LocationByZip

This library provides a small set of methods to work with U.S. ZIP Codes. With it, you can:

• Get locations that fall within a given radius (in miles) of a certain ZIP Code
• Get a City/State by ZIP Code
• Get a collection of one or more ZIP Codes by City/State
• Determine the distance (in miles) between two ZIP Codes

This project uses the geonames US Postal Code file under the Creative Commons Attribution 3.0 License.

Usage

In DemoConsoleApp, you'll see a .NET Core Generic Host set up to inject LocationService and SqlLocationRepository. You can use a similar setup in, e.g., an ASP.NET Core MVC application, although with a web application, you'd likely want to add them as scoped services.

services.AddTransient<LocationService, LocationService>();
services.AddTransient<ILocationRepository, SqlLocationRepository>();

You can then get an injected instance of LocationService.

To find all Locations within a given radius:

// IReadOnlyCollection<LocationInRadius>
var locationsInRadius = locationSvc.GetLocationsInRadius("93401", 10.0);

To look up a Location by ZIP Code:

// Location
var location = locationSvc.GetByZipCode("93275");

To look up a collection of Locations by City/State:

// IReadOnlyCollection<Location>
var locations = locationSvc.GetByCityState("Tulare", "CA");

To find the distance (currently in miles) between two ZIP Codes:

// double
var distanceInMiles = locationSvc.GetDistanceBetweenLocations("93401", "93446");

Creating the ZipCodes table

In the data folder, you'll find a CSV dump of US Postal Codes from 2020-02-26. Before generating the CSV, I removed the following two duplicates so that I could use Zip5 as the primary key:

Zip5 = '96860' AND PlaceName = 'FPO AA'
Zip5 = '96863' AND PlaceName = 'FPO AA'

Import the CSV into the database of your choice. This code uses Dapper to access a table named ZipCodes in a recent version of SQL Server .

You can find and edit the SQL in SqlLocationRepository.cs in the LocationByZip project.

The connection string is in appsettings.json in the LocationByZip.DemoConsoleApp project.

History

This is a code refresh of an article I wrote at The Code Project: ZIP Code Utility

• 2020-02-28: 4.0.0: Converted to .NET Core 3.1.
• 2013-12-19: Converted repo from hg to git. Hosted on GitHub.
• 2010-10-13: 3.0.0: Code modernization.
• 2005-01-02: Initial release on CodeProject.