□ LD MAPS HELP BUILD A NEW FUTURE 

 FDR THE EASTERN DYSTER 



By Kathleen Angidne 



I n the age of online mapping services, 

 paper maps may seem obsolete — but try telling 

 that to Eugene Ballance, an Ocracoke fisherman 

 who is transforming 1 18-year-old survey maps 

 of Pamlico Sound into blueprints for restoring 

 the Eastern oyster. 



Using satellite mapping and sonar imaging 

 technology, Ballance is modernizing a dozen 

 maps created in 1886 -1887 by Lt. Francis E. 

 Winslow, a naval officer who surveyed the 

 sound's then-abundant oyster reefs. 



The projections, or intersecting coordinate 

 lines, on Winslow's oyster maps are impeccable, 

 says Ballance, who is also a mathematician. 

 "They are better than anything that's been done 

 since then," he insists. 



Although Winslow's projections remain 

 accurate, the large, productive oyster beds he 

 described are gone. 



Eastern oysters (Crassostrea virginica) 

 have declined steadily in Pamlico Sound for 

 more than a century, mostly due to habitat 

 destruction, water pollution and disease. The 



disappearance of these "ecosystem engineers" 

 — which filter water and provide habitat for 

 dozens of aquatic creatures — is a trend Ballance 

 and others in coastal North Carolina are trying to 

 reverse. 



To transform Winslow's work, Ballance is 

 using Geographic Information Systems (GIS), a 

 computerized mapping program that combines 

 thousands of data points from a certain place into 

 "layers" of information. The result will be multi- 

 layered, digital maps that show where oyster 

 reefs once thrived and where they could likely 

 thrive again — information that helps scientists 

 and policymakers better focus restoration efforts 

 and dollars. 



Ballance received funding for the project 

 from the N.C. Fishery Resource Grant Program 

 (FRG), funded by the N.C. General Assembly 

 and administered by North Carolina Sea Grant. 



To get the thousands of data points 

 required for each layer, Ballance begins by 

 locating an oyster reef that appears on a scanned 

 version of Winslow's map. Next, he digitizes 



areas in the pixel coordinates of the scanned map. 

 Ballance then projects this information to latitude 

 and longitude coordinates using "control points," 

 or features on the map that remain in today's 

 surveyor databases. 



After completing these steps, Ballance must 

 field-check the new coordinate files. First, he 

 transfers the files to a hand-held computer and 

 verifies the coordinates using Global Positioning 

 System (GPS) technology. GPS uses satellite 

 signals to calculate exact positions of objects 

 on earth. Then Ballance samples the area with a 

 small, toothless scallop dredge to determine how 

 much of the reef is left. Finally, he uses sonar 

 imaging to take a picture of the sampled area. 



REFORMING RESTORATION 



Although the process is complicated, the 

 results simplify choosing a restoration site, 

 notes Jeffrey DeBlieu, director of The Nature 

 Conservancy's (TNC) Pamlico Sound Oyster 

 Reef Restoration Project. 



Continued 



FULL-PAGE left: A sdlid bed of 24D acres shown on one of Winslow's projections in Pamlico Sound. • FROM LEFT 

 TD RIGHT: An original illustration of Winslow's oyster survey maps from l 886-1 B87. • A map depicts oyster beds 



AND PRIVATE LEASES AT THE TIME OF WINSLOW'S SURVEY. • A MODERN NAUTICAL CHART OF CRAB HOLE SHOWS CURRENT AREAS 

 USED BY TRAWLERS AND POSSIBLE OYSTER SANCTUARY AREAS. * AN ILLUSTRATION OF HOW PIXEL COORDINATES ARE MATHEMATICALLY 

 TRANSFORMED TO LATITUDE AND LONGITUDE. • THE "MATCHLESS," A SCHOONER SIMILAR TO THE "SCORESBY" USED BY THE WlNSLOW 

 PARTY. • WINSLOW'S CREW CONSTRUCTED TRIPODS SIMILAR TO THIS ONE WHEN THEY NEEDED TO CALCULATE AN EXACT POSITION DN 

 THE WATER. 



COASTWATCH 15 



