NOAA s National Ocean Service / Office of Coast Survey

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2 Coast Survey OCS Maintains over 1000 nautical charts & 9 Coast Pilots Surveys over 3.4M SNM of oceans and lakes Conducts research and development in hydrography Thomas Jefferson Founder of The Coast Survey

3 Behind the Accuracy of Electronic Charts What Every Mariner Should Know about Electronic and Paper Charts

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5 How we made paper charts yesterday is reflected in the accuracy of electronic charts today...

6 Electronic Chart Components OCS 1) computer hardware, 2) real-time positioning (typically GPS) and other sensors, 3) electronic chart data and 4) software that displays and manipulates both chart data and real-time sensor input.

7 The Two Types of Electronic Charts Electronic Chart Display and Information System (ECDIS) Must comply with performance standards established by IMO. Standards specify components, features and functions of the ECDIS in which the primary purpose is to contribute to safe navigation. Electronic Chart System (ECS) Electronic Chart System (ECS) All other non-imo compliant systems.

8 Two Categories of Electronic Chart Data Raster Nautical Charts -- Scanned image of the paper chart -- Used in Raster Chart Display Systems (type of ECS) -- Show real-time vessel position projected on the chart image -- Impressive utility, but limited ability

9 Two Categories of Electronic Chart Data Vector Chart -- A database that contains points, lines and polygons that correspond to chart features -- Data is intelligent -- Chart features can be attributed

10 Before the advent of GPS, chart makers were secure in the knowledge that the horizontal accuracy of features portrayed on a paper chart was more than adequate to serve the mariner s s needs.

11 25 years ago

12 The nautical charting world has been turned upside down in the past twenty years

13 The overall horizontal accuracy of data portrayed on paper charts s is a combination of the accuracy of the underlying source data and the chart compilation process. SOURCE USCG Aids to Navigation USACE Dredged channels NOAA Shoreline and non-channel depths OTHER USPS, USCGAux, Private Surveyors, etc. PRODUCTS Paper Charts Lithographic Print on Demand Raster Charts Update Service Vector Charts Electronic Navigational Charts

14 1994 NOS Survey 1:10, NOS Survey 1:40, NOS Survey Various NOS Survey Various

15 1800s positioning methods have changed over the years, but it s s still mast mounted GPS 2007 Sextant

16 Hydrographic Survey Over 50 percent of the depth information found on NOAA charts is based on hydrographic surveys conducted before 1940.

17 Pre Present Soundings obtained by hand lead-line line Soundings obtained by single-beam echo sounder Multi-beam Side Scan Sonar Soundings obtained by side scan sonar and multi-beam resulting in 100% bottom coverage All examples at the same line spacing

18 Early two-boat wire drag technique used to clear channels to a prescribed depth.

19 The shoreline found on most NOAA charts is based on photogrammetric or plane table surveys that are more than 20 years old.

20 Before NOAA s suite of charts was scanned into raster format in 1994, all chart compilation was performed manually.

21 In the late 1980's and early 1990's, NOAA converted all of its charts to NAD83 from NAD27.

22 Many electronic chart positional discrepancies that are observed today originate from graphical chart compilation techniques of the past.

23 High accuracy aerial photography reveals similar discrepancies between the true shoreline and the charted shoreline.

24 Some mariners have the misconception that because charts can be viewed on a computer, the information displayed has somehow become more accurate than what appears on paper.

25 Addressing the Accuracy Problem A national suite of highly accurate electronic charts will be a primary cornerstone of a safe and efficient Marine Transportation System in the 21 st century.

26 NOAA is in the process of building a new charting database that will address some of the inadequacies of today s s electronic charts.

27 NOAA s approach to building ENCs addresses the horizontal accuracy issues.

28 Positions of all wrecks, obstructions and other hazards that appear on the chart are researched to obtain original positions. This data is then incorporated into the ENC. The remaining and less significant data is vectorized from the paper chart.

29 Over time, ENCs will be enhanced with higher accuracy data. Multi-beam Current 21 st Century Data Acquisition Digital USACE Survey

30 Ultimately, NOAA envisions printing the paper charts from the ENC database.

31 Mariners in the 21st century expect highly accurate electronic charts. NOAA is working toward that goal. Selectable Views Channel Fly-through Photorealistic Bottom Contours Charts of the Future?

32 Remember, when navigating with electronic charts in areas without navaids, give charted features such as rocks, wrecks, etc. as wide a berth as you did when navigating with a paper chart, the zoom capability does not make the object more accurately charted and continue using the wheelhouse windows.

33 Navigation Response Team (NRT)

34 Special Project completed - Single-beam centerline survey of St. Marys River to produce datum step chart Special Project completed Shoal sounding and wreck survey in St. Clair River Main 2006 Project side scan sonar, single beam hydrography, and ENC Validation, vicinity of Chicago Special projects requested for surveys at Silver Bay and Marquette

35 1 1 St. Clair River Special Project Obstruction Disproval New Wreck Found Shoal Disproval Obstruction Verified 2 3 4

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40 Chicago Harbor Survey

41 Print on Demand Definition: The use of large format plotters to print charts when ordered using up-to to-date digital files. Product Characteristics: OCS Up-to to-date with all Notice to Mariners when printed Water-resistant resistant and abrasion resistant Extra information outside the neatline in two varieties Enhanced colors Next day delivery Status: Officially recognized product meeting Federal carriage requirements Book Charts are not yet available Produced under contract for NOAA by

42 Chart Update Service Definition A weekly electronic file that updates a raster nautical chart or an ENC Product Characteristics All USCG, NIMA, CHS Notices applied every week Update file delivered by e or downloaded from the internet Automatic application of update to chart Old chart, new chart, and patch can be viewed Status NOAA in continual maintenance mode Technology developed, tested and in-place Available by subscription through CRADA partner OCS

43 Download Raster Charts And ENCs free on the Internet!

44 For More Information Contact: Brian Link NOAA Navigation Services Division 1431 Beach Street Muskegon, MI

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