94 NAUTICAL CHART MANUAL 



CONSTRUCTION OF SMALL-CRAFT CHARTS 

 I. Prepare a layout, to scale, of the selected area on pre-determined format (see pg. 90). 



A. Assemble layout in cover showing continuity of coverage and positions of scales, compass 

 roses, insets, notes, photographs, etc. 



II. Present to Chief of Division, the layout, detailed specifications and proposed method of 

 compilation to be employed. 



A. Secure his approval and schediiled date of completion. 



B. One of the three following methods for compilation construction is presently used for 



"Folio" charts and "Route" charts: 



Method No. 1 



A new Mercator projection is computed and ruled on a stable plastic. The areas not 

 covered by conventional large-scale charts are compiled by rough drafting from evaluated scaled 

 source data on the new projection. The Compilation is then forwarded to the Reproduction 

 Division for engraving. From the resulting scribed copy a blackline print is furnished. This 

 print is then the base Compilation, and requires a complete application of geographic names, 

 notes, soundings and other miscellaneous type on a registered transparent stable plastic overlay. 



Method No. 2 



Mosaic to new Mercator projection, if required, positive scaled sources photographically 

 reproduced on stable base film. The scaled sources are made from the existing large-scale 

 conventional chart negatives. The resulting mosaic is the base Compilation. Compile and 

 smooth draft, on this mosaic base, all required hydrographic and topographic revisions. Re- 

 tain all geographic names, notes, projection values, etc. as per existing conventional chart. 

 Supplemental type stripper-film from existing charts is applied direct to the mosaicked base 

 Compilation. 



Method No. 3 



Same as Method No. 2 except for limited modernization of hydrographic and topographic 

 symbolization. Duplicate negatives, of existing large-scale conventional charts, are made by 

 the Reproduction Division and the required modernization applied to these negatives as per 

 furnished marked copy. Stable-base film positives, made from the corrected negatives, are 

 mosaicked and used as the base Compilation. This method requires a complete application of 

 new small-craft style type for geographic names, notes, soundings and miscellaneous type on a 

 registered transparent stable plastic overlay. 



