Google Maps: from XML with Marker Clustering

January 2, 2018

#Google Maps #HTML5 Geolocation #JavaScript #jQuery #Marker Clustering #PHP #Shortcode API #WordPress #XML

 

This is something I was working on recently. We wanted to use Google Maps to show the location of the client’s many distributors and agents. And we wanted to implement marker clustering. You can use the MarkerClusterer library in combination with the Google Maps JavaScript API to combine markers of close proximity into clusters, and simplify the display of markers on the map. Zooming in you begin to see the individual markers on the map. Zooming out of the map consolidates the markers into clusters again.

I have defined the markers as XML elements with properties defined as attributes. Apart from latitude and longitude – the other properties define how I have chosen to implement the Info Windows – what a user sees when they click on a marker. In this example simply the business name, address and telephone number. But an Info Window can potentially provide much more detailed or layered information. Obviously in a real implementation of this example the name and address info would be different for each marker:

... <marker name="Business Name" address="Street Address Line 1, Street Addresss Line 2, City, Country, Code" tel="+XX 123 456 7890" lat="-36.7624557" lng="144.2874504" /><marker name="Business Name" address="Street Address Line 1, Street Addresss Line 2, City, Country, Code" tel="+XX 123 456 7890" lat="51.555386" lng="5.082930000000033" /><marker name="Business Name" address="Street Address Line 1, Street Addresss Line 2, City, Country, Code" tel="+XX 123 456 7890" lat="51.2164861" lng="4.4046062" /> ...

I am using the browser’s HTML5 Geolocation feature to attempt to locate the user on the map. That’s going to be confusing if your corporate network is routed through another jurisdiction. The user will be asked to allow the site to use their position. NB: Browsers including Chrome no longer support obtaining the user’s location using the HTML5 Geolocation API from pages delivered by non-secure connections. This means that the page making the Geolocation API call must be served from a secure context – eg HTTPS.

In this example I have implemented the map using the WordPress Shortcode API. We can simply add [insertSulbyMap] to the page or post where we want it. But it could equally be contained as a plugin or coded into a PHP template (which is how I did it in the version we built for the client).

The takeaway from this, for me, was that it was simple to code my own implementation using the Google documentation. Better than being an additional third party dependency by using a commercial plugin. Google already make it easy.



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