Why does it slow down after a few hundred addresses?
The site uses Google Maps for geocoding. Their service has a limit on the number of requests it will process. I try to mitigate this by increasing the time between requests but this means geocoding gets slower and slower. There is a workaround that seems to alleviate the issue. Process addresses in batches of a few hundred and refresh the page between each batch. Note, if you're geocoding UK postcodes you shouldn't experience the slowdown since that uses my own database.
What is the meaning of the result quality?
Addresses geocoded with Google Maps provide the following result quality information.
- Rooftop indicates that the returned result is a precise geocode for which we have location information accurate down to street address precision. (most accurate)
- Range interpolated indicates that the returned result reflects an approximation (usually on a road) interpolated between two precise points (such as intersections). Interpolated results are generally returned when rooftop geocodes are unavailable for a street address.
- Geometric centre indicates that the returned result is the geometric center of a result such as a polyline (for example, a street) or polygon (region).
- Approximate indicates that the returned result is approximate. (least accurate)
Press 'Get started'
Choose Routes and Places when selecting products during the setup process
Then create a project
Then enable billing. Google now require billing to be enabled on your account, so beware of how much you'll be charged.
Google should then create an API key for you. That is what you need to enter in the field above
You should see a button saying 'Secure credentials'. Click this
Under 'Application restrictions', select 'HTTP referrers (websites)'
In the field that appears, type https://www.doogal.co.uk
and press 'Save'
Once that's done, you should be able to use your API key above
If you already have an API key, ensure the following APIs are enabled in your project
- Google Maps Geocoding
- Google Maps Directions
- Google Maps Distance Matrix