Graph/Demo/falkensee

Copied from vega demo, which was modeled on this graph.

<graph>

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	  "version": 2,
	  "width": 500,
	  "height": 250,
	  "padding": "auto",
	  "data": [
	    {
	      "name": "table",
	      "values": [
	        {"year": 1875,"population": 1309},
	        {"year": 1890,"population": 1558},
	        {"year": 1910,"population": 4512},
	        {"year": 1925,"population": 8180},
	        {"year": 1933,"population": 15915},
	        {"year": 1939,"population": 24824},
	        {"year": 1946,"population": 28275},
	        {"year": 1950,"population": 29189},
	        {"year": 1964,"population": 29881},
	        {"year": 1971,"population": 26007},
	        {"year": 1981,"population": 24029},
	        {"year": 1985,"population": 23340},
	        {"year": 1989,"population": 22307},
	        {"year": 1990,"population": 22087},
	        {"year": 1991,"population": 22139},
	        {"year": 1992,"population": 22105},
	        {"year": 1993,"population": 22242},
	        {"year": 1994,"population": 22801},
	        {"year": 1995,"population": 24273},
	        {"year": 1996,"population": 25640},
	        {"year": 1997,"population": 27393},
	        {"year": 1998,"population": 29505},
	        {"year": 1999,"population": 32124},
	        {"year": 2000,"population": 33791},
	        {"year": 2001,"population": 35297},
	        {"year": 2002,"population": 36179},
	        {"year": 2003,"population": 36829},
	        {"year": 2004,"population": 37493},
	        {"year": 2005,"population": 38376},
	        {"year": 2006,"population": 39008},
	        {"year": 2007,"population": 39366},
	        {"year": 2008,"population": 39821},
	        {"year": 2009,"population": 40179},
	        {"year": 2010,"population": 40511},
	        {"year": 2011,"population": 40465},
	        {"year": 2012,"population": 40905},
	        {"year": 2013,"population": 41258},
	        {"year": 2014,"population": 41777}
	      ]
	    },
	    {
	      "name": "annotation",
	      "values": [
	        {"start": 1933,"end": 1945,"text": "Nazi rule"},
	        {"start": 1948,"end": 1989,"text": "GDR (East Germany)"}
	      ]
	    }
	  ],
	  "scales": [
	    {
	      "name": "x",
	      "type": "linear",
	      "range": "width",
	      "zero": false,
	      "domain": {"data": "table","field": "year"}
	    },
	    {
	      "name": "y",
	      "type": "linear",
	      "range": "height",
	      "nice": true,
	      "domain": {"data": "table","field": "population"}
	    },
	    {
	      "name": "color",
	      "type": "ordinal",
	      "domain": {"data": "annotation","field": "text"},
	      "range": ["black","red"]
	    }
	  ],
	  "axes": [
	    {
	      "type": "x",
	      "scale": "x",
	      "format": "d",
	      "title": "Year",
	      "ticks": 15
	    },
	    {
	      "type": "y",
	      "scale": "y",
	      "title": "Population",
	      "grid": true,
	      "layer": "back"
	    }
	  ],
	  "marks": [
	    {
	      "type": "rect",
	      "from": {"data": "annotation"},
	      "properties": {
	        "enter": {
	          "x": {"scale": "x","field": "start"},
	          "y": {"value": 0},
	          "x2": {"scale": "x","field": "end"},
	          "y2": {"signal": "height"},
	          "fill": {"scale": "color","field": "text"},
	          "opacity": {"value": 0.2}
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	    {
	      "type": "line",
	      "from": {"data": "table"},
	      "properties": {
	        "enter": {
	          "interpolate": {"value": "monotone"},
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	          "strokeWidth": {"value": 3}
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	      "type": "symbol",
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	          "fill": {"value": "white"},
	          "size": {"value": 30}
	        }
	      }
	    },
	    {
	      "type": "text",
	      "from": {
	        "data": "table",
	        "transform": [
	          {
	            "type": "aggregate",
	            "summarize": {"year": ["min","max"]}
	          }
	        ]
	      },
	      "properties": {
	        "enter": {
	          "x": {"signal": "width","mult": 0.5},
	          "y": {"value": -10},
	          "text": {
	            "template": "Population of Falkensee from \u007b{datum.min_year}\u007d to \u007b{datum.max_year}\u007d"
	          },
	          "fill": {"value": "black"},
	          "fontSize": {"value": 16},
	          "align": {"value": "center"},
	          "fontWeight": {"value": "bold"}
	        }
	      }
	    }
	  ],
	  "legends": [
	    {
	      "fill": "color",
	      "title": "Period",
	      "properties": {
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	          "shape": {"value": "square"},
	          "opacity": {"value": 0.3}
	        },
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	          "x": {"value": 10},
	          "y": {"value": 5},
	          "fill": {"value": "white"}
	        }
	      }
	    }
	  ]
	}

</graph>