vega_line_plot_v2.json

{
  "$schema": "https://vega.github.io/schema/vega/v5.json",
  "width": 500,
  "height": 200,
  "padding": 5,

  "signals": [
    {
      "name": "Ville",
      "value": "toulouse",
      "bind": {
        "input": "select",
        "options": [
          "nice",
          "toulouse",
          "montpellier",
          "bordeaux",
          "cannes",
          "toulon",
          "aix-en-provence",
          "nimes",
          "lille",
          "paris-16eme",
          "rouen"
        ]
      }
    }
  ],

  "data": [
    {
      "name": "table",
      "url": "https://raw.githubusercontent.com/klopstock-dviz/immo_vis/master/dataset_vega.csv",
      "format": {"type": "csv", "delimiter": ","}
    },

  {
    "name": "data_filtre1",
    "source": "table",      
    "transform": 
    [
      {"type": "filter", "expr":  "datum.type_annonceur != 'Constructeur maisons' "},
      {"type": "filter", "expr":  "datum.type_annonceur != '' "},
      {"type": "filter", "expr":  "indexof([\"Vente\",\"prestige\", \"investment\"], datum[\"typedetransaction\"]) !== -1"},
      {"type": "filter", "expr":  "datum.ville === Ville"},
      {"type": "formula", "as": "prix_m_2", "expr": "(datum.prix_bien) / datum.surface"}
    ]
  },    

      {
        "name": "prix_m2_med_par_nb_pieces",
        "source": "data_filtre1",      
        "transform": [
          {
          "type": "aggregate",
          "groupby": ["ville","type_annonceur", "nb_pieces"],
          "fields": ["prix_m_2", "nb_pieces", "surface"],
          "ops": ["median", "count", "median"],
          "as": ["prix_m2_median", "nb_log"]
          },
          {
          "type": "collect",
          "sort": {"field": ["nb_pieces"]}
          },
          {"type": "filter", "expr":  "datum.nb_log > 2"}
        ]
      }
  ],

  "scales": [
    {
      "name": "x",
      "type": "point",
      "range": "width",
      "domain": {"data": "prix_m2_med_par_nb_pieces", "field": "nb_pieces"}
    },
    {
      "name": "y",
      "type": "linear",
      "range": "height",
      "nice": true,
      "zero": true,
      "domain": {"data": "prix_m2_med_par_nb_pieces", "field": "prix_m2_median"}
    },
    {
      "name": "color",
      "type": "ordinal",
      "range": "category",
      "domain": {"data": "prix_m2_med_par_nb_pieces", "field": "type_annonceur"}
    }
  ],

  "axes": [
    {"orient": "bottom", "scale": "x"},
    {"orient": "left", "scale": "y"}
  ],

  "marks": [
    {
      "type": "group",
      "from": {
        "facet": {
          "name": "series",
          "data": "prix_m2_med_par_nb_pieces",
          "groupby": "type_annonceur"
        }
      },
      "marks": [
        {
          "type": "line",
          "from": {"data": "series"},
          "encode": {
            "enter": {
              "x": {"scale": "x", "field": "nb_pieces"},
              "x2": {"scale": "x", "value": 0},
              "y": {"scale": "y", "field": "prix_m2_median"},
              "stroke": {"scale": "color", "field": "type_annonceur"},
              "strokeWidth": {"value": 2}
            },
            "update": {
              "Ville": {"signal": "Ville"},
              "fillOpacity": {"value": 1}
            },
            "hover": {
              "fillOpacity": {"value": 0.5}
            }
          }
        }
      ]
    }
  ]
}