Advent of modern cartography in nautical charting
|A nautical chart is a medium of information and tool for safe maritime navigation. It is the chief nautical instrument for ocean route planning and safe navigation. With the time not only the user’s requirements have increased, but also the advancement in the expertise in the field of nautical cartography has resulted in better product in the most useful way. With the advent of modern cartography, chart contents are stored in digital form as database offering flexibility of producing nautical charts at any chosen scale and projection without going through the process of redrawing. Computer aided cartography since the nautical cartographers realized computer as their tool, has matured to an interdisciplinary field of research by now.
Cartography is undergoing a period of rapid change as a result of the process and product of information revolution. GIS, GPS, Geosciences, Oceanographic studies and thematic mapping through remote sensing has taken their berth in place of traditional mapping. The 1980’s saw an accelerating pace of technological change as the computer found its way into all aspects of cartographic production.
Modern cartography is capable of generating data in static and dynamic modes for different environment also. As automated cartographic technique, it is highly useful to capture, store, retrieve and presentation of hydrographic and topographic data into both raster and vector mode
The specific characteristic of modern cartography is to integrate various thematic data with aid of GIS, and remote sensing into required format for decision makers and planners during production of nautical charts.
Cartography evolved through three stages, the pre historic stage (from evolution of man to 4th century BC), the medieval stage (4th to 5th century) and the modern stage. In the primitive stage, cartography meant lines and sketches on the rock, leaves, and animal skins with the help of fibers of coconut tree and seashells. The first map were made by people of Marshal Island (pacific) and were used a “ Portland charts” Greeks were pioneer in modern cartography, Anaximander (611 BC – 547 BC) draw first map of Greece with geographical information. Periplus Maric Erythroci is the manual of Erythracean Sea prepared by an unknown Roman merchant is a significant contribution of cartography. During the middle age, Arabian and British geographer contributed a lot of work in the field of cartography and Portolon maps were prepared with the help of compass.
The modern stage of cartography starts from 1500 AD with the works of Nicholous, Crab, Martin, Pedru, Renial etc. The modern technique in cartography includes models, aerial photographs, Photogrammetry Remote sensing data and GIS, which make the subject methodical and rational. It has also reduced the time involved in the production of a map and nautical charts.
Development in nautical charting
Indian nautical cartographer has a good knowledge of astronomy and it is probable that they had prepared route and navigational chart though no ancient maps exist in India. The Indian Naval Hydrographic Department (INHD) is one of the oldest hydrographic departments in the world deriving its origins from the earliest voyages of the Europeans into the Indian water.
The earliest compilation of nautical charts of the Indian Ocean and Indian coasts was date back to 1703. The Naval Hydrographic Department was established in 1954 and assumed the national responsibility for hydrographic surveys of Indian water and production of the navigational charts. The early chart was published in 1959 using the cartographic standardization contained in chart branch order. The earlier charts (pre-1966) were totally hand drawn. The introduction of photo type- setting machine for lettering (1967) and scribe for line work (1969), made dynamic change in appearance of the nautical chart.
The chart provides a complete coverage of the area to cater for mariners need. Since the navigational chart is used by International shipping, it is essential that the symbol and abbreviation used on chart are in standard format so that these can be understood the world over. The face of Indian charts is totally modernized after switching over to new fonts and styles on acquisition of new model of photo type setting machine (1973). The line work which was hand drawn was gradually replaced by scribing which resulted in mass scale modernization of Indian nautical charts Today, the nautical chart must respond to the fast changing requirement of navigators and other specialist users.
Following the impact of computer technology on cartography, the working group of International Cartographic Association defines modern cartography as “ A holistic representation and intellectual abstraction of geographical reality, intended to be communicated for a purpose or purposes, transferring relevant geographical data into an end product which is visual, digital or tactile’’. Now a day’s computer has influenced every aspect of manual and analytical cartography in both static and dynamic environment.
Ease in updating of existing chart and map is the key advantage of modern cartography. Updating of topographic and hydrographic details for nautical chart interacting by using high resolution satellite images and digital ortho photos, supplemented by field data collected using GPS and processed through coordinate geometry is now well established.
Cartographer is now beginning to exploit the tools and methods of the new interactive media, multimedia and animation to show spatial distribution over time and space for various charting purposes.
Computers have influenced every aspect of manual and analytical cartography. The first aspect is cost effectiveness. After initial investment in digitization and creation of database for base map/ chart, the updating and multipurpose chart production by adding value added layer to the base map is both time and cost effective. Various thematic maps and charts can be produced using digital cartography.
