Google Maps Developer Overview

 

What are the Google Maps APIs?

The Google Maps APIs give developers several ways of embedding Google Maps into web pages, and allows for either simple use or extensive customization. There are now several API offerings:

• Google Maps Javascript API
• Google Maps API for Flash
• Google Static Maps API

Depending on your needs, you may find yourself using one or a combination of these APIs.

If you operate an enterprise or commercial website, you may also be interested in Google Maps API for Business.

Google Maps has a wide array of APIs that let you embed the robust functionality and everyday usefulness of Google Maps into your own website and applications, and overlay your own data on top of them.

What you can do with the Google Maps APIs

Maps JavaScript API Embed an interactive Google Map in your webpage using JavaScript.

Google Earth API Take your visitors anywhere on the Earth without leaving your web page.

Maps Image APIs Embed a Google Maps image or Street View panorama in your web page without requiring JavaScript.
Static Maps - Street ViewWeb Services Use URL requests to access geocoding, directions, elevation, and place information.

Maps for Business Google Maps API for Business provides Enterprise-ready application support for your mapping needs.

Places API Access information about establishments, geographic locations, or prominent points of interest.

 Maps applications on mobile devices

The Google Maps JavaScript API V3 has been developed to cater to mobile devices, and is suitable for browser applications targeted at both the desktop and devices that include a web browser with a full JavaScript implementation, such as the Apple iPhone.

For applications targeted at devices not suitable for using the JavaScript API, the Static Maps API delivers map images in GIF, JPG, and PNG formats, including markers and polylines. Note that use of the Static Maps API outside of browser based applications requires that the map image be linked to Google Maps.

To incorporate maps in an Android application, use the Android Maps External Library.

To incorporate Maps in a native iPhone application, use the Apple iPhone Map Kit framework.

The Google Maps JavaScript API supports the following web browsers:

Google Maps JavaScript API V3:

·         IE 7.0+ (Windows) *

·         Firefox 3.0+ (Windows, Mac OS X, Linux)

·         Safari 4+ (Mac OS X, iOS)

·         Chrome (Windows, Mac OS X, Linux)

·         Android

·         BlackBerry 6

·         Dolfin 2.0+ (Samsung Bada)

When using the JavaScript Maps API, the following information is sent to Google:

• Map size and location for retrieving map tiles and copyrights
• Addresses for geocoding
• Direction and Elevation requests
• Locations around which to search for Places
• KML when using KmlLayer (V3) or GGeoXml (V2)

The Google Maps APIs Can accessed over SSL (HTTPS)

The Google Maps JavaScript API V3, Google Static Maps API, and Google Maps API Web Services can be accessed over secure (HTTPS) connections by developers using either the free version of these APIs or Google Maps API for Business. Please see the documentation for the API concerned for information on how to access the API over SSL.

The Google Maps JavaScript API V2 and Google Maps API for Flash can be accessed over a secure (HTTPS) connection by Google Maps API for Business customers only. If these Maps APIs are used with a free Maps API key on a secure site, the browser may warn the user about non-secure objects on the screen.

Google Maps JavaScript API v3

The Google Maps Javascript API lets you embed Google Maps in your own web pages. Version 3 of this API is especially designed to be faster and more applicable to mobile devices, as well as traditional desktop browser applications.

The API provides a number of utilities for manipulating maps (just like on the http://maps.google.com web page) and adding content to the map through a variety of services, allowing you to create robust maps applications on your website.

The JavaScript Maps API V3 is a free service, available for any web site that is free to consumers. Please see the terms of use for more information.

Basic Map Types

There are many types of maps available within the Google Maps API. In addition to the familiar "painted" road map tiles, the Google Maps API also supports other maps types.

The following map types are available in the Google Maps API:

·         MapTypeId.ROADMAP displays the default road map view

·         MapTypeId.SATELLITE displays Google Earth satellite images

·         MapTypeId.HYBRID displays a mixture of normal and satellite views

·         MapTypeId.TERRAIN displays a physical map based on terrain information.

You modify the map type in use by the Map by setting its mapTypeId property, either within the constructor via setting its Map options object, or by calling the map'ssetMapTypeId() method.

