Choosing the best batch geocoding method for your data

Sloc Local’s batch geocoding feature allows you to generate geographic coordinates for hundreds or thousands of sites with just a few clicks. To ensure the best possible match for your data, Sloc offers two batch geocoding methods:

1. Geocoding by postcode

This method is ideal when:

• You want fast, consistent matches.

• You have a reliable postcode field for all sites.

How it works

Postcode-based geocoding uses the information from a single postcode column to assign coordinates to each site. It guarantees a 100% match rate as long as the postcode is valid and recognised in the database.

Things to be aware of

• Postcodes typically represent an area rather than a specific address. When geocoding by postcode, the coordinates returned will correspond to the central point of that postcode area. As a result, the accuracy of postcode-based geocoding depends both on the precision of the postcode itself and the size of the area it covers.

  Postcode sizes can vary significantly — both within a country and between countries. You can refer to our postcode precision by country for an overview of typical postcode accuracy in selected countries.

  

  Example: The blue lines in the image show the varying sizes of postcode areas in Portsmouth, UK. The central point of each postcode is marked by its corresponding label.

• It’s also important to note that multiple sites sharing the same postcode will geocode to the exact same set of coordinates - a situation more common in areas where postcodes cover larger geographic areas.

  

  Example: Four separate sites, all geocoded using the same postcode.

• As such, when postcode-level accuracy does not suffice - we recommend that you augment accuracy using Sloc Local's individual site geocoding methods.

2. Geocoding by address

This method is best when:

• You have detailed and well-formatted address fields.

• You want pinpoint accuracy for locations.

How it works

Address-based geocoding can accept a single address column or multiple columns (e.g. street, city, postcode). It attempts to find the closest matching location based on all available details.

Things to be aware of

• When using multiple address columns, try to order the fields in the same formatting order as the country you are searching in (e.g. house number, street, postcode, city, county).

• The system can return extremely accurate results when address formatting is consistent and comprehensive. However, it may miss or misinterpret even seemingly complete addresses depending on formatting and regional data quality. We are always improving its capabilities, but we highly recommend verifying the results of batch geocoding on address.

A combination of methods

You can also use a combination of methods if you’re working with different site types or have varying address completeness across your dataset:

First, geocode by your preferred method (e.g. geocode on address)

Subsequently, geocode the sites still missing coordinates via a fallback method (e.g. geocode on postcode, or geocode on address with different address fields)

Which method should I use?

The best method depends on your data quality and the analysis you need:

Pro tips

• Our geocoding methods built to handle minor formatting discrepancies. But you can edit your address columns directly in the table if you spot any glaring typos or missing data causing issues.

• You can always refine the accuracy of batch geocoding or complete any missing geocodes using Sloc Local's individual site geocoding methods.

• Improve accuracy by limiting result to a relevant country or countries to search within

Performance considerations

• Please note that batch geocoding can take a while to carry out for large datasets (e.g. thousands of rows), typically matching ~1,000 sites per minute.

• We cache recently used geocode searches, so re-running the same search will be much quicker if repeated.