230 



HYDROGRAPHIC MANUAL 



position dot must be removed in such cases 

 in order to avoid any ambiguity. Position 

 numbers identifying critical data, such as 

 least depths, rocks, or obstructions, shall be 

 moved where it is apparent that the number 

 may be obscured in the inking of soundings 

 or other detail. 



6-87 Verification and inking of sound- 

 ings. — ^The penciled soundings shall be 

 checked against the sounding record and 

 inked in black. The cartographer shall be 

 guided by instructions contained in 6-53 to 

 6-60 with regard to spacing and selection 

 of soundings and size of numerals. The 

 soundings should generally be inked in 

 chronological order; however, in congested 

 areas it may be advisable to check through 

 the complete development before inking the 

 soundings. Where the hydrographer has in- 

 dicated that some of the closely spaced lines 

 are "not to be smooth plotted," the verifier 

 should assure himself that no critical sound- 

 ing has been overlooked (see 1-28 and 5-25). 



Soundings shall be revised where they are 

 erroneous, or are superseded by unplotted 

 peak or significant deep soundings, or re- 

 quire minor revisions for depth curve delin- 

 eations as specified in 6-63. Where penciled 

 soundings are overly congested or lack clar- 

 ity, selected soundings should be inked. 



Since the scanning of depths on the fatho- 

 grams has been verified in the field a de- 

 tailed re-examination of the fathograms 

 should not be necessary. Experience has dis- 

 closed that fathograms are sometimes inade- 

 quately check scanned ; that bar-checks for 

 specific days may differ significantly from 

 the average used for sounding reducers ; that 

 phase changes may be erratic and not con- 

 form to the average used in the sounding 

 record; and that interpretation of the bot- 

 tom trace in kelp or grass areas or with 

 respect to strays may be faulty. The verifier 

 should not hesitate to examine sections of 

 fathograms where discrepancies on the 

 smooth sheet occur or where deficiencies in 

 original scanning or checking affect the ac- 

 curacy and reliability of the survey. 



Bottom characteristics shall be inked in 



black using the correct abbreviations or 

 symbols (see 6-62). 



All notes in the record book shall be 

 checked with the smooth sheet plotting. Sym- 

 bols for rocks, limit lines and legends, and 

 other penciled data shall be inked on the 

 smooth sheet after verification of their ap- 

 propriate use and conformance with carto- 

 graphic standards. The verifier shall deter- 

 mine that all detail is represented as specified 

 in the instructions for smooth plotting con- 

 tained in this chapter. Only those revisions 

 should be made which contribute significant- 

 ly to the accuracy, completeness, and clarity 

 of the records and the smooth sheet. 



6-88 Revised depth curves. — Depth 

 curves shall be carefully verified for com- 

 pleteness and accuracy of delineations. The 

 curves shall be revised where there are sig- 

 nificant departures from correct bottom 

 delineations or where the selection of curves 

 on a steep slope does not conform to stand- 

 ard procedure. The verifier should not over- 

 look the delineations of curves on the boat 

 sheet, particularly in shallow areas where 

 the hydrographer was guided by local knowl- 

 edge and by delineations on aerial photo- 

 graphs (see 2-16). The verifier should also 

 refer to the photographs in specific instances 

 where hydrographic delineations in shallow 

 areas are incomplete or questionable. 



The verified depth curves shall be inked 

 as specified in 6-63. 



6-89 Verification of shoreline and rocks. 



— Inked topographic detail applied during 

 smooth plotting shall be inspected for omis- 

 sion and inaccuracy. Shoreline shall be re- 

 vised if it is symbolized incorrectly, or if it 

 is displaced more than the width of the inked 

 line, and to correct errors of omission. Rock 

 symbols shall be revised if they are exces- 

 sively large or small, and, where symbols are 

 too congested, the cartographer shall revise 

 the penciled work to conform with standard 

 practice as shown in Figure 81. 



There are occasional differences between 

 rock information shown on photogrammetric 

 compilations and the hydrographic survey 

 (see 5-67). When the hydrographer has 



