DOCSLIB.ORG

Indian Electronic Navigational Charts (Encs) Programme: Marching Towards Self-Reliance

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Indian Electronic Navigational Charts (Encs) Programme: Marching Towards Self-Reliance Indian Electronic Navigational Charts (ENCs) Programme: Marching Towards Self-Reliance Dr. U. K. Singh and Rajesh Kumar Civil Hydrographic Officer ([email protected]) Principal Civil Hydrographic officer Indian National Hydrographic Office 107-A, Rajpur Road, Dehradun (UA), INDIA-248 001 Tel: 91-135-2747365-211 (Extn.) Fax: 91-135-2748373 ABSTRACT : Marine navigational safety is the prime concern of Hydrographic Office (HO) in order to provide safe and efficient navigation and for the development of nation maritime policies. The efforts for safe and efficient use of hydrographic products and services have paved way for development of the Electronic Navigational Charts (ENCs). The recent developments in Electronic Navigational Charts(ENCs) and Electronic Chart Display and Information System(ECDIS) are panacea in this direction. With this pertinent ambition the Electronic Navigational Charting programme of India started in 1997 with a vision to gain a greater appreciation and understanding of the use of electronic charts when operating in its Waters. More than 206 ENC’s were generated for all 6 usage bands in short span of 5 years. This paper describes vision, initial accomplishments, production flow of ENC and future vision of Indian National Hydrographic Office (INHO) in development and marketing of its Electronic Navigational Charts. The paper also described the regional cooperation in production and setting-up of RENC for North Indian Ocean Hydrographic Commission (NIOHC). 1. INTRODUCTION : Navigation of ships through nation's coastal waters and channels using improved navigational systems and new navigation technologies is the prime concern of any Hydrographic Office (HO) in the world. HOs have been haunted in past years, by shipping disasters, which have questioned the safety of life at sea, both to the mariners and ocean environmentalists. The International Marine Community is thus looking for an effective navigation technology for improved navigational safety. In recent years, HOs all over the world are playing leading role in development of Electronic Navigational Charts for marine community so that vessels can navigate safely on their voyage across oceans. Digital cartography has influenced the field of navigation in a big way with the induction of Electronic Chart Display & Information System (ECDIS). SOLAS V/19-2.4 provides the opportunity to significantly enhance safety of navigation and efficiency in maritime operation by accepting an ECDIS as meeting chart carriage requirements. The two integral parts of ECDIS are the Display System and the Electronic Navigational Chart Database (ENCDB). The ENCDB consists of navigational data accumulated through ENCs. The ENCs has paper nautical chart equivalence. The quality and contents of nautical charts is the cornerstone of safety at sea, and is strictly controlled by international agreements. Thus the industrial development of technically elegant solutions is not enough, the products must meet a well-defined standard for international approval of IMO/IHO. As a result an international standard was established by IHO which called as “S-57- IHO Transfer Standard for Digital Hydrographic Data”. In order to fully realize these enhancements to safety and efficiency, ENCs accountable from Indian National Hydrographic Office (INHO) must achieve complete coverage of uniform quality and availability through user-friendly services. INHO is responsible for the production of navigational charts and allied publications to facilitate safety of navigation in Indian Waters. And being the leading hydrographic nation in the North Indian Ocean region, INHO is committed to provide ENCs coverage in the region. With this endeavor in mind the Electronic Navigational Charting programme of India started with a vision to gain a greater appreciation and understanding of the use of electronic charts when operating in its waters for safe and efficient marine navigation. Beside this the purpose was to develop an information system in pace with technological development and demonstrate world that India is capable of producing full coverage of its National Chart Series digitally and as per the specifications laid down by IHO/IMO. 2. INITIAL ACCOMPLISHMENTS IN INDIAN ENC PROGRAMME : With a solid core of experienced cartographers and hydrographers, equipments and the nation’s most extensive holding of bathymetric and hydrographic data, a quest for development of Electronic navigational Charts started in 1997. For INHO creating Electronic Navigational Charts for its waters was a very prestigious project. Initial accomplishments include requirement of sources for generating ENCs and populating it with various authenticated data. The obvious choice for source for its creation was initially paper chart. Since Indian paper charts are in Everest spheroid, datum transformation is