Corps districts throughout the country forward their survey blueprints to NOAA. These blueprints were traditionally provided in paper format. However increasingly, the Corps provides NOAA with digital versions of surveys. Some districts compute their own channel tabulations and provide this information to NOAA in addition to the surveys. Other districts provide NOAA with the surveys and NOAA cartographers create the channel tabulations.
In most cases, new USACE channel surveys will precipitate changes to currently charted channel tabulations and legends. This information may be critical to mariners; therefore, NOAA generates chart updates that are forwarded to the Coast Guard and National Geospatial Intelligence Agency for inclusion in Local Notice to Mariners and Notice to Mariners.
NOAA and the Corps are working closely to develop a channel framework database. With the advent of high accuracy positioning and electronic charts, it is imperative that the precise geographic coordinates of channel boundaries be available to the mariner. The channel framework database consists of the outside channel limits, quartered sections of the channel as well as reach locations within the channels.
Before new construction can take place in or along a waterway, individuals must apply for a permit from the USACE. Corps districts throughout the country forward these permits to NOAA. Usually, there are engineering plans that accompany the permit. However, NOAA does not automatically receive “as-built” drawings, once the project is complete. Very often, NOAA cartographers will have to track down “as built” drawings after the construction is completed. From these drawings, additions, deletions, and changes to the chart can be made.
NOAA and the Corps are working together to develop more seamless and consistent data exchange formats. Corps districts do not use a universal software system for processing channel surveys. Most districts currently process and plot surveys using computer aided draft and design (CADD) software such as MicroStation or AutoCAD. NOAA’s paper and raster chart production system is based on MicroStation software. However, both NOAA and the Corps recognize that efficiencies can be gained by moving their processing environments to Geographic Information Systems (GIS). NOAA and the USACE are in the process of building new charting databases that will lead to standardized data exchange. The Electronic Navigational Chart (ENC) is a vector database of chart features being built to the International Hydrographic Organization's S-57 standard. NOAA, as the U.S. hydrographic office, is exclusively responsible for production and authorization of ENC data in U.S. coastal waters and Great Lakes. The Corps has also adopted the S-57 format to build its suite of Inland Electronic Navigational Charts (IENC). These electronic charts will serve users of inland waterways who have traditionally relied on Corps paper charts. The Corps is moving toward providing NOAA with electronic survey data in S-57 format.