GB 15702-1995 Technical Specifications for Electronic Navigational Charts

This standard specifies the principles and methods for producing electronic nautical charts, the contents that electronic nautical charts should have, and the basic requirements for electronic nautical chart application systems when using electronic nautical charts. This standard is applicable to the production and use of electronic nautical charts, and can also be used as a reference for other computer systems when using electronic nautical charts. GB 15702-1995 Technical Specification for Electronic Navigational Charts GB15702-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Technical Specifications for Electronic Charts
Specifications for electronic chartsGB 15702-1995
This standard adopts the International Hydrographic Organization (IHO) S-52 (SPECIFICATIONS FOR CHART CONTENT AND DISPLAY ASPECTS OF ECDIS, 3rd Edition, October 1993).
1 Subject Content and Scope of Application
This standard specifies the principles and methods for producing electronic charts, the contents that electronic charts should have, and the basic requirements for electronic chart application systems when using electronic charts.
This standard is applicable to the production and use of electronic charts, and can also be used as a reference for other computer systems when using electronic charts. 2 Reference Standards
GB12317 Chart Format
GB12318 Specification for Nautical Chart Compilation
3 Terms
3.1 Electronic Chart, ECA chart that can be identified and processed by an electronic computer and attached to a certain carrier, represented by digital information, mainly describing the geographical elements of the sea area and navigation elements.
3.2 Electronic Chart Display and Information System, ECDISA marine automation system that centrally processes chart information, ship position information, radar information, and ship dynamic parameters under the control of a dedicated computer, and comprehensively presents the navigation situation with graphics, text, and sound. It consists of chart data files, control display equipment, external sensors, and dedicated software. Its basic functions are to display the sea area situation for sailors, provide navigation information, assist sailors in planning routes, plot real-time tracks, and monitor navigation conditions. It is equivalent to a paper chart in terms of chart display. 3.3 Electronic Chart System, ECS is a ship system used to display charts and tracks. It is not equivalent to paper charts in chart display. It should be used in conjunction with paper charts in navigation.
3.4 ​​Electronic Chart Application System, ECAS is an application system that uses electronic charts for navigation. It is a general term for 3.2, 3.3 or other systems that use electronic charts. When electronic charts are not equipped, it is referred to as electronic chart equipment.
3.5 Default display defaultdisplay
Also known as standard display or required display. It is a mode of displaying chart contents in layers according to importance. It means that after the electronic chart application system is started, the chart contents related to navigation safety are displayed without intervention. During normal navigation, this display mode is usually maintained. 3.6 True motion display True motion display refers to the use of chart contents as a fixed reference to depict the movement of the ship's position and other moving targets (such as radar targets) on the earth's surface. Approved by the State Administration of Technical Supervision on September 6, 1995 578
Implementation on January 1, 1996
GB 15702—1995
3.7 Relative motion display Relative motion display refers to the use of the ship's position fixed near the center of the display screen as a reference to relatively move the chart and other moving targets. 3.8 North-up display North-up display refers to the display of chart information or radar information that is always consistent with the paper chart, with due north pointing to the top of the display. It is generally inconsistent with the direction of the landscape viewed from the bow. 3.9 Course-up display Course-up display refers to the display of chart information or radar information that is basically consistent with the actual course of the ship, pointing to the top of the display.
3.10 Own ship's safety contour refers to a specific depth contour on the nautical chart set by the ship owner that is adjacent to and deeper than the draft of the ship. 3.11 Pan
Graphics larger than the display window size move freely and without interruption within the display window, making it easier for observers to see the entire graph through the display window.
3.12 Layering
The process or result of dividing related elements into multiple wholes. One whole is a layer. If the lighthouse and the light quality are related, they are divided into the same layer as a whole.
3.13 Highlighting
A method used to emphasize dangerous objects or targets that deserve emphasis. The emphasized cartographic targets are displayed continuously in bright colors with varying brightness.