Element of modern cartography
The most important development for modern cartography was incorporation of microprocessors directly into the display device. Over time, more and more functions and capabilities have moved from the main computer and have been directly incorporated into the graphic terminal. The next logical development was the disconnection of graphic terminal from mainframe as standalone system, called workstation. Some of the known workstation are SUN, SPACE, DEC, ALPHA, HP, IBM, INTRGRAPH and Silicon graphic. The additional components are monitor, digitizer and scanner and output devices like pen plotter, raster plotter and image setter equipme
Modern cartography now overlaps with GIS more than over before. This is a result of building more and more cartographic capabilities into GIS and even into remote sensing system. Some of the well known software package which are used in cartographic work, are listed below.
EASI/PACE, Image Analyst, ERDAS imagine, Er Mapper, TNTMips
Geographic Information System
Geomedia Professional, SPAN, ARC/INFO, MGE, MapInfo, ILWIS, IDRIS, CARIS GIS
Computer aided drafting system
Auto Cad, Micro station, Arc Cad
ACE (from PCI Geomatic) Map composer (from ERDAS) Map publisher (from INTERGRAPH) Arc plot (from ESRI)
Relation between cartography, remote sensing and GIS
Cartography, Remote sensing and Geographic Information System together with Geodesy, Photogrammetry and Surveying are grouped under the mapping science. From review of definition of cartography, RS and GIS, it can be demonstrated that there is a considerable overlap. Depending on the definition selected either cartography or GIS can be interpreted as totally subsuming the activities that might be claimed by others. There are various models, which outline possible conceptual relationship among this field, out of which three models are discussed here.
Modern cartography as integrating tool
Today with arrival of satellite data, microprocessors and computer aided system i.e. GIS, We have modern cartography with various software (ARC/INFO, ERDAS, INTERGRAF, CARIS) which have been proved to integrate multimedia data layers into a required format and scale for better and faster charting practice. The recent development in modern cartography has proved their capabilities to produce nautical charts in analogue form and electronic navigational chart in the form of electronic navigational chart database (ENCDB) for requirement of safety and automated navigation. Preparation of chart involves the integration of various topographic and hydrographic source materials into a balanced and harmonic composition on a specified scale.
National Hydrographic Office, Dehradun, India, under ministry of defense (Navy), is the pioneer office to produce nautical charts for marine safety navigation. To achieve the faster production of chart, NHO has been provided with modern cartographic division to integrate different types of ocean and topographic data into a required scale and projection with the help of INTERGRAPH workstation.
Preparation of fresh compilation for nautical chart using original hydrographic and topographic data involves the digitization of various analogue data which is available in the form of survey fair sheet, toposheet, satellite imageries, tidal data, current data, sailing direction etc. on different scale and projection. The scope and purpose of modern cartographic section at NHO are as follow.
The work procedure for production of nautical chart, involves inputting of data (hard copy and digital), preprocessing, compilation/auto compilation of various charts, ENC generation and chart preparation. The whole workflow is classified into five main activities as follow.
Application in support of nautical charting
Nautical chart is a specialized map, which is a legal tool for marine navigational safety and research. It is specifically designed to meet the requirement of marine navigation showing depth of water, nature of bottom, elevation and configuration of coast, danger and aids to navigation. Modern cartographic tools are being increasingly used world over for ocean and land management application. Digital Photogrammetry and image processing of remote sensing data jointly meet the mapping requirement of coastal and hydrographic management application. In addition to this technology, tools for integrating various thematic data and generation of hydrographic database for paper and ENC chart production are now available with modern cartography.
Based on experience of other International hydrographic offices, National Hydrographic Office, Dehradun also expects to utilize modern cartographic tools for nautical charting in the following ways. (a) Modern cartographic tools are useful for the generation of paper chart database and electronic navigational chart database (ENCDB) to produce paper chart and ENC.
Further improvement in modern cartography with aid of information technology will provide valuable information to represent marine features such as pinnacle rock, wreck, navigational buoys, beacon etc. that are important in nautical charting for safety navigation.
Modern cartographic techniques are being increasingly used world over for ocean and land management application. It involves the integration of data from various sources i.e. satellite imageries, aerial photography, GPS data and so forth. Multimedia cartography is a very new domain and has yet been explored fully for interactive visualization. It has also good potentiality for application in nautical chart production. Modern cartography includes utilities for generation of map features, finishing, printing, and publishing of cartographic quality map/chart as is the requirement of a host of national survey agencies. The modern cartography in addition with information technology and GIS provides the various integrating tools, which enable to create topographic and hydrographic database for nautical chart production. It also provides the faster production of charts to meet the national requirement for safety of navigation. At National Hydrographic Office, automatic cartographic technique is capable for creating database and producing nautical chart as both i.e. paper charts and Electronic navigational charts. Thus generation of static, dynamic and interactive cartographic output has become essential for planning and development purpose using digital and multimedia cartographic methods.
1. Peter F. Fisher and Richard