Postcode Lookup Tool

This repository contains a simple Python package for looking up UK postcodes to obtain their easting/northing coordinates and corresponding latitude/longitude values. The package reads data from CSV files based on the postcode prefix and uses this data to perform lookups efficiently.

Features

• Lookup eastings and northings for a given UK postcode.
• Convert the easting and northing coordinates to latitude and longitude.
• Efficient caching using functools.lru_cache to improve performance for repeated postcode prefix lookups.

Installation

You can install this package directly from PyPI using pip:

pip install uklookup

Usage

Command Line Usage

Once installed, you can use the package directly from the command line to look up the easting, northing, latitude, and longitude for a UK postcode:

python -m uklookup "SW1A 1AA"

Example output:

Postcode: SW1A 1AA
Easting: 530046, Northing: 179386
Latitude: 51.501009, Longitude: -0.141588

Programmatic Usage

You can also import the package and use it in your own Python scripts.

Example:

from uklookup import lookup_postcode_lat_long

postcode = "SW1A 1AA"
lat_long = lookup_postcode_lat_long(postcode)

if lat_long:
    lat, long = lat_long
    print(f"Latitude: {lat}, Longitude: {long}")
else:
    print("Postcode not found.")

Functions

lookup_postcode(postcode: str) -> Optional[Tuple[int, int]]

Looks up the easting and northing for a given UK postcode. Returns a tuple of integers (easting, northing) if found, or None if the postcode is not in the dataset.

lookup_postcode_lat_long(postcode: str) -> Optional[Tuple[float, float]]

Looks up the latitude and longitude for a given UK postcode. Returns a tuple of floats (latitude, longitude) if found, or None if the postcode is not in the dataset.

Dependencies

• numpy
• convertbng (for converting eastings/northings to latitudes/longitudes)

License

This project is licensed under the MIT License.

Acknowledgements

This project uses data from the Code-Point Open dataset provided by Ordnance Survey. The data is available under the Open Government Licence v3.0.

Other Projects

A much more comprehensive postcode lookup tool is available at postcodes.io. This project is a simple alternative for basic postcode lookups in an offline setting.