How green is your city? The Trust for Public Land, a national land conservation nonprofit founded in 1972, recently analyzed the 40 largest U.S. cities using mapping technology and demographic data to determine how well each metropolis is meeting the need for parkland.

The Trust's ParkScores are based equally on three factors: park access (which measures the percentage of residents living within a 10-minute walk of a park), park size/acreage (which is based on a city's median park size and the percentage of total city area dedicated to parks), and services and investment (which combines the number of playgrounds per 10,000 residents and per capita park spending). The scores were then reviewed separately by local park system leaders to ensure accuracy.

ParkScore was designed to help local communities improve their park systems and identify what areas need new parks the most.

You can't have a great city without a great park system, said Christopher Kay, chief operating officer of The Trust for Public Land. Studies show that parks help children and adults get the exercise they need to stay healthy, generate hundreds of millions of dollars in economic activity, and help bring neighbors together. The Trust for Public Land hopes that ParkScore inspires cities to focus on parks, and we're eager to work with municipal leaders and volunteers to help them build the best park systems imaginable.

No city in the inaugural review garnered a perfect score, and Kay said every city could improve.

It's critical to act now, he said. A concerted effort to improve local park systems not only means a better ParkScore, but also a healthier, more beautiful, and more vibrant city. That's something all city leaders should strive for.

TPL's ParkScore website uses advanced GIS (geographic information system) computer mapping technology to created digital maps evaluating the 40 largest U.S. cities' parks.

At the bottom of the list were:

No. 31 Tucson (tie); No. 31 Memphis (tie); No. 33 Oklahoma City; No. 34 Jacksonville; No. 35 San Antonio; No. 36 Indianapolis (tie); No. 36 Mesa, Arizona (tie); No. 38 Louisville; No. 39 Charlotte; No. 40 Fresno.

Other cities offered their residents a wide array of public parks. Press Start for a look at the top 10 cities in the Trust for Public Land survey.