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kbdw's avatar
kbdw
New Member
3 years ago

Wind Direction Aster Plot

Hello,   I am trying to create an aster plot (or similar) showing wind direction at a weather station. The measurements were every 15 minutes, from which I have created an average daily measurement...
Need Help
dm-p's avatar
dm-p
Super User
3 years ago

Updated version with a ThetaMid column (which is just the angle value in radians for the text mark):

 

{
  "data": {"name": "dataset"},
  "layer": [
    {
      "mark": {
        "type": "arc",
        "innerRadius": 20,
        "stroke": "#444"
      }
    },
    {
      "mark": {
        "type": "text",
        "radiusOffset": 50
      },
      "encoding": {
        "text": {
          "field": "Direction",
          "type": "nominal"
        },
        "theta": {
          "value": {
            "expr": "datum['ThetaMid']"
          }
        }
      }
    }
  ],
  "encoding": {
    "theta": {
      "value": {
        "expr": "datum['Theta']"
      },
      "type": "quantitative",
      "stack": false
    },
    "theta2": {
      "value": {
        "expr": "datum['Theta2']"
      },
      "type": "quantitative"
    },
    "radius": {
      "field": "Sum of Count",
      "scale": {
        "type": "sqrt",
        "zero": true
      }
    },
    "color": {
      "field": "Direction",
      "type": "nominal"
    }
  }
}

 

Cheers,

 

Daniel

lbendlin's avatar
lbendlin
Super User
3 years ago

Thank you for the insights. Need to bottle this up somehow. You're not planning to write a book or something on the finer details of data binding by any chance?