3.14 Latitude bar
The latitude scale on the meridians of the Mercator projection map, with one minute of latitude representing one nautical mile in real terms. 3.15 DX-9 format DX-9 format
Developed by the Committee on the Exchange of Digital Data CEDD under the International Hydrographic Organization, it is a data format used for encoding or exchanging digital cartographic data. It summarizes the sequential mode and the chain node mode, and the element coding system used is the cartographic target classification of the International Hydrographic Organization. 3.16 Paper chart
A chart with paper as the medium.
3.17 Digital chart
An ordered collection of spatial data represented by numbers, mainly describing the geographical information of the sea area and navigation information. Its application in navigation is equivalent to electronic charts.
4 General provisions
4.1 Electronic charts should have the same role as paper charts in ensuring navigation safety. 4.2 Electronic chart equipment manufacturers have the right to use the internal data format of their own system, but should ensure that they can accept the electronic chart products provided by the maritime book publishing department.
4.3 Electronic chart equipment manufacturers and users should not change the original electronic chart data provided by the publishing department, but can add and display graphic information obtained from other data sources. The added information should be clearly distinguished from the original electronic chart content. 4.4 The electronic chart application system should have the function of hierarchical selection when processing and displaying the content of electronic charts. In terms of the integrity and accuracy of navigation information, it should be ensured that the displayed charts have the same reliability as paper charts, and can perform normal chart operations. 4.5 The electronic chart application system should have a data verification method to check the integrity of the electronic charts provided by the navigation book publishing department to ensure safe use.
4.6 The electronic chart data encoding should use the minimum amount of data while ensuring that the accuracy of the chart is not reduced and the content is not reduced, so that the electronic chart application system can quickly and effectively perform chart retrieval, data processing, chart display and operation. 5 Basic regulations for cartography
5.1 Coordinate system
Domestic areas adopt the coordinate system uniformly stipulated by the state. Foreign areas adopt the 1984 World Geodetic Coordinate System (WGS-84) stipulated by the International Hydrographic Organization.
When the coordinate systems of the mapping data, electronic charts, and positioning systems are inconsistent, coordinate conversion should be performed in both the production of cartography and the use of charts. If conversion is not possible, prompt information should be marked when the chart is displayed. However, the marked ship position must be consistent with the displayed chart coordinate system. For scales less than 1:1 million, no conversion will be made. 5.2 Depth and elevation benchmark
5.2.1 Depth benchmark
a. The theoretical lowest tide level is used in the measurement area of ​​the coastal system of China. b. Other areas use a depth benchmark consistent with the mapping data and are marked in the data file for query when the chart is displayed. The unit of depth measurement is meter.
5.2.2 Height datum
a. The "1985 National Height Datum" is used along the coast of China. For islands and reefs far from the mainland, the local average sea level can be used. b. Other areas use elevation base projections consistent with the mapping data, and are stated in the data file for reference when the chart is displayed. The unit of elevation measurement is meter.
5.3 Projection
5.3.1 Charts with a scale of less than 1:20,000 use Mercator projection. Complete sets of nautical charts use a unified datum latitude, and discontinuous single maps use the middle latitude of the map as the datum latitude.
5.3.21: For maps with a scale of 20,000 or larger, plan views or Gauss-Krüger projections are used. 5.4 Scale
5.4.1 The selection of the scale for electronic chart making refers to GB12318 Section 4.2. For the scale range, see 7.3. 5.4.2 When two or more scales are displayed simultaneously on the electronic chart application system, in addition to framing the boundaries on the screen, the scales should also be indicated separately.
