问题
I was wonder if it is possible to create a vega/vega-lite visualization , based on time periodic columns. For example , assume that i would like to display a graph of athletics results in a bar/other visualization.
rio-2016-athletics
I have tried to make some changes to simple bar chart bellow. I have edited only the "amount" column in order to display time-period results:
"data": [
{
"name": "table",
"values": [
{"category": "1", "amount": 1:42.15},
{"category": "2", "amount": 1:42.61},
{"category": "3", "amount": 1:42.93},
{"category": "4", "amount": 1:43.41}
]
}
]
I got the following error message: [Error] Unexpected token : in JSON at position 208 and line 12
Can one advise how to display time periodic column IN THE FORMAT THAT I AM LOOKING FOR (mm:ss.ms)
The original code was:
{
"$schema": "https://vega.github.io/schema/vega/v5.json",
"width": 400,
"height": 200,
"padding": 5,
"data": [
{
"name": "table",
"values": [
{"category": "1", "amount": 42.15},
{"category": "2", "amount": 42.61},
{"category": "3", "amount": 42.93},
{"category": "4", "amount": 43.41}
]
}
],
"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"
}
],
"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": {"value": "#333"}
},
"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}
]
}
}
}
]
}
回答1:
Your first issue is that you have created invalid JSON: your timestamps need to be quoted. That is, replace 1:42.15
with "1:42.15"
.
As for parsing the dates, this is easiest to do in Vega-Lite. You can use the Data Format value to control how your date strings are interpreted. For example (online editor):
{
"data": {
"values": [
{"category": "1", "amount": "1:42.15"},
{"category": "2", "amount": "1:42.61"},
{"category": "3", "amount": "1:42.93"},
{"category": "4", "amount": "1:43.41"}
],
"format": {"parse": {"amount": "date:'%M:%S.%L'"}}
},
"mark": "point",
"encoding": {
"x": {"field": "category", "type": "ordinal"},
"y": {"field": "amount", "timeUnit": "minutessecondsmilliseconds", "type": "temporal"}
}
}
If you're interested in how this translates to Vega, you can click the "Compiled Vega" tab in the above editor link.
来源:https://stackoverflow.com/questions/59787286/is-it-possible-to-display-vega-vega-lite-bar-based-on-period-time-column