6. THE SMOOTH SHEET 



231 



noted these differences and reconciled them 

 in the field, the hydrographic data shall su- 

 persede the photogrammetric survey. When 

 the discrepancies have not been resolved in 

 the field the following procedures are 

 applicable. 



(a) The photogrammetric locations and 

 elevations of bare rocks or islets shall be 

 accepted unless there is unmistakable evi- 

 dence of incorrectness. 



(b) The location of a rock awash or un- 

 covering at the sounding datum shall be 

 carefully examined to make certain that 

 there are not two rocks rather than an iden- 

 tical rock with two locations. Where the 

 feature is visible on the photographs and 

 the plot has been verified, the photogram- 

 metric location shall be retained. In other 

 instances all available data shall be evaluated 

 and the position considered most accurate 

 shall be accepted. 



(c) The locations of sunken rocks and 

 breakers and the notes relating thereto 

 should be accepted from the hydrographic 

 survey but it should first be determined that 

 the identical feature is involved. 



(d) The elevation of a rock awash should 

 generally be accepted from the hydrographic 

 survey because of the more definite tidal in- 

 formation available and the closer proximity 

 of the hydrographic party to the feature. 



The Photogrammetry Division should be 

 notified of adjustments made which signifi- 

 cantly aflfect information shown on the 

 photogrammetric surveys. 



6-90 Record of revisions. — Any revisions 

 made in the sounding record shall be con- 

 sistently entered in pencil of a color not 

 previously used in the record. No recorded 

 data or previous revisions shall be erased or 

 obliterated by a rejection line. If an un- 

 plotted least depth or other critical data at 

 one position is superseded by data recorded 

 elsewhere in the records, a cross-reference 

 shall be entered if not previously noted by 

 the smooth plotter. Each position verified by 

 protracting and all notes in the remarks col- 

 umn shall be check-marked. 



Revisions to recorded data made during 

 verification should be clearly explained in the 



sounding records and the justification for 

 each revision should be given where it is 

 not evident. No deviation from the original 

 recorded data shall be made unless this ap- 

 pears reasonable and is supported by other 

 evidence. Soundings should not be added to, 

 or revised on, the smooth sheet without also 

 showing the correct values in the sounding 

 record. 



The descriptive report shall be examined 

 and any revisions in reported data required 

 as a result of the verification shall be lightly 

 but clearly entered in black pencil. These 

 revisions will be inked in red by the reviewer. 



6-91 Junctions. — A junction shall be 

 made with each contemporary survey which 

 has been verified, or with the preceding sur- 

 vey of stable-bottom areas where specified. 

 Regardless of the stage of verification of 

 adjoining surveys the notation "JOINS 

 H (19 — )" shall be placed in the junc- 

 tional areas beyond the limits of hydrog- 

 raphy, in slanting mechanical lettering 2.5 

 mm. high. But the note shall not be inked 

 until junctional soundings are transferred 

 and inked. For surveys of different scales 

 the soundings shall be transferred from the 

 small-scale survey to the larger. Where a 

 sheet is surrounded by a number of sheets, 

 always make junction on one sheet if pos- 

 sible. Junctional soundings should be trans- 

 ferred from the offshore to the inshore 

 sheets. They shall be generally limited to 

 one line, or equivalent, beyond the limit of 

 hydrography on the sheet to which the 

 soundings are transferred. 



There are exceptions to the transfer of 

 junctional soundings. They should be omit- 

 ted where transferred soundings in com- 

 parable depths overlap or closely butt a 

 plotted sounding. Critical or significant 

 soundings, however, shall be transferred 

 even if deletion of other soundings is neces- 

 sary. Where unresolved differences in gen- 

 eral depths exist in the junctional area, the 

 less reliable soundings shall be omitted in 

 overlaps, thereby effecting a butt junction. 

 Where extensive hydrography overlaps su- 

 perseded hydrography of a specified adjoin- 

 ing survey, soundings shall not be transferred 



