Wednesday, August 17, 2016

Google Maps Distance Matrix may not be what you’re after

For many years I’ve been using the Google Maps APIs on my website. It’s been fun to use and until recently the licensing has been very unrestrictive. If an API returned a response saying you’d gone over the query limit, just wait for a second or so, try again and generally it would work. So with some use of setTimeout, it was possible to build reasonably scalable apps that cost nothing.

It’s looking like those days are coming to an end. The various APIs are starting to introduce hard limits on their usage. Once you’re over the limit, that’s it until the counter resets at the start of the next day. I first hit this with my use of the Directions API in my Driving Distances page. I can’t say I’m too happy with the way it was introduced, the Google API Console had given no previous indication of my usage of the API but on the same day as they started displaying the usage report, the hard limit was also introduced. Since my site was way over the limit, that page fell over almost immediately.

So I had a Baldrick cunning plan. I’d swap out the Directions API for the Distance Matrix API. This is exactly the kind of application this API was designed for. Unfortunately I failed to read the usage limits correctly and after I uploaded the new code, the page fell over in a heap again after a few hours. It turns out the usage limits apply to the elements passed to the Distance Matrix API, not the number of requests. So a 10 by 10 matrix counts as 100 towards the free 2,500 limit, not 1 as I had assumed. Given that this API provides less information and has fewer options than the Directions API but has the exact same usage limits, this is rather disappointing!

I am trying to figure out the best way forward now. I could start to pay for extra requests, but since a 100 by 100 matrix would cost $5, the costs could mount up quickly. I can put a maximum daily cost on the account so I don’t have to pay enormous amounts if someone overuses the page, but this could lead to the page becoming unavailable again.

I suspect the outcome will be me removing the page, or at least no longer linking to it from the rest of the site. I make a tidy sum from Google AdSense advertising on the site, but I fear this may just be the start, as more and more APIs start to introduce a hard limit and I don’t particularly want to pay that money back to Google every month to pay for their APIs. It was fun whilst it lasted I guess!

1 comment:

Anonymous said...

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