saxman/code.gs

## code.gs
// The name of the spreadsheet from the browser location bar.
// Copy after 'key=' until before the next URL parameter beginning w/&
var SPREADSHEET_ID = 'YOUR_SPREADSHEET_ID';

// The name of the sheet, displayed in a tab at the bottom of the spreadsheet.
// Default is 'Sheet1' if it's the first sheet.
var SHEET_NAME = 'YOUR_SHEET_NAME';

function doGet(request) {
  var callback = request.parameters.jsonp;
  var range = SpreadsheetApp.openById(SPREADSHEET_ID).getSheetByName(SHEET_NAME).getDataRange();
  var json = callback + '(' + Utilities.jsonStringify(range.getValues()) + ')';

  return ContentService.createTextOutput(json).setMimeType(ContentService.MimeType.JSON);
}

// Testing to see if the jsonp parameter is being used properly.
function testDoGet() {
  var request = {parameters: {jsonp: 'callback'}};
  var results = doGet(request);
  Logger.log(results.getContent());
}

## data.tsv

          
            Tokyo
            35676000
            139.748689741861
            35.6839177113378

            
              New York
              19040000
              -74.0053780488293
              40.7381845017629

            
              Mexico City
              19028000
              -99.1360208861628
              19.4343637298345

            
              Mumbai
              18978000
              72.8293779578763
              19.0031122972043

            
              Sao Paulo
              18845000
              -46.6488782744749
              -23.5700291320421

            
              Delhi
              15926000
              77.2092899952401
              28.6631443881192

            
              Shanghai
              14987000
              121.403320470608
              31.2161528692896

            
              Kolkata
              14787000
              88.3026737620059
              22.4876238728558

            
              Dhaka
              12797394
              90.3849270256707
              23.7123779415253

            
              Buenos Aires
              12795000
              -58.4243794896826
              -34.6100658073734

## index.html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>My Awesome Map</title>

    <style>
      html, body {
        margin: 0;
        padding: 0;
        width: 100%;
        height: 100%;
      }

      #map_canvas {
        width: 100%;
        height: 100%;
      }
    </style>

    <script src="https://maps.google.com/maps/api/js?sensor=false"></script>

    <script>
      // The web service URL from Drive 'Deploy as web app' dialog.
      var DATA_SERVICE_URL = "<YOUR_WEB_SERVICE_URL>?jsonp=callback";

      var map;

      function initialize() {
        map = new google.maps.Map(document.getElementById('map_canvas'), {
          center: new google.maps.LatLng(0, 0),
          zoom: 2,
          maxZoom: 20,
          mapTypeId: google.maps.MapTypeId.ROADMAP
        });

        var scriptElement = document.createElement('script');
        scriptElement.src = DATA_SERVICE_URL;
        document.getElementsByTagName('head')[0].appendChild(scriptElement);
      }

      function callback(data) {
        for (var i = 0; i < data.length; i++) {
          var marker = new google.maps.Marker({
            position: new google.maps.LatLng(data[i][3], data[i][2]),
            map: map
          });
        }
      }
    </script>
  </head>

  <body onload="initialize()">
    <div id="map_canvas"></div>
  </body>
</html>
	// The name of the spreadsheet from the browser location bar.
	// Copy after 'key=' until before the next URL parameter beginning w/&
	var SPREADSHEET_ID = 'YOUR_SPREADSHEET_ID';

	// The name of the sheet, displayed in a tab at the bottom of the spreadsheet.
	// Default is 'Sheet1' if it's the first sheet.
	var SHEET_NAME = 'YOUR_SHEET_NAME';

	function doGet(request) {
	var callback = request.parameters.jsonp;
	var range = SpreadsheetApp.openById(SPREADSHEET_ID).getSheetByName(SHEET_NAME).getDataRange();
	var json = callback + '(' + Utilities.jsonStringify(range.getValues()) + ')';

	return ContentService.createTextOutput(json).setMimeType(ContentService.MimeType.JSON);
	}

	// Testing to see if the jsonp parameter is being used properly.
	function testDoGet() {
	var request = {parameters: {jsonp: 'callback'}};
	var results = doGet(request);
	Logger.log(results.getContent());
	}
Tokyo	35676000	139.748689741861	35.6839177113378
New York	19040000	-74.0053780488293	40.7381845017629
Mexico City	19028000	-99.1360208861628	19.4343637298345
Mumbai	18978000	72.8293779578763	19.0031122972043
Sao Paulo	18845000	-46.6488782744749	-23.5700291320421
Delhi	15926000	77.2092899952401	28.6631443881192
Shanghai	14987000	121.403320470608	31.2161528692896
Kolkata	14787000	88.3026737620059	22.4876238728558
Dhaka	12797394	90.3849270256707	23.7123779415253
Buenos Aires	12795000	-58.4243794896826	-34.6100658073734
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>My Awesome Map</title>

	<style>
	html, body {
	margin: 0;
	padding: 0;
	width: 100%;
	height: 100%;
	}

	#map_canvas {
	width: 100%;
	height: 100%;
	}
	</style>

	<script src="https://maps.google.com/maps/api/js?sensor=false"></script>

	<script>
	// The web service URL from Drive 'Deploy as web app' dialog.
	var DATA_SERVICE_URL = "<YOUR_WEB_SERVICE_URL>?jsonp=callback";

	var map;

	function initialize() {
	map = new google.maps.Map(document.getElementById('map_canvas'), {
	center: new google.maps.LatLng(0, 0),
	zoom: 2,
	maxZoom: 20,
	mapTypeId: google.maps.MapTypeId.ROADMAP
	});

	var scriptElement = document.createElement('script');
	scriptElement.src = DATA_SERVICE_URL;
	document.getElementsByTagName('head')[0].appendChild(scriptElement);
	}

	function callback(data) {
	for (var i = 0; i < data.length; i++) {
	var marker = new google.maps.Marker({
	position: new google.maps.LatLng(data[i][3], data[i][2]),
	map: map
	});
	}
	}
	</script>
	</head>

	<body onload="initialize()">
	<div id="map_canvas"></div>
	</body>
	</html>