# Supply and update

The primary supply mechanism of AddressBase data is referred to as non-geographic chunks. This is a way of dividing up the data into chunks that are supplied in separate volumes, which have a fixed maximum number of records. The supply is not supplied with any reference to the geographic position of records.

Public Sector Geospatial Agreement (PSGA) customers can order Geographic chunks (5km tiles) as well as non-geographic chunks, although geographic chunks are not considered the main form of supply.

All customers are also able to take a complete supply (referred to as a Managed Great Britain Set: MGBS) or an Area of Interest (AOI) as a full supply or a COU supply.

## **Non-geographic chunks (unzipped)**

If you receive your data as non-geographic chunks, the filename will be constructed as follows:

*productName\_supply\_ccyy-mm-dd\_vvv.format* 

Where:

* **ProductName** is AddressBase.
* **supply** is defined as `FULL` or `COU`.
* **ccyy-mm-dd** is the date the file was generated.
* **vvv** is the volume number of the file.
* **format** is the format of the files received, for example, `csv` or `gml`. 

For example:

* `AddressBase_FULL_2013-05-28_001.gml` (GML full supply)
* `AddressBase_COU_2013-05-28_001.csv` (CSV COU supply)

## **Non-geographic chunks (zipped)**

If the data has been provided in a ZIP file, the filename will be constructed as follows:

*productName\_supply\_ccyy-mm-dd\_vvv\_format.zip* 

For example:

* `AddressBase_FULL_2013-05-28_001_gml.zip` (GML full supply zipped)

## **Geographic chunks (unzipped)**

If you receive your data as geographic chunks (PSGA customers only), the filename will be constructed as follows:

*productName\_supply\_ccyy-mm-dd\_ngxxyy.format* 

Where:

* **ProductName** is AddressBase.
* **supply** is defined as `FULL` or `COU`.
* **ccyy-mm-dd** is the date the file was generated.
* **ngxxyy** is the four-digit grid reference belonging to the 1km south-west corner of the 5km chunk.
* **format** is the format of the files received, for example, `csv` or `gml`. 

For example:

* `AddressBase_FULL_2013-05-28_NC4040.gml` (GML full supply)
* `AddressBase_COU_2013-05-28_NC4040.csv` (CSV COU supply)

### **Geographic chunks (zipped)**

If the data has been provided in a ZIP file, the filename will be constructed as follows:

*productName\_supply\_ccyy-mm-dd\_ngxxyy\_format.zip* 

For example:

* `AddressBase_COU_2013-05-28_NC4040_csv.zip` (CSV COU supply zipped)

## COU Supply

AddressBase is available as a full or COU supply.

A COU supply of data contains records or files that have changed between product refresh cycles. The primary benefit in supplying data in this way is that data volumes are smaller therefore reducing the amount of data that requires processing when compared to a full supply.

COU data enables a user to identify three types of change:

* Deletes (CHANGE\_TYPE ‘D’) are objects that have ceased to exist in your AOI since the last product refresh.
* Inserts (CHANGE\_TYPE ‘I’) are objects that have been newly inserted into your AOI since the last product refresh.
* Updates (CHANGE\_TYPE ‘U’) are objects that have been updated in your AOI since the last product refresh.

### Non-geographic chunked COU <a href="#id-4.1_non-geographic_chunked_cou" id="id-4.1_non-geographic_chunked_cou"></a>

A COU file for non-geographic chunked data can be identified by its naming convention. Any change record will be provided as a full record with the appropriate change type, as listed above.

### Geographic chunked COU (tile-based) <a href="#id-4.2_geographic_chunked_cou_-tile-based" id="id-4.2_geographic_chunked_cou_-tile-based"></a>

A geographic chunked COU is not supplied as per the non-geographic chunked COU outlined above. Its file naming convention can be found above. If a single record has changed within a specified 5km tile, the entire 5km tile containing all features will be supplied. This means the user will need to remove all features that previously existed in the provided tile(s) and insert the entire new tile(s) in its place.

### Archiving <a href="#id-4.3_archiving" id="id-4.3_archiving"></a>

When users are deleting, inserting or updating features, it is up to the user to consider their archiving requirements. If deleted records are important to your business requirements, you must take appropriate action to archive previous records.


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