SEOUL—Google Inc. on Tuesday revised its Google Maps application to add information for North Korea, which has been blank since it started providing maps online and for mobile devices eight years ago, and included outlines of some of the country's notorious, city-sized prison camps.
The information for the North Korea map was added by people who are interested in the country under a Google development program called Map Maker, a collaborative effort that has become known as crowdsourcing.
The release came just three weeks after Google's executive chairman, Eric Schmidt, visited North Korea in a highly-publicized trip with former American diplomat Bill Richardson. Mr. Schmidt encouraged officials he met in North Korea to make the Internet available to its citizens and end its attempts to restrict information.
A company spokesman said there was no connection between the visit and the new map.
"This data has been in Map Maker for a while now, but it commonly takes the Map Maker community a few years to generate enough high quality data to make something that works in Google Maps," the spokesman said.
He added that Google has relied on "citizen cartographers" to help it create maps in 150 countries and have made huge contributions in places where governments have done little mapping—such as Afghanistan.
In a blog post, Google said that it determined the work on North Korea had reached a level of detail and credibility where it could be incorporated into the Google Map product.
Hwang Min-woo, a 28-year-old South Korean who contributed to the North Korea map, said he began working on it after trying to use Google Maps on a trip to Laos four years ago and finding it inadequate.
"I thought if I could fill in information on North Korea, it might be useful in an emergency or a tragedy if Google can provide a map for aid agencies," Mr. Hwang said.
He said he used information from maps of the North on a website run by the South Korean government.
The new map of North Korea has far less information than files available through other private efforts using a different Google product, a satellite image program called Google Earth.
Curtis Melvin, who has spent years leading a crowdsourcing effort to map North Korea using Google Earth, said he was surprised to learn of the separate work for Google Maps.
"It's not even a fraction of what I've already published," he said.
Mr. Melvin, who also publishes a website called North Korean Economy Watch, recently collaborated with 38 North, a North Korea website operated by the Johns Hopkins School of Advanced International Studies, on a digital atlas of North Korea. He has relied on information provided by people who have visited North Korea or former citizens who defected from it.
The Google spokesman said the company has noticed that the community of people interested in mapping tends to be separate from those who concentrate on satellite images.
Jayanth Mysore, senior product manager, wrote in a blog post that the North Korea map is "not perfect" and added Google encourages people "to continue helping us improve the quality of these maps."
One of the striking features of North Korea on Google Maps is a highlighting of the areas where the country operates gulag-like work camps, believed to be some of the largest and most inhumane prisons in the world. Brown shading stands out against the light beige background, instantly imparting to a user of Google Maps the enormous size of the prisons.
However, only a few of the prisons that Mr. Melvin and other observers have identified are shown on the Google map.
With the help of "citizen cartographers," Google Maps has filled in some of North Korea's streets and prison camps. The WSJ's Evan Ramstad gives a preview of some places the world's most reclusive nation would rather keep a secret.