Can you copyright a postal code? Canada Post thinks so.

The Crown corporation is suing a geocoding website for providing a free online database of Canadian postal codes, which it says infringes on its copyright.

But Geolytica, which runs GeoCoder.ca, says it built its collection of postal codes without any help from Canada Post's official database.

"This brings us here. Having to face a Crown corporation with deep pockets in Federal Court, over something we have created but which they believe otherwise," Geolytica founder Ervin Ruci wrote on the site's blog. "Fighting for principle is expensive, and we will do it."

Canada Post charges companies approximately $5,500 a year for the same information. The statement of claim filed by Canada Post says it's losing potential clients and revenue.

Canada Post spokeswoman Anick Losier wouldn't comment on the specifics of the case, but said the mail company depends on the revenue it gets from its database to recoup the costs of keeping it up to date.

"We are not a federal department. We are a self-sustaining Crown corporation that relies on the revenues from the sale of its products and services," she said.

"We deliver to 32 million Canadians every day. Each year, we create more than 200,000 new addresses, and countless others are changed or removed from the database. We also process 1.2 million change of address requests annually for Canadians who are moving from one residence to another

"As you can imagine, we invest a significant amount of time, effort and money to maintain our address data, and ensure that it is clean and accurate. Only Canada Post has the breadth of network required to collect and update this information on a daily basis."

Geolytica disagrees and says it used crowdsourcing to build its own databse, which means the information was generated by the site's own users and staff, not through Canada Post.

"When you make a query to Geocoder containing, for example, this information '1435 Prince of Wales, Ottawa, ON K2C 1N5,' we then extract the postal code 'K2C 1N5' and insert it into the database that you may download for free on this website," Ruci explained.

In its statement of defence, Geolytica also argues that postal codes are public data, not subject to copyright law.

"Canadians regularly and frequently write their postal codes on letters in order to indicate their factual locations. Canadians also frequently enter their full street address, including their postal codes, into online forms — all in a similar manner to the way users enter their full street address at geocoder.ca. These activities constitute no infringement of copyright," the statement reads.

On his blog, Canadian Internet and e-commerce expert Michael Geist said the lawsuit makes for "a fascinating case study on generating crowdsourced information."

"The case could certainly generate some notable intervenors. For marketers that have independently developed and marketed their own databases that include postal code information, they could face similar copyright claims by Canada Post and may need to support GeoCoder," he said.

"Given the government's emphasis on open data, the federal government may have something to say about Canada Post's efforts to restrict public compilation and distribution of postal code information."

Geist is on the board for the Canadian Internet Policy and Public Interest Clinic, which is representing Geolytica against Canada Post.

Geocoding turns street addresses into geographic co-ordinates, usually latitude and longitude, so they can be mapped. Social media services routinely use geocoding services to build maps or let people sign into locations on their phones.