Google Maps Find Altitude

Quick Find :

[Map Height : Small - Medium - Large]

Description

A method of determining altitude (height) when a point is clicked on a map.

How To Use

1. Click on the map on a location where you wish to find the altitude
2. The altitude will be displayed in the message box below the map

How it Works

var mapDiv=document.getElementById('mapDiv');
var map;
function Gload()
{
mapDiv.innerHTML='Loading ...';
if(!GBrowserIsCompatible())
{
mapDiv.innerHTML='Sorry, your browser is not compatible with Google Maps.';
return;
}
map = new GMap2(document.getElementById("map"));
map.addControl(new GLargeMapControl());
map.addControl(new GMapTypeControl());
map.addControl(new GScaleControl());
map.setCenter(new GLatLng(0,0), 2);
map.setMapType(G_HYBRID_MAP);

GEvent.addListener(map, "click", function(overlay,point,overlaylatlng)
{
if(point)
{
mapDiv.innerHTML="Finding Altitude...";
map.addOverlay(createMarker(point));
findalt(point);
}
});
mapDiv.innerHTML="Ready";
}
function findalt(point)
{
var script = document.createElement("script");
document.body.appendChild(script);
var selectedWebService="gtopo30";
script.src = "http://ws.geonames.org/" + selectedWebService + "JSON?lat=" + point.lat() + "&lng=" + point.lng() + "&callback=loadJSON";
}
function loadJSON(result)
{
var filter = new Array();
filter[0] = "gtopo30";
var output=JSON.stringify(result,filter);
var output2=JSON.parse(output);
mapDiv.innerHTML =output2.gtopo30+"m";
}
function createMarker(point)
{
var marker=new GMarker(point);
return marker;
}
function ClearMap()
{
map.clearOverlays();
mapDiv.innerHTML="";
}

Relevant Links

http://www.geonames.org/

Further Uses and Ideas

• None at the current time

Version History

• Version 1 (28/09/2008)
• Version 1.1 (28/12/2008)
  • Added quick find option
• Version 1.2 (21/03/2009)
  • Enlarged output text at bottom of map
• Version 1.3 (04/012/2009) - You are here
  • Output now also displayed in feet

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