"stroke": {"scale": "color", "field": "what"},
"strokeWidth": {"value": 2}
},
"update": {
"interpolate": {"value": "monotone"},
"fillOpacity": {"value": 1}
},
"hover": {
"fillOpacity": {"value": 0.5}
}
}
}]
}]
}
Vega has a property called tickCount that can be added to your axes definitions. Adding this to your y-axis must solve your case:
{
"orient": "left",
"scale": "y",
"tickCount": 4
}
You could use a signal as well if it should be dynamic.
The feature is even more powerful than illustrated. Go check out the docs for other options in below link:
https://vega.github.io/vega/docs/axes/