required to shift into WGS’84 spheroid. Calculation for spheroidal shift was based on the Least Square techniques was used from data observed from GCPs at West Coast, East Coast and Andaman & Nicobar regions of India. Although limitations of a paper chart is that if it is used for creation of ENC to enrich it, all the limitations corresponding to the scale would be transferred to ENC. But due to financial and other constraints, it was decided to digitize the paper chart information for the purpose of creating ENCs rather than going for original source material. Then came the problem of finance and after careful review, the task was contracted to an Indian firm who utilized CARISTM Suite of Software for implementing S-57 standards of IHO/IMO for generating full coverage of ENCs as per national chart series of India. The scale of a ENC is determined by the type of navigation for which it is intended, nature of the area to be covered and quantity of information to be shown. Various scale terms are used in the S-57 IHO Product Specifications Appendix B, such as Overview, General, Coastal, Approach, Harbour and Berthing, which belongs to Chart of medium-scale, large-scale, and coastal series. The IHO product specifications for ENCs although mentions navigational purpose of ENCs, but it did not specify the scale range that should be applied to each ENC. The reason behind it is that different HOs have their own scale ranges to meet the navigational purpose. The Indian Hydrographic Office followed INT M4 chart specifications for the simple reason that each ENC cell is roughly equivalent to limits as per paper chart. 3. PRODUCTION FLOW OF INDIAN ENC : INHO used Caris Editor and Caris HOM, which are two modules of Caris suite of Softwares to produce its ENCs. A conceptual model of production flow has been shown in Figure 1. Header file for chart was prepared according to the initial parameters of nautical paper chart and hence NEMR coordinate system was adopted. This coordinate system is best suited if position of features on map is based on projection. Extraction of data was made by on-screen digitization with aid of in-built INT-2 (Symbol & Abbreviation) symbols library and keeping raster chart superimposed in backdrop of the project’s header file. Digitized features are broadly classified into 3 groups viz., point, line and area. The final content of digitized features were checked with the raster content in respect of type and position of features. The map product is now transform from existing Everest spheroid to World Geodetic System’ 1984 (WGS’84) spheroid as ENC need to be prepared in this world-wide accepted spheroid as per IHO directives. This transformation required header file in LLDG type which deals the coordinate system in decimal of degree and best suited for ENC creation. A Cell of ENC is defined as an area on the surface of real earth bounded by two meridians and two parallels that means a Cell does not has projection like paper chart. In order to create a cell, cell rectangularity process was run which re-adjusts the features at the corner area of map particularly in case of large scale nautical chart at Transverse Mercator projection.. All the features of point, line and area were exclusively defined with their given specification. Meta data regarding survey reliability, navigation system, publication information and coverage of ENC are also added at this juncture of production flow. Features in the cell are spatially related to each others and hence network as well as polygon topology test run and rectify till all the features becomes topologically correct. This determines the inter-spatial relationship between objects. In order to link these features to cell’s database, keys are assigned automatically by software and thereafter features converted to Object, an intelligent feature. Assigned keys are unique code in worldwide sense so that any maritime objects won’t has common ID number in any part of world ENC database. In Object mode, a point is known as a node, a line is an arc and an area is a polygon. There are various types of data-identifiers for these Objects, which help user to filter the display of data. Ra ster Header (NEMR Extraction P of Data R O Spheroidal Shift C Chart in E WGS’84 S S Cell Creations Feature F Creations NO L Topology O W Objects NO Objects QA/QC ENC S-57 Database Validation INHO ENCs C-MAP Distribution Figure 1: Conceptual Production Flow Diagram of Indian Electronic Navigational Charts. Validation or post-production analysis of the ENC is a process to ensure a supply of high quality consistent data to end- user. As ENC is to be used in ECDIS therefore its INHO commitment to follow and ensure proper QA/QC norms as per IMO SOLAS regulations. INHO has ensured fully that all its ENCs are error free and in tuned to IHO/IMO standards. Stringent QA/QC checks were employed to final cell and subsequent updates to follow that resultant product i.e. ENCs are fully compliant as per IHO Product specifications and as a result India attained full ENC coverage of its Indian Waters as shown in Figure 2.