Layers Overview

Layers are objects on the map that consist of one or more separate items, but are manipulated as a single unit. Layers generally reflect collections of objects that you add on top of the map to designate a common association. The Maps API manages the presentation of objects within layers by rendering their constituent items into one object (typically a tile overlay) and displaying them as the map's viewport changes. Layers may also alter the presentation layer of the map itself, slightly altering the base tiles in a fashion consistent with the layer. Note that most layers, by design, may not be accessed via their individual objects, but may only be manipulated as a unit.

To add a layer to a map, you only need to call setMap(), passing it the map object on which to display the layer. Similarly, to hide a layer, call setMap(), passing null.

The Maps API has several types of layers:

·         KmlLayer objects render KML and GeoRSS elements into a Maps API V3 tile overlay.

·         HeatmapLayer objects renders geographic data using a Heatmap visualization.

·         FusionTablesLayer objects render data contained in Google Fusion Tables.

·         The TrafficLayer object renders a layer depicting traffic conditions and overlays representing traffic.

·         The TransitLayer object displays the public transport network of your city on the map.

·         The WeatherLayer and CloudLayer objects allow you to add weather forecasts and cloud imagery to your map.

·         The BicyclingLayer object renders a layer of bike paths and/or bicycle-specific overlays into a common layer. This layer is returned by default within theDirectionsRenderer when requesting directions of travel mode BICYCLING.

·         The PanoramioLayer object adds photos from Panoramio as a layer.

·         The DemographicsLayer object renders United States demographic information as a layer, and is available to Google Maps API for Business customers only. It is contained within the visualization library.

These layers are described below. The Demographics layer is documented in the Demographics Layer chapter of the Google Maps API for Business documentation.

Controls Overview

The maps displayed through the Google Maps API contain UI elements to allow user interaction with the map. These elements are known as controls and you can include variations of these controls in your Google Maps API application. Alternatively, you can do nothing and let the Google Maps API handle all control behavior.

The Maps API comes with a handful of built-in controls you can use in your maps:

·         The Zoom control displays a slider (for large maps) or small "+/-" buttons (for small maps) to control the zoom level of the map. This control appears by default in the top left corner of the map on non-touch devices or in the bottom left corner on touch devices.

·         The Pan control displays buttons for panning the map. This control appears by default in the top left corner of the map on non-touch devices. The Pan control also allows you to rotate 45° imagery, if available.

·         The Scale control displays a map scale element. This control is not enabled by default.

·         The MapType control lets the user toggle between map types (such as ROADMAP and SATELLITE). This control appears by default in the top right corner of the map.

·         The Street View control contains a Pegman icon which can be dragged onto the map to enable Street View. This control appears by default in the top left corner of the map.

·         The Rotate control contains a small circular icon which allows you to rotate maps containing oblique imagery. This control appears by default in the top left corner of the map. (See 45° Imagery for more information.)

·         The Overview Map control displays a thumbnail overview map reflecting the current map viewport within a wider area. This control appears by default in the bottom right corner of the map, and is by default shown in its collapsed state.

Note: the previously existing Navigation control has been deprecated and divided into separate Zoom and Pan controls.

You don't access or modify these map controls directly. Instead, you modify the map's MapOptions fields which affect the visibility and presentation of controls. You can adjust control presentation upon instantiating your map (with appropriate MapOptions) or modify a map dynamically by calling setOptions() to change the map's options.

Services

Directions Service

You can calculate directions (using a variety of methods of transportation) by using the DirectionsService object. This object communicates with the Google Maps API Directions Service which receives direction requests and returns computed results. You may either handle these directions results yourself or use the DirectionsRendererobject to render these results.

Directions may specify origins and destinations either as text strings (e.g. "Chicago, IL" or "Darwin, NSW, Australia") or as LatLng values. The Directions service can return multi-part directions using a series of waypoints. Directions are displayed as a polyline drawing the route on a map, or additionally as a series of textual description within a 

element (e.g. "Turn right onto the Williamsburg Bridge ramp").

Distance Matrix Service

Google's Distance Matrix service computes travel distance and journey duration between multiple origins and destinations using a given mode of travel.

