Simple Map w/ external GeoJSON, Promises, and jQuery Geo by maptastik

index.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>jQuery Geo-KY Map</title>
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <div id="map"></div>

  <script src="//code.jquery.com/jquery-2.2.4.min.js"></script>
  <script src="//code.jquerygeo.com/jquery.geo-1.0.0-rc1.min.js"></script>
  <script src="map.js"></script>
</body>
</html>

map.js

// request GeoJSON feature data
var counties = $.ajax({
   url: "kyCounties.geojson",
   dataType: "json",
   success: function (result){
     return result;
   },
   error: function (xhr) {
     alert(xhr.statusText)
   }
 });

 // once the county data is retrieved, we can start making a map!
$.when(counties).done(function(){
  // set up the map
  var map = $("#map").geomap({
    center: [-85.632935, 37.857507],
    zoom: 7,
    services: [{
      id: "toner",
      type: "tiled",
      src:"http://a.basemaps.cartocdn.com/light_all/{{:zoom}}/{{:tile.column}}/{{:tile.row}}.png"
    }]
  });

  // parse the responseText property from the feature data request as JSON
  counties = JSON.parse(counties.responseText);
  // add and style the feature data
  map.geomap("append", counties, {
    fill: "#2196F3",
    fillOpacity: 0.75,
    stroke: "#212121",
    strokeOpacity: 1,
    strokeWidth: 1
  });
});

style.css

body {
  margin: 0;
  padding: 0;
}
#map {
  position: absolute;
  top: 0;
  bottom: 0;
  width: 100%;
}