Load more

Recommended publications
  • Chapter 13.2: Topographic Maps 1
    Chapter 13.2: Topographic Maps 1 A map is a model or representation of objects and terrain in the actual environment. There are numerous types of maps. Some of the types of maps include mental, planimetric, topographic, and even treasure maps. The concept of mapping was introduced in the section using natural features. Maps are created for numerous purposes. A treasure map is used to find the buried treasure. Topographic maps were originally used for military purposes. Today, they have been used for planning and recreational purposes. Although other types of maps are mentioned, the primary focus of this section is on topographic maps. Types of Maps Mental Maps – The mind makes mental maps all the time. You drive to the grocery store. You turn right onto the boulevard. You identify a street sign, building or other landmark and know where this is where you turn. You have made a mental map. This was discussed under using natural features. Planimetric Maps – A planimetric map is a two dimensional representation of objects in the environment. Generally, planimetric maps do not include topographic representation. Road maps, Rand McNally ® and GoogleMaps ® (not GoogleEarth) are examples of planimetric maps. Topographic Maps – Topographic maps show elevation or three-dimensional topography two dimensionally. Topographic maps use contour lines to show elevation. A chart refers to a nautical chart. Nautical charts are topographic maps in reverse. Rather than giving elevation, they provide equal levels of water depth. Topographic Maps Topographic maps show elevation or three-dimensional topography two dimensionally. Topographic maps use contour lines to show elevation.
    [Show full text]
  • Maps and Charts
    Name:______________________________________ Maps and Charts Lab He had bought a large map representing the sea, without the least vestige of land And the crew were much pleased when they found it to be, a map they could all understand - Lewis Carroll, The Hunting of the Snark Map Projections: All maps and charts produce some degree of distortion when transferring the Earth's spherical surface to a flat piece of paper or computer screen. The ways that we deal with this distortion give us various types of map projections. Depending on the type of projection used, there may be distortion of distance, direction, shape and/or area. One type of projection may distort distances but correctly maintain directions, whereas another type may distort shape but maintain correct area. The type of information we need from a map determines which type of projection we might use. Below are two common projections among the many that exist. Can you tell what sort of distortion occurs with each projection? 1 Map Locations The latitude-longitude system is the standard system that we use to locate places on the Earth’s surface. The system uses a grid of intersecting east-west (latitude) and north-south (longitude) lines. Any point on Earth can be identified by the intersection of a line of latitude and a line of longitude. Lines of latitude: • also called “parallels” • equator = 0° latitude • increase N and S of the equator • range 0° to 90°N or 90°S Lines of longitude: • also called “meridians” • Prime Meridian = 0° longitude • increase E and W of the P.M.
