For those Baltimoreans who want to live more sustainably and in closer touch with nature and the cultural gems around us, there's a new must-have map to get.

Folks who turn out for Rally for the River, Sunday's festival celebrating the Jones Falls, can pick up a Baltimore Green Map pinpointing more than 170 nature, culture and sustainable living sites within the city's portion of the Jones Falls watershed.  Farmers' markets, organic food vendors, museums, parks, consignment shops, green buildings, they're all identified by distinctive icons.  There's even a weeping eye for "blight" sites, places that need cleaning up. 

The flip side features a similar "green" map of Druid Hill Park, plus background information and a rundown of opportunities for action. 

The map is free (though admission to the festival is $5), and foldable to pocket size.  It's also viewable online here.  It's produced by Baltimore Green Map, a local affiliate of an international network of grassroots mapmakers who've charted sustainability resources in communities in more than 50 countries.

The idea behind the map is to encourage us to make a difference, environmentally, in how we get from place to place, where we shop and eat and spend our free time.  As such, it's a great response to those surveys we've written about before that found Baltimore lagging other cities in walkability and in reducing its carbon "footprint."

Baltimore Green Map was launched last year by the Jones Falls Watershed Association, with help from the city's departments of recreation and parks and planning.

Look soon for a green map of Loyola College's campus.  Janet Felsten, director of the project, says she's hoping to secure funding so she can launch a "campus green-map challenge." Her aim: chart eco-resources at places like Morgan State University, Towson University and University of Maryland, Baltimore County.  After that, who knows?  That may depend on you.   You can volunteer to help prepare maps, or just nominate a site, by going here. 

Rally for the River, by the way, runs from 8 a.m. to 2 p.m. Sunday and features a frog race, kayaking and canoeing, a skateboard competition, native plant nurseries and "earth-friendly" vendors, plus lots of other kids' activities.   And, of course, the neat thing is you get to walk or bike along the Jones Falls Expressway, closed for the afternoon to white-knuckled, road-raging motorists.  Admission is $5, but free for anyone 18 years old and younger.