{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "description": "Rotating globe animation depicting earthquake locations",
  "usermeta": {
    "Author": "Andrzej Leszkiewicz",
    "Github": "https://github.com/avatorl/Deneb-Vega/",
    "License": "CC BY 4.0 (Share and Adapt with Attribution)",
    "Data Source URL (topojson)": "https://github.com/topojson/world-atlas",
    "Data Source URL": "https://earthquake.usgs.gov/earthquakes/feed/v1.0/csv.php"
  },
  "width": 500,
  "height": 500,
  "padding": 5,
  "autosize": "pad",
  "background": "#000022",
  "signals": [
    {
      "name": "globeRotationAngle",
      "description": "changes from 0 to -180 and then from 180 to 0",
      "init": "0",
      "on": [
        {
          "events": "timer{100}",
          "update": "globeRotationAngle==-180?180:globeRotationAngle-1"
        }
      ]
    },
    {"name": "backSideColor", "value": "#AAAAAA"}
  ],
  "data": [
    {"name": "sphere", "values": [{"type": "Sphere"}]},
    {
      "name": "worldMap",
      "url": "https://raw.githubusercontent.com/avatorl/Deneb-Vega/main/earthquakes-globe/countries-110m.json",
      "format": {"type": "topojson", "feature": "countries"}
    },
    {
      "name": "earthquakes",
      "url": "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_month.csv",
      "format": {"type": "csv", "parse": "auto", "delimiter": ","},
      "transform": [
        {
          "type": "geopoint",
          "projection": "projection",
          "fields": ["longitude", "latitude"],
          "as": ["x", "y"]
        },
        {"type": "collect", "sort": {"field": ["mag"], "order": ["ascending"]}}
      ]
    }
  ],
  "projections": [
    {
      "name": "projection",
      "scale": 225,
      "type": "orthographic",
      "translate": {"signal": "[width/2, height/2]"},
      "rotate": [{"signal": "-globeRotationAngle"}, 0, 0]
    }
  ],
  "scales": [
    {
      "name": "scaleColor",
      "type": "linear",
      "domain": [2, 6, 9],
      "range": ["white", "yellow", "red"]
    },
    {
      "name": "scaleSize",
      "type": "pow",
      "domain": [0, 2, 6, 9],
      "range": [0.1, 10],
      "exponent": 2
    }
  ],
  "title": {
    "text": {
      "signal": "'Earthquakes with magnitude 2.5+, last 30 days (live feed)'"
    },
    "subtitle": "",
    "subtitlePadding": 5,
    "dy": -10,
    "anchor": "start",
    "color": "#DDDDDD",
    "font": {"value": "Tahoma"},
    "fontSize": {"value": 18},
    "fontWeight": "lighter"
  },
  "legends": [
    {
      "type": "symbol",
      "fill": "scaleColor",
      "orient": "left",
      "tickCount": 8,
      "title": "Magnitude",
      "titleColor": {"signal": "'#DDDDDD'"},
      "titleFont": "Tahoma",
      "titleFontSize": 14,
      "titleFontWeight": "lighter",
      "titleAlign": "center",
      "titleOrient": "top",
      "titlePadding": 20,
      "labelColor": {"signal": "'#DDDDDD'"},
      "labelAlign": "right",
      "labelFontSize": 13,
      "format": ".4",
      "encode": {
        "symbols": {
          "enter": {"size": {"scale": "scaleSize", "signal": "datum.value"}}
        },
        "labels": {"enter": {"dx": {"value": 25}}}
      }
    }
  ],
  "marks": [
    {
      "type": "shape",
      "name": "globe",
      "from": {"data": "sphere"},
      "encode": {
        "update": {
          "fillOpacity": {"value": 0},
          "stroke": {"value": "blue"},
          "strokeWidth": {"value": 5},
          "strokeOpacity": {"value": 0.3}
        }
      },
      "transform": [{"type": "geoshape", "projection": "projection"}]
    },
    {
      "type": "shape",
      "name": "countries",
      "from": {"data": "worldMap"},
      "encode": {
        "update": {
          "fill": {"value": "mintcream"},
          "fillOpacity": {"value": 0.1},
          "stroke": {"value": "white"},
          "strokeWidth": {"value": 0.2}
        }
      },
      "transform": [{"type": "geoshape", "projection": "projection"}]
    },
    {
      "type": "symbol",
      "shape": "circle",
      "from": {"data": "earthquakes"},
      "encode": {
        "update": {
          "tooltip": {"signal": "datum.mag"},
          "xc": {"signal": "datum.x"},
          "yc": {"signal": "datum.y"},
          "fill": {
            "signal": "(abs(globeRotationAngle)<=90?datum.longitude>=(globeRotationAngle-90)&&datum.longitude<=(globeRotationAngle+90)?1:0:globeRotationAngle<-90?datum.longitude>(globeRotationAngle-90+360)||datum.longitude<(globeRotationAngle+90)?1:0:globeRotationAngle>90?datum.longitude>(globeRotationAngle-90)||datum.longitude<(globeRotationAngle-180-90)?1:0:0)==1?scale('scaleColor',datum.mag):backSideColor"
          },
          "opacity": {"value": 1},
          "strokeWidth": {"value": 0},
          "size": {
            "scale": "scaleSize",
            "signal": "(abs(globeRotationAngle)<=90?datum.longitude>=(globeRotationAngle-90)&&datum.longitude<=(globeRotationAngle+90)?1:0:globeRotationAngle<-90?datum.longitude>(globeRotationAngle-90+360)||datum.longitude<(globeRotationAngle+90)?1:0:globeRotationAngle>90?datum.longitude>(globeRotationAngle-90)||datum.longitude<(globeRotationAngle-180-90)?1:0:0)*datum.mag"
          }
        }
      }
    }
  ]
}