    [Show full text]
  • Bibliographical Index
    Bibliographical Index BIBLIOGRAPHICAL ACCESS TO THIS VOLUME Bacon, Roger. Opus Majus. 305, 322, 345 Basil, Saint. Homilies. 328 Three modes of access to bibliographical information are used Bede, the Venerable. De natura rerum. 137 in this volume: the footnotes; the bibliographies; and the Bib­ ---. De temporum ratione. 321 liographical Index. The footnotes provide the full form of a reference the first Cassiodorus. Institutiones divinarum et saecularium time it is cited in each chapter with short-title versions in litterarum. 172, 255, 259, 261 subsequent citations. In each of the short-title references, the Cato the Elder. Origines. 205 note number of the fully cited work is given in parentheses. Censorinus. De die natalie 255 The bibliographies following each chapter provide a selec­ Chaucer, Geoffrey. Prologue to the Canterbury Tales. 387 tive list of major books and articles relevant to its subject Cicero. Arataea (translation of Aratus's versification of matter. Eudoxus's Phaenomena). 143 The Bibliographical Index comprises a complete list, ar­ ---. Letters to Atticus. 255 ranged alphabetically by author's name, of all works cited in ---. De natura deorum. 160,168 the footnotes. Numbers in bold type indicate the pages on --. The Republic. 159, 160, 255 which references to these works can be found. This index is ---. Tusculan Disputations. 160 divided into two parts. The first part identifies the texts of Cleomedes. De motu circulari. 152, 154, 169 classical and medieval authors. The second part lists the mod­ Cosmas Indicopleustes. Christian Topography. 143, 144, ern literature. 261 Ctesias of Cnidus. Indica. 149 TEXTS OF CLASSICAL AND MEDIEVAL ---. Persica. 149 AUTHORS Dicuil.
    [Show full text]
  • U.S. Coast Guard Auxiliary Nautical Chart Updating Training Guide
    ` U.S. Coast Guard Auxiliary Nautical Chart Updating Training Guide National Ocean Service Office of Coast Survey Chart Updating Training Guide Ver. 2.4 2016 1 Table of Contents What is New - 3 Plotting (Chart Sections) - 30 Introduction to Chartplotter and GPS Navigation Software -31 Nautical Charts and Coast Pilot - 4 Using the Raster Navigational Charts Google Objective - 4 Earth Tool – 31 Background - 4 Introduction to NOAA Nautical Discrepancy Projections – 5 Report System – 32 Latitude and Longitude Scales - 6 Nautical Chart Feature Corrections – 32 Scales - 6 Coast Pilot Items – 33 Horizontal Datum – 7 Nautical Features Report – 34 Vertical Datum - 8 Instructions – 35 Depths Used on Nautical Charts- 8 Coast Pilot Report – 38 Traditional Paper Nautical Charts – 8 Instructions – 39 Chart Title and Information Block – 9 Reporting of Particular Feature Types - 41 Color Used on Nautical Charts – 9 NOAA’s Nautical Discrepancy Report System Lettering Styles – 10 – 42 Chart Depths – 10 Create a New Report – 43 Chart Edition – 10 Charting Action – 48 Updated Charts – 11 USACE Chart Discrepancy Reporting System - Nautical Chart Catalogs – 11 49 US Coast Pilot – 12 Chart Update AUXDATA Submittals - 52 US Coast Pilot Updates – 12 Individual’s duty for the patrol - 52 Bearings in the Coast Pilot – 12 Currents in the Coast Pilot – 13 Appendices Introduction to Nautical Chart Updating- 13 1. Responsible/Knowledgeable Sources, Objectives – 13 Reportable Chart Features -53 Background – 13 2. Difference Between RNCs and ENCs, Tools and Equipment useful in Print-on-Demand Paper Charts, PDF Chart Updating -14 Nautical Charts, Chart Updates (LNM Obtaining Information from Knowledgeable and NM Corrections) and Sources - 18 BookletCharts - 67 How to determine if an object is chartable – 18 3.
