A new geologic map of Alaska is providing details about the location of mineral deposits statewide. Creators of the map said the data collected for the project has spanned over a century and took 20 years to piece together.

In a statement, the US Geological Survey said the purpose of the map is provide some help in locating main areas for ‘resource extraction, conservation, natural hazards and recreation’.

Research geologist Rick Wilson pointed out on the map, “Oil and gas occur in sedimentary rocks. These red ones here are all igneous rocks. Don’t waste your time looking for oil and gas there. A geologic map like this, it helps frame what you’re going to do”.

The map project started in 1998, and Wilson has worked along with a group of nearly a dozen scientists to complete the map.

National Park Service Director Jonathan B. Jarvis said in a statement that the data present in this digital map is going to be priceless. He called it a great resource, saying it will mainly enhance the capacity for science-informed decision making for cultural and natural resources, interpretive programs, and safety of visitors.

According to the USG, the map is the state’s first entirely digital geologic map, but the data collected for the map dates back to 1908, the time before scientists were aware of tectonic plates’ existence.

Wilson explained that there were some cases in which he consulted the original field notes of geologists that were mapped in the 1950s. While in others, he used Google Earth, satellite pictures and air images.

You can see the map online as it is present there with a detail that explains the kinds of rock formations, their ages and their location in the state. The map’s simpler version is also available for print.