# DNC Bulletin changes from 4/8/2014 to Present

**Purpose:**The DNC Bulletin is intended to provide guidance and clarification to NGA Contractors and Co-producers in collecting and maintaining DNC libraries for New Source Incorporation and Continual Maintenance. The purpose of this document is to provide insight to the changes that have occurred since the last release of the DNC Bulletin.  While the History tab within each of the bulletins does provide brief explanations, this document is intended to supplement and provide further information.

**Changes to DW Route Guidance (Bulletins 585, 847):**Changes were made to these bulletins regarding the determination of DW Routes, which removes the previous 30 meter depth requirement.  Further information was also provided regarding the IHO definition of DW Route.  Additionally consistency guidance between DNC Libraries was added to these bulletins.

**DGPS (Bulletin 651):**  This a new guidance bulletin for Chart #1 S51 DGPS, which is a station that provides GPS corrections.  

**Bulletin #55:**A change was added to this bulletin to include an exception rule regarding the 15 meter curve from sources.  The 15 meter curve exception is that the 15 meter curve is generally not necessary, unless a dangerous anomalous shoal occurs between the 10 and 20 which fall outside the normal gradient between 10 and 20.  Therefore, curves which may have values other than the traditional (exception of 15 meter), should be collected.

**Clarification of Bulletin #13:**  Clarification was added to this bulletin to avoid a possible conflict with Bulletin #814.  This bulletin refers specifically to reefs and hydro areas and therefore should not contain the words hazard area or obstruction, which are different features.

**Clarification of Hydro Areas and submerged wrecks (Bulletin #814):** Clarification was added in section K to remove ambiguity and provide consistency in collecting hydro areas for Wreck and other submerged obstructions.

**Clarification of Bulletin 692:**  This guidance in this bulletin was changed to give guidance for buoys that might appear on general scale libraries.  The title was also changed to 'General Scale Library Guidance for Buoys', rather than 'General Guidance for Buoy', which was misleading.

**Change in collection for Inshore Traffic Zone (Bulletin 576):**  It was determined that Inshore Traffic Zone collection be changed to Area FC031 as per DNC Spec rather the collecting as Line FC036.  This change would better fit the actual feature and would ensure proper migration to CFPE.

**Clarification of units of measure for information collected from NOAA Tabulation Tables (Bulletins 412, 414, 415, 416):**  Clarification was added in regards to the units of measure when adding NOAA Tabulation Table information to Notes.rat to emphasize that width and depths units should be in meters and decimeters and lengths should be in nautical miles (to the tenth of a mile).  

**Consistency for NAM Attribute for Offshore Installation Buoy Bulletins 540 and 544:**Changes were made to provide consistent guidance for NAM Attribute in regards to NAM and Light characteristics for Offshore Installation Buoy Bulletins.****

**Clarification to Bulletin #185:**Clarification to paragraph 3, "As many depth areas as possible must be created using the available depth curves from the source material." to “As many depth areas as possible must be created using the collected depth curves from the source material."

**Addition of Mariner Activated Sound Signals (Bulletin 767):**  An addition of Mariner Activated Sound Signal collection guidance was added to this bulletin.

**Various Radio Position-Fixing Stations that are considered obsolete (Bulletins 773, 775, 776, 777, 778, and 779):**Per S-4 section B-480, in addition to Bulletin 780 with regards to Aeronautical Radiobeacon S16, there are a number of other Radio Position-Fixing Stations that are also considered obsolete and there is no longer value in charting them.  These bulletins were changed accordingly.

**Clarification of ODAS Buoy sizes (Bulletin 733):**  Clarification was added to this bulletin to account for those buoys that are not superbuoy size.

**Definition clarification of Bulletin 56:**  Clarification of Jetty and Breakwater were changed in this bulletin.

**Change in Guidance for Mangrove and Marsh/Swamp/Reed features (Bulletins 142 and 143):**  Guidance was changed in both bulletins to reflect the "real world" nature of Mangroves and Marsh/Swamp/Reed areas and where they exist in relation to shoreline and intertidal zone.