Federal and state governments are a trove of information. Now a lot of it is just an app away.

Joel Schectman, The Wall Street Journal, March 8, 2013

Most government data have been available to the public for decades. But trying to find information quickly and in a useful format has been another story altogether.

All that is starting to change. A growing open-government movement has pushed successfully for state and federal data to be made more readily available online, in user-friendly formats. And the federal government has begun to release its data in a digital format that allows software engineers to more easily use it to develop interactive applications. App developers are now mixing and matching government data to help consumers, businesses and researchers harvest new insights.

Here's a closer look at some of these apps and websites.

Labor and Health Violations

DATA: Records of labor-law and health-and-safety violations for hotels, restaurants and shops
SOURCES:U.S. Labor Department; Occupational Safety and Health Administration
DESCRIPTION: The Eat Shop Sleep app by Rachel Moore maps health and labor-law violations by restaurants, hotels and shops, and combines that information with Yelp reviews. Now you can find out that the hamburger joint down the street owes employees $5,653 in back wages—but the sweet-potato fries are supposed to be divine.

Salaries

DATA: Average salaries for hundreds of jobs listed by state
SOURCE: U.S. Bureau of Labor Statistics
DESCRIPTION: Aequitas, an app from Fuzion Applications Inc., gathers salary data for more than 800 occupations from all around the U.S. Job seekers can see the range of salaries in any area and find out what they might command in, say, Nevada versus Illinois.

Business-Owner Addresses

DATA: Addresses of business-license holders
SOURCES: City authorities
DESCRIPTION: The Your Mapper app from Metro Mapper LLC shows information for business-license holders in Chicago; Portland, Ore.; and Louisville, Ky., on city maps. Salespeople can use it to target potential customers.

Hospital Records

DATA: Hospital safety records and quality indicators; patient surveys
SOURCE:U.S. Centers for Medicare and Medicaid Services
DESCRIPTION: Hospital Quality, an app from MicroStrategy Inc., combines hospital safety and quality scores with patient-satisfaction scores gathered by CMS and uses the data to rank hospitals.

Flu Incidence

DATA: Weekly state influenza levels; crowdsourced reports
SOURCES:U.S. Centers for Disease Control and Prevention; Foursquare

DESCRIPTION: The Flusquare app from Floodlight Software LLC updates users on flu levels in their states and asks them to indicate when they may be sick.
If a user who also has downloaded the Foursquare app indicates enough symptoms to suggest he has the flu, the app then pulls his recent location data from Foursquare to find out where he visited when he was contagious. The app then warns other Flusquare users who were in his vicinity at that time to watch for symptoms.

Energy Prices

DATA: Consumption and price information for electricity and fossil fuels; power plants' fuel use
SOURCE:U.S. Energy Information Administration
DESCRIPTION: EIA's Electricity Data Browser (at eia.gov/electricity/data/browser ) collects nationwide data on power consumption and prices for the past decade, helping companies project future energy costs. Plant-level data reveals what fuel types are used, allowing companies interested in reducing their carbon footprints to estimate the environmental impact of operating in one location versus another.

What's Offshore

DATA: Locations of offshore oil and gas platforms; traffic patterns of marine vessels and locations of shipwrecks; offshore areas designated for wind energy and protected wildlife areas
SOURCES: Include U.S. Defense Department; Bureau of Ocean Energy Management; National Oceanic and Atmospheric Administration
Description: MarineCadastre.gov pulls data from 16 government and nonprofit sources into an interactive online map of U.S. oceans. It is primarily intended to help developers of wind and wave energy, but it also can be used by fishing and drilling companies.

Where the Sun Shines

DATA: Average annual global horizontal irradiance; photovoltaic plant locations; transmission line locations
SOURCES: Include National Renewable Energy Laboratory; Argonne National Laboratory; U.S. Interior Department
DESCRIPTION: Designed to help developers find sites for large solar power plants, the National Renewable Energy Laboratory's Solar Prospector (at maps.nrel.gov/prospector) pulls data on sunlight patterns, routes of transmission lines and locations of existing power plants into a single interactive map.

USDA

Food and Fitness

DATA: Americans' access and proximity to grocery stores; obesity rates; diabetes rates; physical fitness levels; proximity to fast food
SOURCE:U.S. Department of Agriculture
DESCRIPTION: The USDA's Food Environment Atlas (at ers.usda.gov) pulls food, health and socioeconomic data into various maps, allowing researchers to search for correlations between the availability of healthy food and obesity-related illnesses like diabetes. The maps also allow food-service companies to look for possible sites to expand.

National Nanotechnology Initiative

Nanotechnology

DATA: Nationwide locations of nanotechnology facilities, initiatives and degree programs
SOURCE:National Nanotechnology Initiative
DESCRIPTION: The Nanotechnology Resource Map (at nano.gov) shows the location of degree programs, facilities and research-and-development projects in the field of nanotechnology, giving businesses, investors and students interested in the technology a comprehensive overview of what's out there.
Mr. Schectman is a Wall Street Journal reporter in New York. He can be reached at joel.schectman@wsj.com.