Hi everyone and thanks in advance,
I hope someone can point me into the right direction on this.
Why do my values only show up when I mark them as points and not line or area?
Am I missing some form of aggregation? Color?
I suspect Vega draws no connection to the next value in the timeline and thus can't generate an interpolation between them?
{
"$schema": "https://vega.github.io/schema/vega-lite/v4.json",
"data": {
"url": {
"%context%": true,
"%timefield%": "@timestamp",
"index": "default-*",
"body": {"size": 10000, "_source": ["@timestamp", "numericData"]}
},
"format": {"property": "hits.hits"}
},
"transform": [
{"calculate": "toDate(datum._source['@timestamp'])", "as": "time"}
],
"vconcat": [
{
"width": 1200,
"mark": {"type": "area", "line": true, "point": true},
"encoding": {
"x": {
"field": "time",
"scale": {"domain": {"selection": "brush"}},
"type": "temporal",
"axis": {"title": ""}
},
"y": {
"field": "_source.numericData",
"type": "quantitative",
"scale": {"domain": [0, 10]}
}
}
},
{
"width": 1200,
"height": 60,
"mark": {"type": "area", "line": true, "point": true}, // <-- area only leaves the diagram empty
"selection": {"brush": {"type": "interval", "encodings": ["x"]}},
"encoding": {
"x": {"field": "time", "type": "temporal"},
"y": {
"field": "_source.numericData",
"type": "quantitative",
"formatType": "String",
"axis": {"tickCount": 3, "grid": false}
}
}
}
]
}
X: timestamp
Y: integers (float)
I bet there are some crucial setting I'm not seeing from examples and tutorials I'm going through.
Maybe someone has a clue.
Thank you all for your help and support 
"Mark: Area" is not visible