How do I format currency in Vega-Lite? - data-visualization

I'm trying to format values as currency in the Vega-Lite editor. I'm attempting to copy the docs but I'm getting a weird error. The Y axis is a numerical value. Passing in a formatting string gives "value expected".
Here's the json:
{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"description": "Protocol Chart",
"width": 500,
"height": 225,
"data": {
"values": [
{
"asset": "eth",
"time": "2021-06-15T00:00:00Z",
"ReferenceRateUSD": "2577.04473863238"
},
{
"asset": "eth",
"time": "2021-06-16T00:00:00Z",
"ReferenceRateUSD": "2552.74103641146"
},
{
"asset": "eth",
"time": "2021-06-17T00:00:00Z",
"ReferenceRateUSD": "2360.99938690824"
}
]
},
"config": {
"view": {
"stroke": "transparent"
}
},
"mark": "line",
"encoding": {
"x": {
"axis": {
"domainColor": "#DDD",
"grid": false,
"labelColor": "#AEAEAE",
"ticks": false,
"labelPadding": 10
},
"field": "time",
"type": "temporal",
"title": ""
},
"y": {
"axis": {
"labelOffset": 2,
"domainColor": "white",
"labelColor": "#AEAEAE",
"ticks": false,
"labelPadding": 10,
"format": '$.2f'
},
"field": "ReferenceRateUSD",
"type": "quantitative",
"title": "",
"scale": {
"zero": false
}
},
"color": {
"field": "doesntmatter",
"type": "nominal",
"legend": null,
"scale": {
"range": ["#91DB97"]
}
}
}
}
What am I missing here? How do I get it to accept my formatting string?

"$.2f" looks like a the correct d3-format string for currency, but note that this is only valid if the associated formatType is "number" (see axis label docs).
Since you did not include a full reproducible example of the problem you're seeing, I can only venture a guess that your data type is not numeric, and this is why the formatting is failing. If that's not the case, I'd suggest editing your question to provide a complete example of the error you're seeing.
Edit: your full example appears to work correctly with the current version of vega/vega-lite (view in editor):
Perhaps you need to update your vega/vega-lite libraries?

Related

How would I add a tooltip to a multi series line chart

I'm new to WebStorm and vega/vegalite and I am working on creating a visual with different types of gasoline and their prices from 1996-2020.
I've been able to create a graph with all of the information, but it's pretty hard to discern anything.
I've been going over the Vega-Lite documentation and I see that that I can use tooltips to zoom into the graphic. I tried implementing it, but I don't think I quite understand the scope of some of the properties.
Could someone show me how they might approach this task? Or perhaps even recommend videos or websites that might help me better understand how to do?
{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"description": "Area charts of stock prices, with an interactive overview and filtered detail views.",
"width": 720,
"height": 480,
"padding": 5,
"data": {
"name": "gas_prices",
"url": "data/testInfo.csv",
"format": {"type": "csv", "parse": {"A1": "number", "date": "date"}}
},
"repeat": {
"layer": ["A1","A2","A3","R1","R2","R3","M1","M2","M3","P1","P2","P3","D1"]
},
"spec": {
"mark": "line",
"encoding": {
"x": {
"timeUnit": "yearmonth",
"title": "Date",
"field": "date"
},
"y": {
"field": {"repeat":"layer"},
"title": "Gas Prices",
"type": "quantitative"
},
"color": {
"datum": {"repeat": "layer"},
"type": "nominal"
}
}
}
}
You can refer the documentation for tooltip, which says about the options available to enable tooltips on your chart.
Below is a sample config having default tooltip or refer editor:
{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"repeat": ["Horsepower", "Miles_per_Gallon", "Acceleration", "Displacement"],
"columns": 2,
"spec": {
"data": {"url": "data/cars.json"},
"mark": {"type": "bar", "tooltip": true},
"encoding": {
"x": {"field": {"repeat": "repeat"}, "bin": true},
"y": {"aggregate": "count"},
"color": {"field": "Origin"}
}
}
}
To have tooltips with some customizations, you can refer below code or editor:
{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"repeat": ["Horsepower", "Miles_per_Gallon", "Acceleration", "Displacement"],
"columns": 2,
"spec": {
"data": {"url": "data/cars.json"},
"mark": "bar",
"encoding": {
"tooltip": [
{"aggregate": "count", "title": "YAxis"},
{"field": {"repeat": "repeat"}, "title": "myXAxis"}
],
"x": {"field": {"repeat": "repeat"}, "bin": true},
"y": {"aggregate": "count"},
"color": {"field": "Origin"}
}
}
}

Why column facet in Vega Lite not working properly with layer?