This service does not return detailed route information. Route information, including polylines and textual directions, can be obtained by passing the desired single origin and destination to the Directions Service.

Elevation Service

The Elevation service provides elevation data for locations on the surface of the earth, including depth locations on the ocean floor (which return negative values). In those cases where Google does not possess exact elevation measurements at the precise location you request, the service will interpolate and return an averaged value using the four nearest locations.

The ElevationService object provides you with a simple interface to query locations on the earth for elevation data. Additionally, you may request sampled elevation data along paths, allowing you to calculate the equidistant elevation changes along routes. The ElevationService object communicates with the Google Maps API Elevation Service which receives elevation requests and returns elevation data.

Note that these requests are rate-limited to discourage abuse of the service. If instead you wish to calculate elevations for static, known locations, see the Elevation Web Servicedocumentation.

With the Elevation service, you can develop hiking and biking applications, mobile positioning applications, or low resolution surveying applications.

Geocoding Service

Geocoding is the process of converting addresses (like "1600 Amphitheatre Parkway, Mountain View, CA") into geographic coordinates (like latitude 37.423021 and longitude -122.083739), which you can use to place markers or position the map.

The Google Maps API provides a geocoder class for geocoding addresses dynamically from user input. These requests are rate-limited to discourage abuse of the service. If instead, you wish to geocode static, known addresses, see the Geocoding web service documentation.

Maximum Zoom Imagery Service

The Google Maps API provides map tiles at various zoom levels for map type imagery. Most roadmap imagery is available from zoom levels 0 to 18, for example. Satellite imagery varies more widely as this imagery is not generated, but directly photographed.

Because satellite imagery is not always available at high zoom levels for remote locations — sparsely populated areas or open ocean areas — you may want to know the highest zoom level for imagery at a given location beforehand. The MaxZoomService object provides a simple interface for discovering the maximum zoom level at a given location for which Google Maps has satellite imagery.

Street View Service

Google Street View provides panoramic 360 degree views from designated roads throughout its coverage area. Street View's API coverage is the same as that for the Google Maps application (http://maps.google.com/). The list of currently supported cities for Street View is available at the Google Maps Help Center.

The Google Maps Javascript API provides a Street View service for obtaining and manipulating the imagery used in Google Maps Street View. Unlike in the V2 API, the Street View service in the Maps Javascript API V3 is supported natively within the browser.

Libraries

The JavaScript code for the Maps API is loaded via a bootstrap URL of the form http://maps.googleapis.com/maps/api/js. This bootstrap request loads all of the main Javascript objects and symbols for use in the Maps API. Some Maps API features are also available in self-contained libraries which are not loaded unless you specifically request them. Breaking up supplemental components into libraries allows the main API to load (and parse) quickly; you only incur the additional overhead of loading and parsing libraries if you need them.

You specify additional libraries to load within the bootstrap request by specifying a libraries parameter, passing that parameter the name of the library or libraries. Multiple libraries may be specified as a comma-separated list. Once loaded, libraries are accessed via the google.maps.libraryName namespace.

The following libraries are currently available:

·         adsense allows your Maps API application to include context-sensitive text ads, allowing you to share in ad revenue for ads shown to your users. Consult the AdSense library documentation for more information.

·         drawing provides a graphical interface for users to draw polygons, rectangles, polylines, circles, and markers on the map. Consult the Drawing library documentation for more information.

·         geometry includes utility functions for calculating scalar geometric values (such as distance and area) on the the surface of the earth. Consult the Geometry library documentation for more information.

·         panoramio contains functionality for adding Panoramio photo layers to your Maps API application. Consult the Panoramio Layers documentation for more information.

·         places enables your application to search for Places such as establishments, geographic locations, or prominent points of interest, within a defined area. Please read thePlaces library documentation for more information.

·         visualization provides visual representations of heatmap data, and demographic information for the United States. For more information on heatmaps, see the Heatmap Documentation. For more information on the Demographics Layer, consult the Demographics Layer documentation in the Maps for Business guide.

·         weather contains functionality for adding weather forecasts and cloud imagery to your map. Consult the Weather Layer documentation for more information.