Does anyone know of a software or service that can define whether a location is inside or outside of city and county jurisdictions?

Our company is getting hit with huge tax audits because we did not collect sales tax in certain cities that impose a 1-2% tax rate as well as counties. I'd like to be able to imput an address, have it converted to GPS coordinates for accurate location and provide location information on whether a location is inside or outside of city and county jurisdictions so the correct rate can be calculated.

2 Answers 2


I do not know of a Commercial Service, but the US Census Tiger Dataset has a lot of City Boundary information that is current as of 2014. These are supplied as Shape Files which could be loaded into a PostGres/PostGIS database

You would need to implement a Reverse GeoCode Lookup (this is a link to Google's service) to obtain a Latitude/Longitude for the address.

It is then a relatively simple matter to run a PostGIS query to determine which polygons in the PostGres/PostGIS database that point lies within.

You would need to manage a relationship of those polygons and your business data; ie: what tax should be collected for that Polygon.

I see you tagged Geoserver on your question, this solution would not need Geoserver, but could be implemented in any one of the many programming languages available.


I did some development a couple of years ago for a company called Avalara that provides commercial services (built on MapDotNet) for obtaining just that sort of information about tax jurisdictions for a given location by address or by coordinates.

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