I'm trying to create 3 column plot and it works when there's no layer.
But when I add the layer - 3 columns get merged into one plot (open in editor).
How to make it to be separated into 3 columns by the duration field?
CODE
For the plot with the full data please use editor link above.
{
"encoding": {
"column": { "field": "duration", "type": "nominal" },
"x": { "field": "bin_i", "type": "ordinal" }
},
"layer": [
{
"mark": { "type": "bar", "size": 2 },
"encoding": {
"y": { "field": "min", "type": "quantitative" },
"y2": { "field": "max", "type": "quantitative" }
}
},
{
"mark": { "type": "tick" },
"encoding": {
"y": { "field": "mean", "type": "quantitative" }
}
}
],
"data": {
"values": [
{
"bin_i": 1,
"duration": 1,
"max": 1.9642835793718165,
"mean": 1.0781367168962268,
"min": 0.3111818864927448
},
...
]
}
}
A layered chart does not accept a faceted encoding. If you want to facet a layered chart, you should use the facet operator rather than a facet encoding.
For your example, it would look like this (Vega Editor):
{
"facet": {"column": {"field": "duration", "type": "nominal"}},
"spec": {
"encoding": {
"x": {"field": "bin_i", "type": "ordinal"}
},
"layer": [
{
"mark": {"type": "bar", "size": 2},
"encoding": {
"y": {"field": "min", "type": "quantitative"},
"y2": {"field": "max"}
}
},
{
"mark": {"type": "tick"},
"encoding": {
"y": {"field": "mean", "type": "quantitative"}
}
}
]
},
"data": {
"values": [
{
"bin_i": 1,
"duration": 1,
"max": 1.9642835793718165,
"mean": 1.0781367168962268,
"min": 0.3111818864927448
},
...
]
}
}

vega-lite line plot - color not getting applied in transform filter

Vega Editor link here
I've an overlay color change based on filter condition in a multi line chart. Got it working with single line here but 'red' overlay line(along with red dot) doesn't come up with this above multi-line example. Could anyone help me out?
Short answer: your chart is working, except the filtered values are not colored red.
The core issue is that encodings always supersede mark properties, as you can see in this simpler example: editor link
{
"$schema": "https://vega.github.io/schema/vega-lite/v3.json",
"description": "A scatterplot showing horsepower and miles per gallons.",
"data": {"url": "data/cars.json"},
"mark": {"type": "point", "color": "red"},
"encoding": {
"x": {"field": "Horsepower", "type": "quantitative"},
"y": {"field": "Miles_per_Gallon", "type": "quantitative"},
"color": {"field": "Origin", "type": "nominal"},
"shape": {"field": "Origin", "type": "nominal"}
}
}
Notice that although we specify that the mark should have color red, this is overridden by the color encoding. This is by design within Vega-Lite, because encodings are more specific than properties.
Back to your chart: because you specify the color encoding in the parent chart, each individual layer inherits that color encoding, and those colors override the "color": "red" that you specify in the individual layers.
To make it do what you want, you can move the color encoding into the individual layers (and use a detail encoding to ensure the data are still grouped by that field). For example (editor link):
{
"$schema": "https://vega.github.io/schema/vega-lite/v3.json",
"data": {...},
"width": 1000,
"height": 200,
"autosize": {"type": "pad", "resize": true},
"transform": [
{
"window": [{"op": "rank", "as": "rank"}],
"sort": [{"field": "dateTime", "order": "descending"}]
},
{"filter": "datum.rank <= 100"}
],
"layer": [
{
"mark": {"type": "line"},
"encoding": {
"color": {
"field": "name",
"type": "nominal",
"legend": {"title": "Type"}
}
}
},
{
"mark": {"type": "line", "color": "red"},
"transform": [
{
"as": "count",
"calculate": "if(datum.anomaly == true, datum.count, null)"
},
{"calculate": "true", "as": "baseline"}
]
},
{
"mark": {"type": "circle", "color": "red"},
"transform": [
{"filter": "datum.anomaly == true"},
{"calculate": "true", "as": "baseline"}
]
}
],
"encoding": {
"x": {
"field": "dateTime",
"type": "temporal",
"timeUnit": "hoursminutesseconds",
"sort": {"field": "dateTime", "op": "count", "order": "descending"},
"axis": {"title": "Time", "grid": false}
},
"y": {
"field": "count",
"type": "quantitative",
"axis": {"title": "Count", "grid": false}
},
"detail": {"field": "name", "type": "nominal"}
}
}

