title: D3js Map : GeometryCollection Vs FeaturesCollection
body: <p>I've been drawing maps for few weeks now but everytime i had that kind of geojson file (Featurecollection). Basicaly multiple arrays of coordinates for different neighborhoods of casablanca (in my example)</p>
  
  <blockquote>
    <p>{"type": "FeatureCollection","crs": { "type": "name", "properties": {
    "name": "urn:ogc:def:crs:OGC:1.3:CRS84" }     },  "features": [{
          "type": "Feature",      "properties": {             "name": "sid elkhader",
              "arrondissement": "Hay Hassani",            "prefecture": "Hay Hassani",
              "Population": 18930,            "area": 1616340.045         },      "geometry": {
              "type": "Polygon",          "coordinates": [
                  [
                      [-7.686476562432639, 33.559325447129368],
                      [-7.690429687499997, 33.557167523684669],
                      [-7.690712466572602, 33.55630146957499],
                      [-7.69193172454834, 33.557239049346535],
                      [-7.6959228515625, 33.56135167528992],
                      [-7.696309089660644, 33.561208630718284],
                      [-7.696545124053955, 33.561494719624619],
                      [-7.697145938873291, 33.561584122213503],
                      [-7.698111534118651, 33.562549664276048],
                      [-7.696180343627932, 33.56406947713436],
                      [-7.698715871374095, 33.566658445267336],
                      [-7.697645503668443, 33.567405785590324],
                      [-7.697098054802192, 33.567712878788591],
                      [-7.696259117371391, 33.568261506969215],
                      [-7.696011511349325, 33.5683181977139],
                      [-7.697387200000034, 33.570266599999982],
                      [-7.696740007740531, 33.570256969950947],
                      [-7.695561836061942, 33.570528261065235],
                      [-7.694268410063101, 33.570921223641093],
                      [-7.693596744041679, 33.571075056616195],
                      [-7.692447518598163, 33.571143296338079],
                      [-7.69142000156123, 33.571163408675481],
                      [-7.690155388704593, 33.57138033300906],
                      [-7.689247978305328, 33.571612665313971],
                      [-7.688806874513382, 33.571727285593433],
                      [-7.688311409275937, 33.571857958148009],
                      [-7.687409400000027, 33.572054400000049],
                      [-7.687391678068598, 33.572059961946792],
                      [-7.684979438782096, 33.568718150423749],
                      [-7.683219909667969, 33.565678661594823],
                      [-7.683406457011668, 33.563482296958043],
                      [-7.683829534164441, 33.562429900601146],
                      [-7.686476562432639, 33.559325447129368]
                  ]           ]       }   }, {        "type": "Feature",      "properties": {             "name": "nassim",           "arrondissement": "Hay Hassani",            "prefecture": "Hay
    Hassani",             "Population": 18898,            "area": 4776317.152         },
          "geometry": {           "type": "Polygon",          "coordinates": [
                  [
                      [-7.665259712372787, 33.530737914470194],
                      [-7.663579428308825, 33.5378162517151],
                      [-7.660416146883682, 33.53687582432655],
                      [-7.653830735645996, 33.533727400613216],
                      [-7.653876700000025, 33.5326443],
                      [-7.65348, 33.531745500000149],
                      [-7.653190299999866, 33.529947799999803],
                      [-7.652943599999785, 33.528677899999671],
                      [-7.653615699999913, 33.526604099999851],
                      [-7.653936200000107, 33.525365200000174],
                      [-7.654509399999957, 33.5241387],
                      [-7.655106500000205, 33.522667000000347],
                      [-7.656280299999967, 33.520306199999879],
                      [-7.656956199999512, 33.519349099999339],
                      [-7.658114900000093, 33.517926900000134],
                      [-7.658983900000114, 33.516343700000149],
                      [-7.659490200000375, 33.515535600000646],
                      [-7.6601104, 33.5145457],
                      [-7.660947299999948, 33.513347099999926],
                      [-7.662599500000061, 33.511602700000104],
                      [-7.664262500000047, 33.510654500000086],
                      [-7.666333199999984, 33.509563099999966],
                      [-7.668178499999983, 33.50827],
                      [-7.668900600000119, 33.507543800000242],
                      [-7.669823299999847, 33.506934599999816],
                      [-7.670733100000266, 33.507059900000414],
                      [-7.673713600000018, 33.50863970000001],
                      [-7.676073900000079, 33.509053],
                      [-7.68223779133892, 33.508502572767156],
                      [-7.684989189541704, 33.508844023847608],
                      [-7.683734893798827, 33.512559745083195],
                      [-7.675151824951172, 33.519357925734134],
                      [-7.674551010131836, 33.520717497758142],
                      [-7.671031951904296, 33.524796085610056],
                      [-7.668800354003906, 33.526441777122507],
                      [-7.668285369873048, 33.528516734826688],
                      [-7.665259712372787, 33.530737914470194]
                  ]           ]       }   } ....</p>
  </blockquote>
  
  <p>Now, since i'm exporting geojson files from openstreemap <a href="https://github.com/topojson/topojson/issues/37" rel="nofollow noreferrer">http://polygons.openstreetmap.fr/index.py</a> i'm having that type of geojson (GeometryCollection) for a specific town (no neighborhoods, only the form of a town)</p>
  
  <blockquote>
    <p>{"type":"GeometryCollection","geometries":[{"type":"MultiPolygon","coordinates":[[[[-5.9429266,35.745548300000003],[-5.9379208,35.743288800000002],[-5.9327023,35.7417388],[-5.9272307,35.741231999999997],[-5.9202848,35.741909499999998],[-5.9166306,35.746408000000002],[-5.9156028,35.7496942],[-5.9046272,35.760035999999999],[-5.9001726,35.762371000000002],[-5.8900896,35.7656931],[-5.8790518,35.756111199999999],[-5.8770798,35.7525902],[-5.8737711,35.745343900000002],[-5.872858,35.742017500000003],[-5.8727035,35.741004699999998],[-5.8699858,35.732553199999998],[-5.869492,35.731017299999998],[-5.8673423,35.728874099999999],[-5.8638447,35.7260068],[-5.8619479,35.7246934],[-5.8556436,35.720934100000001],[-5.8510603,35.719324399999998],[-5.8464426,35.716996799999997],[-5.8434943,35.714585599999999],[-5.8387091,35.711292700000001]
    ....</p>
  </blockquote>
  
  <p>Here are my questions :</p>
  
  <ol>
  <li>When i try to draw the map with the Geometrycollection geojson type, i'm having a huge square with a blank point, is it because i'm only having 1 single array of coordinates and not multiple like the 1st example ???</li>
  <li>How can i structure a new geojson file to use the coordinates of the Geomtrycollection into a FeatureCollection (since it works only with that type) ???</li>
  </ol>
  
  <p>I've been searching a lot <a href="https://github.com/topojson/topojson/issues/37" rel="nofollow noreferrer">Tip 1</a> and here <a href="https://stackoverflow.com/questions/27563382/how-to-load-geometrycollection-of-geojson-file-in-d3">Tip 2</a> and here <a href="https://gis.stackexchange.com/questions/165303/geojson-how-to-style-features-of-geometrycollection">Tip 3</a>
  but i couldn't find my answer</p>
  
  <p>Thank y'all for your help</p>