d. Survey Accuracy, Data Processing, and Quality Control . The accuracy 

 criteria of the profile surveys are 0.1 foot vertical and 1.0 foot horizontal. 

 Since standard survey techniques and equipment were used to collect all data, 

 the random and systematic errors of measurement were under control and did not 

 affect the data. However, the leveling was not closed for each profile survey 

 for any but the 1972 data, and personal errors may be present in the elevation 

 data. Czerniak's (1973) quality control study indicated a 25-percent probabil- 

 ity that the elevation of a surveyed point will be recorded in error by ±0.1 

 foot. Since the probability of multiple occurrences of this rounding error on 

 the same profile is very small, the error, if present, does not adversely affect 

 data analysis. 



Beginning in 1968, survey data were recorded in notebooks in the field, 

 then transferred to optical scanning forms and sent to CERC for processing. 

 Prior to 1968, data were also recorded in field notebooks, but surveyors hand- 

 plotted the data on standardized graph paper. At CERC, the survey data were 

 logged and read on an optical scanner (IBM 1232 Optical Mark Page Reader) which 

 converted the data to punchcard format. All pre-1968 plots were digitized 

 (Auto-Trol 3400 digitizer) and placed in the same punchcard format. 



The cards were then processed into a Univac 1108 or CDC 6600 computer, 

 using an editing program that displays the profile elevation-distance points 

 on a printer plot. Obvious errors, such as points significantly displaced 

 from the general trend of the profile, or possible errors of points less 

 displaced, were noted. Copies of the data listing and a description of the 

 possible errors were sent to the surveyors for correction or comment. When 

 all errors were satisfactorily corrected, a final edit check was made before 

 converting the data to magnetic-tape format. 



Further quality control was made on the survey data during various stages 

 of analysis. When anomalous results were obtained in a particular analytical 

 step, an extensive check of the initial survey data was made, using the original 

 field notebooks. The detailed quality control study of subsets of BEP profile 

 data indicated that less than 1 percent of the surveyed points contained small- 

 magnitude personal errors, and that most of the errors remaining in the data 

 after standard editing were round-off errors in the elevations which did not 

 affect the results. 



2. Aerial Photos . 



Aerial photos were used to determine beach changes both at single points 

 through time and along the beach at one time. Dates of the photo missions are 

 given in Table 5. Most of the flights originated near Sandy Hook and were flown 

 at low tide. Contact prints of the original images were used with a scale of 

 approximately 1:9600. 



a. Base Map and Measurements . A Bausch and Lomb Zoom Transfer Scope, which 

 allows the viewing of two separate images simultaneously, was used in the analy- 

 sis. The operator viewed an aerial image and a base map of the same area and 

 traced a superimposed image, such as the waterline, from the photo onto the map. 

 Differences in scale and tilt were matched so the two images appeared superim- 

 posed. Thus, scale variation error and tilt errors were eliminated. 



The base map was constructed to provide a constant scale for comparison of 

 parameters between different sets of photos. Reference points on the base map 



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