Page 675 the smooth sheet 7333 



Ozalid prints are photographic contact prints prepared in much the same manner 

 as blueprints. The developed print shows a colored line on a white background. 

 These prints are developed by a dry process and have a low percentage distortion. They 

 are satisfactory copies from which to transfer shoreline and control points, but it is 

 necessary that the hydrographic party make a pencil tracing for such transfer (see 7413 

 and 7561). 



7333. Printed Hydrographic Sheets 



^Vhere the hydrographic sheet layout can be made to conform approximately to the 

 air photographic sheet layout, and where there are numerous stations and intricate 

 shoreline details, printed smooth sheets and boat sheets are practicable and economic, 

 and will be furnished to hydrographic parties. The copies are printed at the scale of 

 the hydrographic surveys and on the same cloth-backed paper ordinarily used for boat 

 sheets and smooth sheets. All details are reproduced in black, including triangulation 

 and topographic station symbols, in addition to the projection and topography. 



The positions of the stations need not be checked by the field party. The symbols 

 for the topographic stations shall be left in black on the smooth sheets, but may be 

 encircled with additional 3 mm red circles on the boat sheets, if this is found desirable. 

 The triangulation symbols shall be left in black. Topographic station names shall be 

 assigned by the hydrographic party, and shall be shown in red on both the boat and 

 smooth sheets. (See also 744.) 



7334. Map Projector Transfers 



In some cases, although the boat sheets and smooth sheets are prepared in the 

 Washington Office, photolithographic reproductions are not made because of insufficient 

 time, or because the air photographic surveys are on an odd scale and a printing plate 

 is not yet available, or when their limits differ greatly from the hydrographic survey. 

 In such cases the projections are made on the projection ruling machine, and the shore- 

 line and control points are transferred (and checked) from the air photographic surveys 

 by means of the map projector (see 4854). The transfer is usually made in pencil and 

 shall be inked by the field party. A data record showing how the projection was made, 

 and how and by whom the shoreline and stations were transferred and checked is for- 

 warded to the field party with each smooth sheet. This record shall be included in the 

 Descriptive Report for the sheet (see Si2E). 



734. Projections for R.A.R. Sheets 



The best grade of well-seasoned paper shall be used for an R.A.R. smooth sheet. 

 The projection is constructed just as any other projection is, but immediately after its 

 completion and verification and the plotting and verification of the R.A.R. stations, 

 and before any inking is done, the distance circles must be drawn (see 7341), in order to 

 avoid complications due to distortion of the paper. Obviously, such projections should 

 not be requested from the Washington Office. 



7341. R.A.R. Distance Circles 



In contrast to other methods of hydrographic control, positions determined by 

 Radio Acoustic Ranging (described in chapter 6) are based on distances from the R.A.R. 

 stations and these are sometimes quite long. To facilitate plotting these distances and 

 to take into account any distortion which occurs in the smooth sheet after the projec- 



