40 NAUTICAL CHART MANUAL 



TOPOGRAPHY 



GENERAL STATEMENT 



Topographic detail is shown on nautical charts to help the mariner determuie his position 

 at sea in relation to fixed visible objects. It is compiled primarily from photogrammetric 

 surveys made by this Bureau and supplemented by other sources when necessary. 



Topographic maps made from the surveys are used for planning, compiling, and correcting 

 topography shown on the charts. The map manuscripts are available during different stages 

 of their compilation as follows: 



Preliminary Manuscript 



Compilations from meager or xmverified control. Preliminary manuscripts are not dia- 

 grammed on the Standards and should never be used for nautical chart compilation. 



Incomplete Manuscript 



Controlled plots with incomplete detailing; prepared for the use of field parties. Incom- 

 plete manuscripts are diagrammed on the Standards with the pencil notation "History," but 

 shall not be used for compihng or correcting the charts. 



Advance Copy, Advance Print, Advance Manuscript 



These synonymous terms indicate a controlled plot with detailing complete except for 

 revisions made during review and may be used for compiling or correcting the charts. Nor- 

 mally, any revisions made as the result of the review are minor and rarely affect the chart. 

 The numbers assigned the manuscripts in this advanced form. are indexed on the Standards in 

 pencil, indicating these maps must be marked partially applied on the chart History until the 

 reviewed manuscripts are apphed to the charts. 



Reviewed Manuscript 



These are the final basic siu-veys which may be completely applied to the charts. All 

 applications shall be indicated on Form C&GS-8352 "Record of Apphcation To Charts" in the 

 Descriptive Report. Cartographers taking charts in hand for correction should obtain authori- 

 zation to apply these surveys completely, if time permits. 



Revision Sheets 



Revision Sheets, sometimes called "RS Sheets" are copies of either advanced or reviewed 

 manuscripts to which are made corrections from aerial photographs, taken after the date of 

 the Advanced Print. They are assigned an R.S. niunber which is different from the original 

 manuscript number. Revision Sheets may be applied to the charts in the same manner as 

 the advanced or reviewed manuscripts. 



