Why isn't this an instance of map of google.maps.Map? InvalidValueError: setMap: not an instance of Map;
The map variable that is an instance of a google.maps.Map is local to the initialize function. The map variable in the createMarker function is undefined. One option: define the variable in the global scope:
var map;
then just initialize it in the initialize function:
function initialize(){
var mapProp = {
center: new google.maps.LatLng(38, -78),
zoom: 10,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById('map'), mapProp);
};
proof of concept fiddle
code snippet:
var map;
function initialize() {
var mapProp = {
center: new google.maps.LatLng(38, -78),
zoom: 6,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById('map'), mapProp);
};
$(document).ready(function() {
var url = 'https://opendata.howardcountymd.gov/resource/96q9-qbh7.json';
initialize();
$.getJSON(url, function(data) {
$.each(data, function(i, field) {
$('#list').append("<li>" + data[i].location.longitude + " & " + data[i].location.latitude + "</li>");
createMarker(data);
function createMarker(data) {
var marker = new google.maps.Marker({
position: new google.maps.LatLng(data[i].location.latitude, data[i].location.longitude),
map: map,
title: field.crossroad
});
};
});
});
});#map {
height: 300px;
width: 600px;
border: 1px solid black;
margin: 0 auto;
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<h1 style="text-align: center;">Hello World</h1>
<div id="map"></div>
<ul id="list"></ul>Another option would be to return the map from the initialize function