{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "Slope graph showing the change in yield for different barley sites. It shows the error in the year labels for the Morris site.",
  "background": "white",
  "padding": 5,
  "height": 200,
  "style": "cell",
  "data": [
    {
      "name": "source_0",
      "url": "https://raw.githubusercontent.com/vega/vega-datasets/master/data/barley.json",
      "format": {"type": "json"},
      "transform": [
        {
          "type": "aggregate",
          "groupby": ["year", "site"],
          "ops": ["mean"],
          "fields": ["yield"],
          "as": ["mean_yield"]
        }
      ]
    }
  ],
  "signals": [
    {"name": "x_step", "value": 50},
    {
      "name": "width",
      "update": "bandspace(domain('x').length, 1, 0.5) * x_step"
    }
  ],
  "marks": [
    {
      "name": "pathgroup",
      "type": "group",
      "from": {
        "facet": {
          "name": "faceted_path_main",
          "data": "source_0",
          "groupby": ["site"]
        }
      },
      "encode": {
        "update": {
          "width": {"field": {"group": "width"}},
          "height": {"field": {"group": "height"}}
        }
      },
      "marks": [
        {
          "name": "marks",
          "type": "line",
          "style": ["line"],
          "sort": {"field": "datum[\"year\"]"},
          "from": {"data": "faceted_path_main"},
          "encode": {
            "update": {
              "stroke": {"scale": "color", "field": "site"},
              "description": {
                "signal": "\"year: \" + (isValid(datum[\"year\"]) ? datum[\"year\"] : \"\"+datum[\"year\"]) + \"; Mean of yield: \" + (format(datum[\"mean_yield\"], \"\")) + \"; site: \" + (isValid(datum[\"site\"]) ? datum[\"site\"] : \"\"+datum[\"site\"])"
              },
              "x": {"scale": "x", "field": "year"},
              "y": {"scale": "y", "field": "mean_yield"},
              "defined": {
                "signal": "isValid(datum[\"mean_yield\"]) && isFinite(+datum[\"mean_yield\"])"
              }
            }
          }
        }
      ]
    }
  ],
  "scales": [
    {
      "name": "x",
      "type": "point",
      "domain": {"data": "source_0", "field": "year", "sort": true},
      "range": {"step": {"signal": "x_step"}},
      "padding": 0.5
    },
    {
      "name": "y",
      "type": "linear",
      "domain": {"data": "source_0", "field": "mean_yield"},
      "range": [{"signal": "height"}, 0],
      "nice": true,
      "zero": true
    },
    {
      "name": "color",
      "type": "ordinal",
      "domain": {"data": "source_0", "field": "site", "sort": true},
      "range": "category"
    }
  ],
  "axes": [
    {
      "scale": "y",
      "orient": "left",
      "gridScale": "x",
      "grid": true,
      "tickCount": {"signal": "ceil(height/40)"},
      "domain": false,
      "labels": false,
      "aria": false,
      "maxExtent": 0,
      "minExtent": 0,
      "ticks": false,
      "zindex": 0
    },
    {
      "scale": "x",
      "orient": "bottom",
      "grid": false,
      "title": "year",
      "labelAlign": "right",
      "labelAngle": 270,
      "labelBaseline": "middle",
      "zindex": 0
    },
    {
      "scale": "y",
      "orient": "left",
      "grid": false,
      "title": "Mean of yield",
      "labelOverlap": true,
      "tickCount": {"signal": "ceil(height/40)"},
      "zindex": 0
    }
  ],
  "legends": [{"stroke": "color", "symbolType": "stroke", "title": "site"}]
}