6. THE SMOOTH SHEET 



203 



should not be used. The lines should be fine 

 and solid and not more than 0.2 mm wide. 



If the point of origin is within the limits 

 of the sheet, it shall be symbolized by the 

 appropriate station symbol and a 5 mm circle 

 of corresponding color (Fig. 79). If the 

 point of origin is off the sheet, the station 

 name should be added to several of the cir- 

 cles or in a legend on the sheet. 



The distance or time interval represented 

 by each circle shall be shown in ink of a 

 corresponding color with numbers about 2.5 

 to 3.0 mm high, and shall be positioned in 

 otherwise blank areas of the sheet, if 

 possible. 



Circles of equal angle are sometimes used 

 to plot sextant controlled hydrography (see 

 5-13). When required, these circles should 

 also be drawn soon after the projection is 

 made. The same principles apply with re- 

 gard to colors used and identification of the 

 stations and angles. 



6-12 Quality of drafting. — The approved 

 smooth sheet is the final graphic record of 

 an engineering survey ; an official govern- 

 ment document which is retained perman- 

 ently in archives of the Bureau. It is 

 frequently referred to after use in chart 

 compilation and photographic copies, often 

 at a one-half reduced scale, are furnished 

 to surveyors, engineers, geologists, and oth- 

 ers, including lawyers for use in courts. It 

 is evident, therefore, that the standard of 

 accuracy for smooth plotting and detailing 

 and also the clarity and neatness of the 

 drafting should reflect the high standard of 

 accuracy of the data plotted. The drafting 

 should not be artistic ; it need not be expert ; 

 it shall be neat, clearly legible and in ac- 

 cordance with the standards adopted for 

 hydrographic smooth sheets as specified in 

 this chapter. 



6-13 Character of lettering. — Mechani- 

 cal lettering sets or guides shall be used for 

 lettering all names and numerals except po- 

 sition numbers, soundings, buoy designations, 

 and rock elevations. In general, descriptive 

 notes should be in freehand lettering (Fig. 

 82). 



6-14 Orientation of lettering. — The let- 

 tering and symbols shall generally be aligned 

 with the parallels of latitude so as to be 

 read from the south. Where geographic 

 names cannot be lettered on an east-west 

 line, they shall be aligned at an angle or on 

 a curve so that they can be read from the 

 south (see 6-72). 



Regardless of the direction of the sound- 

 ing line, the individual soundings shall be 

 consistently oriented normal to an east-west 

 projection line, except in deep water where 

 it may be necessary or advisable to plot 3- 

 or 4-digit soundings at an angle. In such 

 cases, orientation of these soundings shall 

 be as consistent as possible and they should 

 be easily read from the south (Fig. 84). 



Both vertical and slant lettering are used 

 on the smooth sheet. The names of topo- 

 graphic features, which in general are the 

 names of everything above mean high wa- 

 ter, shall be vertical letters. The names of 

 hydrographic features, and in general all 

 features below mean high water, shall be 

 lettered in slanting letters. All numbers 

 including position numbers and soundings 

 shall be vertical, except that elevations of 

 bare rocks and rocks awash shall be slanting 

 numbers. Official names and designations of 

 aids to navigation either ashore or afloat 

 shall be lettered with slanting lines. De- 

 scriptive notes pertaining to all hydrograph- 

 ic features awash or covered at mean high 

 water shall be lettered with slanting lines. 



6-15 Placement of lettering. — Control 

 station names and most other lettering shall 

 be placed in the land areas in order to pro- 

 vide maximum clarity of hydrographic de- 

 tail (see 5-10). Wherever practicable, sta- 

 tion names should be on line with the bottom 

 of the station symbol and separated from 

 it by the space of one letter (Fig. 79). There 

 should never be any doubt as to the name 

 of a station. Where it is necessary to place 

 a name so far away that doubt may arise as 

 to its reference, a fine inked arrow or leader, 

 in the same color as the name, should be 

 drawn from the name to the symbol (Fig. 

 82). A large number of offset names, de- 

 scriptions and designations is undesirable. 



