TO THOSE DEVOID of imagination, a blank place on the map is a useless waste; to others the most valuable part," wrote the conservationist Aldo Leopold.
Leopold argued for an appreciation of nature that would go beyond building scenic overlooks by spectacular vistas, and he concluded:
"Recreational development is a job not of building roads into lovely country, but of building receptivity into the still unlovely human mind."
That was half a century ago, and despite great progress in preserving roadless areas and recognizing that wildness has intrinsic value, Leopold's proposition remains meaningful.
Geographers today talk of landscape in terms of "mental maps" -- basically, how we perceive ourselves in relation to our physical surroundings.
Such perceptions may be as important to how we treat the environment as the best-mapped knowledge of soil types, road networks, topography and drainage, or plant and animal distribution.
Mental maps can vary tremendously. For example, ask men and women whether the same part of Baltimore is a comfortable place to jog alone; ask them about it in daylight hours, and after dark.
Or travel through the "same" stretch of Baltimore County, first with a naturalist, then a developer, a farmer, a hunter, a trout fisherman.
I once spent a morning traveling a bay marsh with a local "progger," one of those watermen whose greatest pleasure, after a long day working the water, is to head back out into the marshes just to see what they can find.
I had an official map of the region, a good boating chart, but many of the names of points and creeks were not the progger's names.
While my chart named prominent features, the progger had a name for virtually every slough and ditch and cove and tump, also for every variation in the surrounding bay bottom, from which his community had scraped crabs and dredged oysters and gouged hibernating terrapins for generations.
With regard to the submerged bottom, it was as if the progger was moving in an additional dimension, invisible but spiritually sustaining.
Terrapin Sands, Hog Neck, Billy Lowe Gut, Kizzes, Back Landing, Dipper Point, Store Ditch -- it pleased him, he said, just to recite the names, as another might be solaced by the rosary.
Among indigenous peoples, mental mapping can be wondrously rich and full of subtle complexities -- even morality.
The anthropologist, Keith Basso, writes in an essay about the Apaches, "Stalking With Stories," how each part of their landscape is associated in storytelling with parables that are instructions on "how to live right."
"The person who told you may die," an Apache tells him, "but you won't forget that story; you're going to see the place where it happened maybe every day. You're going to hear its name and see it in your mind.
"That place [it could be as simple as a certain rock, or turn in the trail] will keep on stalking you "
As critical as I think awareness of mental maps is to our stewardship of the bay region, I think more traditional maps have great potential, too.
One of my favorites is the satellite view that shows the whole, 64,000-square-mile drainage basin from hundreds of miles high.
Only here can you appreciate how the bay is linked by dozens of rivers to a system nearly 16 times larger than itself.
You can see how the forest, though it still covers more than half the watershed, is unevenly distributed, packed into the far western, southern and northern portions of the watershed.
Along thousands of miles of critical bay and river shoreline, development and agriculture have virtually denuded the land of the vegetation that filters and buffers polluted runoff.
Only via satellite map can you appreciate the scope of the Susquehanna River, source of half the bay's fresh water, stretching from Maryland to the latitude of southern Vermont, where a meadowed ridge finally divides the bay from the Mohawk River Valley and the drainage of the Hudson River.
At the opposite pole, the communities of Smith and Tangier, Tilghman and Deal islands appear as small as grains of salt; yet their centuries-old, unique watermen cultures color all our mental maps of the whole region.
My favorite physical map is the "quad," or quadrangle map, which measures about 18 by 23 inches, and shows about 60 square miles, a thousandth of the satellite map's coverage.
It takes about 10 quads just to show Baltimore County. Based on aerial photos, and covering the entire United States, quads show one's home region with an intimacy that absolutely invites exploration.
Every logging road, farm ditch, cemetery, cornfield, pond, bog, gravel pit and home is identifiable. Additionally, they show the topography and enough of water depths to be useful for small boat expeditioning.
You can buy quads for about four bucks apiece, either from the Maryland Geological Survey at 2300 St. Paul St.; or by calling 1-800-USA-MAPS at the U.S. Geological Survey (which also sells satellite maps for $4 and up).
I guarantee that once you begin looking at quads of your area, you will be intrigued, mystified, and ultimately lured to get out and tramp or boat to numerous spots you never knew existed.
Mapping the bay region in earnest began with Capt. John Smith in 1608. His map, juxtaposed with a satellite image on facing pages in the Hammond-Harwood House Atlas of Historical Maps of Maryland, 1608-1908, shows what an astonishingly accurate job he did.
Physical mapping will get even better with a new federal project to aerially photograph the nation and put the result on CD-ROMs for computer manipulation.
But mental mapping is where we most need to work, acknowledging the aesthetic, spiritual and sacred connections that exist, or should, between us and the places we inhabit.