How to add legend for single or multi series chart in Vega Lite?

How do I add a legend to a basic chart in Vega?
I'm using Vega in the web app where I want all my charts to include a legend even if its a single series.
i.e in Google Sheets it looks like
Since Datum hasn't been implemented yet I added an extra layer as a workaround (This also works for Multi Series Charts by adding additional values into data.values for the rule.)
{
"mark": {
"type": "rule"
},
"data": {
"values": [
{
"color": "Total Units"
}
]
},
"encoding": {
"color": {
"field": "color",
// If you want to update the color of the legend...
"scale": {"range": ["blue", "#000"]},
"sort": false,
"type": "nominal",
"legend": { "title": "" }
}
}
}
Also for those that want to view an example in VegaLite Editor https://vega.github.io/editor/#/
{
"layer": [
{
"mark": "bar",
"data": {
"values": [
{
"goal": 25,
"project": "a",
"score": 25
},
{
"goal": 47,
"project": "b",
"score": 57
},
{
"goal": 30,
"project": "c",
"score": 23
},
{
"goal": 27,
"project": "d",
"score": 19
}
]
},
"encoding": {
"x": {
"type": "nominal",
"field": "project"
},
"y": {
"type": "quantitative",
"field": "score"
}
},
"height": 300,
"width": 400
},
{
"mark": {
"type": "rule"
},
"data": {
"values": [
{
"color": "Goal"
}
]
},
"encoding": {
"color": {
"field": "color",
"sort": false,
"type": "nominal",
"legend": { "title": "" }
}
}
}
]
}

Calculation in vega

I use vega in Kibana.
I select two values from two different index in section "data". But now I need to summarize this values and visualize it in the section "marks". Is anybody know, how can I do this? Now in the section "marks" I use only one value from first "data".
My code is the following:
{
"$schema": "https://vega.github.io/schema/vega/v3.0.json",
"title": {
"text": "Lead time, hr.",
"orient": "bottom"
},
"data": [
{
"name": "source_1",
"url": {
"index": "metrics-bitbucket-*",
"%context_query%": "#timestamp",
"body": {
"size": 0,
"aggs": {
"etb": {
"avg": {
"field": "elapsed_time",
"script": {"source": "_value/3600*10"}
}
}
}
}
},
"format": {"type": "json", "property": "aggregations.etb"}
},
{
"name": "source_2",
"url": {
"index": "metrics-jenkins-*",
"%context_query%": "#timestamp",
"body": {
"size": 0,
"aggs": {
"etj": {
"avg": {
"field": "elapsed_time",
"script": {"source": "_value/3600*10"}
}
}
}
}
},
"format": {"type": "json", "property": "aggregations.etj"}
}
],
"marks": {
"type": "text",
"from": {"data": "source_1"},
"encode": {
"update": {
"text": {"signal": "round(datum.value)/10"},
"fontSize": {"value": 60},
"fontStyle": {"value": "bold"},
"x": {"signal": "width/2-50"},
"y": {"signal": "height/2"}
}
}
}
}
You essentially have two lists of data objects: source1: [{}, {}, ...] and source2: [{}, {}, {}, ...]. When you draw items, you have to specify just one data source. That data source could be the concatenation of the first two, e.g. you create source3 with its source parameter set to ["source1", "source2"], which includes all elements from both, but I suspect this is not what you want here. Rather, you need to merge the data using lookup transform - iterate over the items in one data source, and pull the corresponding values from another data source. Afterwards, add a formula transform to sum the values. The mark would than use the result of the formula for drawing.