    [Show full text]
  • Scale NOAA Nautical Chart for Small Boaters When Possible, Use the Full-Size NOAA Chart for Navigation
    BookletChart™ Cumberland Head to Four Brothers Islands NOAA Chart 14782 A reduced-scale NOAA nautical chart for small boaters When possible, use the full-size NOAA chart for navigation. Included Area Published by the A special anchorage is on the west side of the lake in Deep Bay. (See 33 CFR 110.1 and 110.8(i), chapter 2, for limits and regulations.) National Oceanic and Atmospheric Administration Channels.–The south 37 miles of Lake Champlain, from Whitehall north National Ocean Service to Crown Point (44°01.8'N., 73°25.8'W.), is a narrow arm. The south 13 Office of Coast Survey miles of this arm, from Whitehall north to Benson Landing, is filled with a marshy flat traversed by a narrow channel of open water. A Federal www.NauticalCharts.NOAA.gov project provides for a 12-foot channel through this reach. In September 888-990-NOAA 2008, the controlling depths in the channel were 2 feet (7½ feet at midchannel) to Benson Landing. Above Benson Landing, natural deep What are Nautical Charts? water is available to Crown Point. The entire narrows, from Whitehall to Crown Point is well marked by lights and buoys. Nautical charts are a fundamental tool of marine navigation. They show North from Crown Point for about 75 miles to Rouses Point, Lake water depths, obstructions, buoys, other aids to navigation, and much Champlain is deep and wide. Prominent points and shoals throughout more. The information is shown in a way that promotes safe and the lake are marked by lights and buoys. efficient navigation.
    [Show full text]
  • Cartographic and Geospatial Materials
    LIBRARY OF CONGRESS COLLECTIONS POLICY STATEMENTS ±² Collections Policy Statement Index Cartographic and Geospatial Materials This document consolidates and replaces the former Maps, Atlases, and Remote Sensing Images Collections Policy Statement and Digital Geographic Data Collections Policy Statement Contents I. Scope II. Research Strengths III. Collecting Policy IV. Acquisitions Sources: Current and Future V. Collecting Levels: (Class G1000-G9980) I. Scope This Collections Policy Statement deals with analog geospatial resources presented graphically in the form of maps1, atlases, globes, charts (aeronautical and hydrographic), three-dimensional models, and aerial photography and remote sensing images; and digital geospatial data2 or spatially referenced data in the form of vector and raster representations, relational databases that incorporate common geographic features as attributes, remotely sensed digital imagery, software for the creation, retrieval, analysis and display of geospatial data, and web sites. For treatment of cartography as a subject, see the Geography and Cartography Collections Policy Statement. The majority of the Library's cartographic and geospatial materials (Library of Congress Classification Schedule G1000-G9980) is housed in the Geography and Map Division. Analog cartographic materials often complement or supplement textual works and may appear in the Library's other format or subject collection areas. In an evolving information society, cartographic representations of geographic data and geo-referenced content
    [Show full text]
  • Arnaud-Geography2014.Pdf
    CHAPTER 3 ANCIENT MARINERS BETWEEN EXPERIENCE AND COMMON SENSE GEOGRAPHY Pascal Arnaud Université Lyon 2 Abstract Although no first-hand information from ancient mariners have been preserved, their legacy to classical Greek geography has been so important that it is still pos- sible to recognise the structural impact of the material gathered from their implicit knowledge upon the patterns of presentation of space. The kind of tacit knowledge they had acquired appears very similar to that of the later Micronesians, studied by Hutchins. It was based upon durations rather than distances, and upon an original perception of orientations and directions. Thanks to that knowledge, based upon the repetition of experience through generations and apprenticeship, they were able to sail the blue sea without maps or instruments. This paper will address the issue whether – or within which limits – the mental construction of limited linear sec- tions of space may have opened the way to the construction of some coherent pre- sentation of space, a mental map in the fullest sense. In a well-known paragraph, Strabo1 establishes the direction and length of the passage between Rhodes and Alexandria and balances Eratosthenes’ calculations with ancient mariners’ experience: “The passage between Rhodes and Alexandria by north wind is about 4000 stadia; sailing along the coasts is twice this distance. Eratosthenes says that, this distance is the mere mariners’ conjecture of some, while others avow distinctly that it amounts to 5000 stadia; he himself, from observations of the shadows indicated by the gnomon, calculates it at 3750.” ‘Mariners’ were often scorned by ancient writers, when they were authors of travel narratives, but used to be considered as a main piece of evidence, when they were ano- nymous and a consensus came into being from a long-lasting verified experience of 1 2.5.24, C 168–169 = Erat.
