The Office of Coast Survey is implementing a unified, geospatial database for storing and accessing NOS hydrographic survey data. This supports new marine charting requirements and technologies, as well as providing for diverse data access mechanisms for all other users.
The history of hydrographic surveying is long and interesting, encompassing many changes in technology and procedures starting from the 1800’s and continuing through today. Until recently the product, and only bathymetric output, of a given survey was a “smooth sheet” plot of the data at a given scale (e.g. 1:10,000 or 1:20,000). In a series of efforts, many of these smooth sheets have been digitized and made available to the public at the National Geophysical Data Center website. More recent hydrographic survey datasets have been collected and processed digitally; these have been added to the NGDC repository through a series of digital translations.
The new repository of digital hydrographic survey data is built on a spatially enabled relational database (Oracle). Using this foundation enables direct connections with any standard databases, connections with diverse GIS clients, and any other tools which can read and write SQL. The data can be represented in a variety of units, geographic projections and formats. The database can also execute spatial operations on the data before streaming it across the network which decreases network load and improves responsiveness. The system also benefits from all of the robust enterprise tools for data backup, availability and redundancy.
All of the digital hydrographic survey data in the database has undergone a series of quality checks. Many of these occurred during the data acquisition and processing steps before becoming an official signed smooth sheet. These assure that the data represent the best available view of the navigability of a particular area of seafloor at the time it was collected. Subsequently, additional checks ensure that the digital data is consistent with the smooth sheet data.
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