> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-getting-started-guide.md).
# Code-Point Open Getting Started Guide
Code-Point Open locates over 1.7 million postcode units for Great Britain, each having a notional geographical location. Postcodes are an alphanumeric abbreviated form of an address. Postcode units are unique references and identify an average of 15 addresses. In some cases, where an address receives a substantial amount of mail, a postcode will apply to only one address and is defined as a large-user postcode. The maximum number of addresses in a postcode is 100.
Code-Point Open provides geographical locations for postcodes in Great Britain.
This getting started guide focusses on using the product in comma-separated values (CSV) format.
For general guidance on using the product in GeoPackage format, please see the [Getting started with GeoPackage guide](/os-downloads/resources/product-resources/getting-started-with-geopackage-and-vector-tiles-guides/getting-started-with-geopackage.md).
## Index
This getting started guide includes the following sections:
* [Requirements for using the data](/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-getting-started-guide/requirements-for-using-the-data.md)
* [CSV file processing](/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-getting-started-guide/csv-file-processing.md)
* [Data measures](/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-getting-started-guide/data-measures.md)
* [Loading the data into a GIS](/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-getting-started-guide/loading-the-data-into-a-gis.md)
* [Glossary](/os-downloads/products/areas-and-zones-portfolio/code-point-open/code-point-open-getting-started-guide/glossary.md)
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