    [Show full text]
  • Electronic Navigational Charts: International Standards and Map Projections
    Journal of Marine Science and Engineering Article Electronic Navigational Charts: International Standards and Map Projections Athanasios Palikaris 1,* and Athanasios K. Mavraeidopoulos 1,2 1 Hellenic Naval Academy, Navigation and Sea Sciences Laboratory, 18539 Pireas, Greece; [email protected] 2 National and Kapodistrian University of Athens, Remote Sensing Laboratory, 157 84 Athens, Greece * Correspondence: [email protected] Received: 4 March 2020; Accepted: 31 March 2020; Published: 3 April 2020 Abstract: Electronic navigational charts (ENCs) are geospatial databases, compiled for the operational use of Electronic Chart Display and Information systems (ECDIS) according to strict technical specifications of the International Hydrographic Organization (IHO). ECDIS is a GIS system designed for marine navigation according to the relevant standards of the International Maritime Organization (IMO). The international standards for ENCs and ECDIS, issued by the IHO and IMO, cover many aspects of the portrayal of ENCs in ECDIS but do not specify or recommend map projections. Consequently, in some cases, the unjustified employment of map projections by the manufacturers has caused certain functional drawbacks and inadequacies. This article reviews, evaluates and supplements the results of earlier studies on the selection of map projections for the depiction of ENCs in ECDIS and proposes a reasonable set of suitable projections with pertinent selection/implementation rules. These proposals took into consideration that ECDIS users (navigators) are
    [Show full text]
  • Nautical Charts, Texts, and Transmission: the Case of Conte Di Ottomano Freducci and Fra Mauro
    Nautical Charts, Texts, and Transmission: The Case of Conte di Ottomano Freducci and Fra Mauro Chet Van Duzer Contents Introduction 2 Conte di Ottomano Freducci and his Charts 4 Freducci and Fra Mauro 19 Freducci’s Chart, British Library, Add. MS. 11548 26 Transcription, Translation, and Commentary on the Legends 30 Legend 1 – Mauritania 30 Legend 2 – Mansa Musa and Guinea 32 Legend 3 – The Atlas Mountains 37 Legend 4 – The King of Nubia 38 Legend 5 – The Sultan of Babylon (Cairo) 40 Legend 6 – The Red Sea 42 Legend 7 – Mount Sinai 44 Legend 8 – Turkey 45 Legend 9 – The King of the Tartars 48 Legend 10 – Russia 53 Legend 11 – The Baltic Sea 55 Legend 12 – Scotland 56 Legend 13 – England 58 Legend 14 – The Island of Bra 60 Legend 15 – Ireland 62 Conclusions 64 1 eBLJ 2017, Article 6 Nautical Charts, Texts, and Transmission: The Case of Conte di Ottomano Freducci and Fra Mauro Introduction The majority of medieval and Renaissance nautical charts do not have legends describing sovereigns, peoples, or geographical features.1 These legends, like painted images of cities, sea monsters, ships, and sovereigns, were superfluous for charts to be used for navigation, and were extra-cost elements reserved for luxury charts to be owned and displayed by royalty or nobles. When descriptive legends do appear on nautical charts, they are generally quite similar from one cartographer to another, from one language to another (Latin, Catalan, Italian), and even across the centuries: there are some legends on early sixteenth-century nautical charts which are very similar indeed to the corresponding legends on late fourteenth-century charts.
