如何正确添加图层控件？

Question

I seem to be having quite the issue adding a layer control menu to my page. I thought I had the code correct but every time I try to add it, it doesn't show. What am I doing wrong?

L.geoJSON(cities).addTo(map);

  ```code```

  var baseMaps = {
      "States": statesData
  };

  var overlayMaps = {
      "cities": cities
  };

  L.control.layers(baseMaps, overlayMaps).addTo(map);

Answer 1

You have to create a Layergroup / GeoJsonlayer to add them to the controler. You can not add the plain geojson Object to the controler.

var statesDataLayer = L.geoJSON(statesData); // Don't know if this is also geojson?
var citiesLayer = L.geoJSON(cities);

var baseMaps = {
      "States": statesDataLayer // Don't know if this is also geojson?
  };

  var overlayMaps = {
      "cities": citiesLayer
  };

  L.control.layers(baseMaps, overlayMaps).addTo(map);