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<graph> { "version": 2,
"width": 300,
"height": 50,
"data": [
{
// Data is retrieved from the Wikidat Query API (SPARQL).
"name": "table",
"url": "wikidatasparql:///?query=SELECT+%3Finstance+%3FinstanceLabel+%3Fcount+%7B+%7B%0A++++SELECT+%3Finstance+%28COUNT%28DISTINCT+%3Fitem%29+as+%3Fcount%29+%7B%0A++++++++++%3Fitem+wdt%3AP63+wd%3AQ1+.+%0A++++++++++%3Fitem++wdt%3AP7+%3Finstance.%7D%0A++++GROUP+BY+%3Finstance%0A++++%7D%0A+SERVICE+wikibase%3Alabel+%7B+bd%3AserviceParam+wikibase%3Alanguage+%22en%22.+%7D+%7D%0AORDER+BY+DESC%28%3Fcount%29%0ALIMIT+15%0AOFFSET+0",
"format": { "type": "json" },
"transform": [
// sort in descending order using value as the sort key
{"type": "sort","by": "-count"},
// To visualize, use "pie" transformation to add layout_start, layout_end, and layout_mid fields to each {label, value} object
// These fields contain angles at which to start and stop drawing arcs. First element's start will be 0, and last element's end will be 360 degrees (in radians)
{"type": "pie","field": "count"}
]
}
],
// Scales are like functions -- marks use them to convert a data value into a visual value, like x or y coordinate on the graph, or a color value.
"scales": [
{
// This scale will be used to assign a color to each slice, using a palette of 10 colors
"name": "color",
"domain": {"data": "table","field": "instanceLabel"},
"range": "category10",
"type": "ordinal"
}
],
"marks": [
{
// This mark draws the actual pie chart from the data source
// Each element is an arc between layout_start and layout_end angles (as calculated by the pie transformation)
// drawn with a given radius, stroke, and fill.
"from": {"data": "table"},
"type": "arc",
"properties": {
"enter": {
"fill": {"scale": "color","field": "instanceLabel"},
// Use "width" signal divided by 2 for the outer radius
"outerRadius": {"signal": "width", "mult": 0.5},
"startAngle": {"field": "layout_start"},
"endAngle": {"field": "layout_end"},
"stroke": {"value": "white"},
"strokeWidth": {"value": 1}
}
}
},
{
// This mark draws labels around the pie chart after the pie chart has been drawn
"type": "text",
// Before drawing, we need to perform a number of calculations to figure out the exact location and orientation of the text
"from": {
"data": "table",
"transform": [
// For each data point (datum), each of these transformations will be ran in order.
// Formula transformation evaluates the expression and assigns result to the datapoint
// Size of the pie slice, in degrees: sliceSize = (end - start) * 180 / Pi
{ "type": "formula", "field": "sliceSize", "expr": "(datum.layout_end - datum.layout_start)*180/PI" },
// Draw text only if the slice of the arc is more than 2 degrees to avoid overcrowding
{ "type": "filter", "test": "datum.sliceSize > 2" },
// Determine the side of the pie chart we are on - left or right.
{ "type": "formula", "field": "invert", "expr": "datum.layout_mid*180/PI < 180 ? 1 : -1" },
// If on the left, the text should be right-aligned (go from the rim inward)
{ "type": "formula", "field": "align", "expr": "datum.invert > 0 ? 'left' : 'right'" },
// At what angle should the text be drawn relative to the point on the circle
{ "type": "formula", "field": "angle", "expr": "(datum.layout_mid*180/PI)-90*datum.invert" },
// Make font smaller for smaller pie slices
{ "type": "formula", "field": "fontSize", "expr": "datum.sliceSize > 20 ? 13 : (datum.sliceSize > 10 ? 11 : 10)" },
// Make font bold for largest pie slices
{ "type": "formula", "field": "fontWeight", "expr": "datum.sliceSize > 15 ? 'bold' : 'normal'" }
]
},
"properties": {
"enter": {
// Use the fields calculated in the transformation to draw category names
"align": {"field": "align"},
"angle": {"field": "angle"},
"baseline": {"value": "middle"},
"fill": {"value": "black"},
"fontSize": {"field": "fontSize"},
"fontWeight": {"field": "fontWeight"},
"radius": {"signal": "width", "mult": 0.5, "offset": 10},
"text": {"template": "\u007b{datum.count|number:',d' }\u007d"},
"theta": {"field": "layout_mid"}
}
}
}
],
// Show legend, using the scale named "color" as the source.
"legends": [{
"title": "Type of place",
"fill": "color",
"properties": {
"title": { "fontSize": {"value": 14} },
"symbols": { "stroke": {"value": "transparent"} },
"legend": {
"strokeWidth": {"value": 1.5},
// Set new position of the legend relative to the center of the graph, using graph's width & height
"x": {"signal":"width", "mult":0.5, "offset":60},
"y": {"signal":"height", "mult":-0.5}
}
}
}]
} </graph>See it in Wikidata Query Service |