6. THE SMOOTH SHEET 



237 



values of latitude and longitude and shall 

 be labelled NA 1927 Datum. 



6-104 Chart comparison. — The survey 

 shall be compared with the latest print of 

 a large-scale chart or current chart drawing 

 of the area for the purpose of evaluating 

 the charted data and adequacy of the survey 

 to supersede all prior surveys for charting 

 purposes. The comparison should be made 

 with the largest scale chart of the area un- 

 less the chart of next smaller scale was re- 

 vised first and is the better medium for 

 comparison. Each charted sounding and in- 

 dividual item within the area of the hydro- 

 graphic survey shall be compared and check- 

 marked on the chart or an overlay of the 

 drawing. 



The comparison is a relatively simple pro- 

 cedure when the common area involves only 

 a comparison of soundings previously made 

 with prior surveys (see 6-99). The most 

 complicated comparison occurs in areas of 

 very irregular bottom and the chart includes 

 data from advance information from the 

 new survey in the form of chart letters, boat 

 sheet hydrography, unverified and unre- 

 viewed hydrography, Corps of Engineers 

 surveys, Coast Pilot field inspection reports, 

 and miscellaneous reports from other sources. 



In the event that the comparison and re- 

 view reveal an uncharted danger or condi- 

 tion important to navigation, the reviewer 

 shall immediately inform the Chief, Nauti- 

 cal Chart Compilation Section. The data 

 shall be indexed on the Nautical Chart Stand- 

 ards and considered for inclusion in the next 

 Notice to Mariners regularly published by 

 the Navy Hydrographic Office. 



Significant charted soundings or features 

 which have not been previously disposed of 

 and which conflict with the reviewed sur- 

 vey or which should be retained on the 

 chart as supplementary data, shall be evalu- 

 ated and recommendations made for their 

 disposition. In general, comparison with sur- 

 veys of other organizations should be re- 

 stricted to charted information only. Only 

 in exceptional cases is information from 

 such sources actually carried forward to the 

 new survey. 



Controlling depth notes charted from sur- 

 veys made prior to the present survey should 

 be compared with the new survey. Con- 

 trolling depth notes charted from surveys 

 subsequent to the present survey supersede 

 the present survey information and a com- 

 parative evaluation is not required. 



The aids on the latest aid proof should be 

 compared with the survey to see whether 

 they adequately mark the feature or serve 

 the purpose intended. New positions of 

 shoals found in the area or channels not 

 adequately marked by the buoys shall be 

 noted. The charted and survey positions of 

 fixed aids to navigation should be compared. 



6-105 Review report. — At the conclusion 

 of the review a report shall be prepared for 

 insertion in the descriptive report. The re- 

 port is a summary of pertinent facts relating 

 to the survey and the detailed comparisons 

 made with prior surveys and other chart 

 source material. Specific evaluations are 

 given covering the adequacy of the present 

 survey to supersede prior survey data and 

 charted information. The report should serve 

 as a guide to the chart compiler and form a 

 basis for instructions for additional field 

 work when considered necessary for comple- 

 tion of the survey. Sections and subject mat- 

 ter of the report shall be in the order and 

 form indicated in the following sub-sections : 



1. Description of the area. — The area 

 should be described briefly. State the loca- 

 tion, general character of the area surveyed, 

 and nature of the submarine relief. 



2. Control and shoreline. — When the ori- 

 gin of the control is adequately described in 

 the descriptive report a short reference to 

 the appropriate section is sufficient. Include 

 supplementary information resulting from 

 verification and review when necessary. 



The source of shoreline data shall be 

 stated, specifically identifying the advance 

 or final photogrammetric manuscripts where 

 these were used in the final shoreline com- 

 parison. 



3. Hydrography. — A summary evaluation 

 of the hydrography should include specific 

 statements regarding agreement of sound- 

 ings at crossings, completeness with which 



