Creating a GIS from NOAA Electronic Navigational Charts
James Hawks and Matthew Austin NOS Office of Coast Survey Coast Survey Development Lab
Introduction
Background-- Nautical Charts, ENCs, S-57 ENC Direct to GIS Website Users Benefits Web Services Future Direction Conclusion
What is a Nautical Chart?
A graphic depiction of the marine environment
Nautical Charts Show:
Nature and form of the coast General configuration of the sea bottom Water depths Aids to navigation Topographic aids to support navigation Used primarily as tool for safe navigation
Chart Suite Coverage ~1000 charts
Navigation Product: Electronic Navigational Charts
Electronic Navigational Charts (ENC) are databases of chart features used by navigation systems to produce a chart-like display.
What is S-57?
International Hydrographic Organization (IHO) for Transfer Standard for Digital Hydrographic Data Uses International Standard Organization (ISO) 8211 file format
Platform independent structure
Provides a standard catalog for chart features ENC is a product specification for S-57
S-57 Object Catalog
Chart features belong to object classes Over 180 object classes defined Each object has set of descriptive attributes Object classes encoded as acronyms Attributes encoded as acronyms and enumeration Includes attribute data types and value domains
Using ENCs in GIS
Rich structure of the object catalog requires the use of data decoders to make sense of information contained in S-57 Off the shelf GIS software packages do not support ENC in native S-57 format S-57 standard is complex and hard to fully integrate in GIS
ENC Direct: The GIS Solution
ENC Direct
Provides NOAA ENC data as online GIS Uses ESRI ArcIMS internet mapping service Data is available for download in GIS multiple formats through Spatial Direct online data transformation Download can be customized to fit user requirements Large Scale ENCs currently available Updated monthly to include new coverage and ENC updates
NOAA ENC data conversion
Safe Software’s Feature Manipulation Engine (FME) used for data conversion Custom translation developed in house Converts S-57 to shapefile and ArcSDE Chart features are merged together to create seamless GIS layers from NOAA ENCs
GIS layers of aggregated nautical features covering US waters
Contiguous information about Nautical Chart features available in GIS layers Example: ENC Direct coastline layer contains information from 400 ENCs of the same scale that have been glued together Over 200 GIS layers available
ENC Direct to GIS
Layers have been symbolized to give a chart like display S-57 object classes have been organized into meaningful groups based on ESRI’s S-57 data model Layers have scale dependency to improve performance. Layers are only visible at a particular scale
Data Download
Zoom in
Choose data format, and spatial extent
Select Data
Data is clipped, zipped and shipped
Benefits
Streamlines and expands access to NOAA ENC data for non-navigational use Visualization of NOAA ENCs online Access to multiple cohesive chart featuresSoundings, Shipwrecks, Harbors, Marine Sanctuaries, Coastline, Landmarks
Web Services
Web Map Services and Web Feature Services Eliminate need for data download Data can be view directly through desktop GIS clients (ESRI clients only at the moment) and stacked with other web services
ENC Direct Web Service viewed in ArcMap
ENC Direct Architecture
Web Server: Windows 2003, Apache, Tomcat, ArcIMS 9.1, Spatial Direct Data Server: Red Hat Linux, ArcSDE 9.1, Oracle 10g
Users
USGS National Map US Coast Guard Homeland Security Coastal Managers Coastal Engineers Marine Modelers State and Local Government Private Sector
Conclusion
ENC Direct to GIS expands access and usage of NOAA ENCs For further information, contact: enc.gis@noaa.gov
http://nauticalcharts.noaa.gov/csdl/ctp/encdirect_new.htm