    [Show full text]
  • A Short Course on Nautical Charts and Basic Plotting for the Recreational Boater
    A Short Course on Nautical Charts and Basic Plotting For the Recreational Boater Gary C. Kessler [email protected] https://scuba.garykessler.net Version 8.3a 26 August 2021 Ó Gary C. Kessler, 2012-2021 Table of Contents List of Figures ................................................................................................................................ iii Introduction ........................................................................................................................... 1 Part 1. Nautical Charts and Other Resources ........................................................................... 3 1.1. Purpose and Role of Nautical Charts ............................................................................... 3 1.1.1. Types of Charts ..................................................................................................... 3 1.1.2. Obtaining Charts ................................................................................................... 4 1.2. Supplementary Resources ............................................................................................... 6 1.2.1. Chart No. 1 ............................................................................................................ 6 1.2.2. U.S. Coast Pilot® .................................................................................................... 7 1.2.3. USCG Light List ...................................................................................................... 9 1.2.4. Notice to Mariners .............................................................................................
    [Show full text]
  • Renaissance Chart Tradition in the Mediterranean Corradino Astengo
    7 • The Renaissance Chart Tradition in the Mediterranean Corradino Astengo Introduction coast, and thus sailing them required special techniques and capacities—as Juan de Escalante de Mendoza recog- Medieval nautical charts were adequate for the needs of nized when he distinguished between sailors plotting the navigators of the day, who sailed the Atlantic and courses for coastlines (de costa y derrota) and those for Mediterranean coasts of Europe along well-established deep seas (de altura y escuadría), each group with their routes that were in part determined by the nature of local own skills and aptitudes.5 winds and currents and never led to ships’ losing sight of For more than two centuries the large cities and smaller land for more than two or three days.1 Yet in addition to ports of the Mediterranean continued the medieval tradi- being important working tools, these charts were also the tion of producing manuscript portolan charts and atlases documents that recorded the first achievements of At- organized around the distribution of wind rhumbs.6 lantic exploration, indicating newly discovered archipela- These charts were generally produced in small family gos and the gradually emerging features of the coast of workshops; the traditional art of making charts and im- Africa. Ultimately, the conquest of the oceans made nav- ages for navigation was handed down from generation to igation by the stars a necessity, and thus indications of lat- itude—along with the equator and the Tropics—were Abbreviations used in this chapter include: Carte da navigar for Su- added to the old rhumb line charts, gradually transform- sanna Biadene, ed., Carte da navigar: Portolani e carte nautiche del ing them into flat gridded charts that, even though non- Museo Correr, 1318–1732 (Venice: Marsilio Editori, 1990).
    [Show full text]
  • Dry Tortugas NOAA Chart 11438
    BookletChart™ Dry Tortugas NOAA Chart 11438 A reduced-scale NOAA nautical chart for small boaters When possible, use the full-size NOAA chart for navigation. Published by the Garden Key is the site of historic Fort Jefferson National Monument, a hexagonal structure with walls 425 feet long rising from a surrounding National Oceanic and Atmospheric Administration moat. The fortress, once a military prison, is now a government National Ocean Service reservation administered by the National Park Service. An abandoned Office of Coast Survey lighthouse, 67 feet high, is behind the SE bastion. A fixed white light, visible at least 8 miles, is displayed at night from the tower by the www.NauticalCharts.NOAA.gov National Park Service. Garden Key and the surrounding waters of the Dry 888-990-NOAA Tortugas are subject to rules and regulations prescribed by the Secretary of the Interior. Commercial fishing is prohibited within these waters. What are Nautical Charts? The S and N of the three wharves on the E side of the key are in ruins. The center wharf, off the SE front of the fort, is in good condition, with Nautical charts are a fundamental tool of marine navigation. They show 16 to 22 feet alongside. No fuel, provisions, or water are available. water depths, obstructions, buoys, other aids to navigation, and much Loggerhead Key, the other of the two principal keys in the Dry Tortugas, more. The information is shown in a way that promotes safe and is 2.5 miles W of Garden Key.Dry Tortugas Light (24°38'00"N., efficient navigation.
    [Show full text]