5.4.3 When the electronic chart application system displays the chart, the cartographic scale should generally be used. In special cases, the display can be enlarged or reduced, and the zoom factor is 0.5 to 3 times the cartographic scale. When zooming, a prompt message should be marked on the screen to remind the user. 5.4.4 When the electronic chart application system displays the chart, the analytical scale should be added. 1:80,000 and larger scales should be drawn with equally divided linear scales. The divisions are 0.1M, 0.5M, 1.0M, etc. When the scale is less than 1:80,000, a gradually increasing latitude scale should be drawn. The divisions are 5°, 10°, 20, etc.
5.5 Chart description
refers to the general description of the current chart. It shall include at least the following contents: a. Chart name:
chart number;
scale,
scope:
projection;
depth, height reference and its unit;
plane coordinate system:
publishing unit and date of publication;
data source and data quality,
cut-off date for correction of Notice to Mariners, year and item number of Notice to Mariners adopted on the chart;
k, magnetic deviation;
1. Safety depth of own ship.
5.6 Framing
GB 15702--1995
5.6.1 According to the needs of different levels of electronic chart equipment, there are two ways to divide electronic charts: a. Paper chart framing;
b. Regular unit framing.
5.6.2 When framing according to paper charts, the principle is the same as Article 4.5 of GB12318. However, the main map, spliced ​​map, and various sub-maps are not used, nor is the "broken map outline" representation method. 5.6.3 When framing according to regular units, the units are divided into two categories: a. The smallest division of the basic unit electronic chart is a geographical area with a longitude difference of 15°×latitude difference of 15'. b. The derived unit is a unit divided according to the purpose of navigation based on the basic unit. Its longitudinal and transverse dimensions must be integer multiples of the basic unit.
5.6.4 Unit size is divided into the following categories according to the electronic chart type: General chart (identifier A)
Near and far sea navigation chart (identifier B)
Coastal navigation chart (identifier C)
Strait and waterway chart (identifier D)
e. Harbor chart (identifier E)
Longitude difference 8°×latitude difference 8°
Longitude difference 4°×latitude difference 4°
Longitude difference 1°×latitude difference 1°|| tt||Longitude difference 30°×latitude difference 30°
Longitude difference 15°×latitude difference 15°
5.6.5 The basic unit division method is that from 90° south latitude to 90° north latitude, the latitude difference 15° is a row; from the 0° meridian, the longitude difference 15° from west to east is a column. The world is divided into 720×1440 units. 5.6.6 The elements located at the left or lower boundary of the unit belong to this unit, while the elements at the right or upper boundary belong to its adjacent unit. 5.67 Each bat map or each unit is an independent data set (group). 5.7 Sheet coding (map number)
5.7.1 The sheets are divided according to the method of 5.6.1 a, and the sheets are coded with eight alphanumeric characters. The first two digits are the identifier EC of the electronic chart, and the next five digits are the corresponding paper chart number of the same scale and range. The numbering principle is shown in Appendix A of GB12318. If the original paper chart is a main illustration, a mosaic chart, or a series of sub-charts, it should be split into several single-sheet charts, and the numbers 1, 2, 3*** should be added to the end of the chart number. Otherwise, the number 0 should be added.
If the paper chart originally numbered 13100 is made into a corresponding electronic chart, its code is EC131000. 5.7.2 The charts are divided into sheets in the manner b of 5.6.1, and the sheets are coded with eight digits of alphanumeric characters. The first digit is the category identifier of the electronic chart, see 5.6.4. The following seven digits are the digital code of the sheet unit. 5.7.3 The coding principle of the sheet unit is:
The first three digits are the latitude row number of the basic unit contained in the lower left corner of the unit. The range is 000-719. The last four digits are the longitude column number of the basic unit contained in the lower left corner of the unit. The range is 0000-1439. For example, if the unit range of a 1:1 million ocean navigation chart is: 30°N～34°N, 120°E～124°E, the first digit of the unit code is B. Because its lower left corner contains the basic unit:
30°00°N~30°15°N,120°00°E~～120°15°E. Therefore: row number = (90+30)×4=480, column number = 120×4=480. Therefore, the code of the ocean navigation chart unit is B4800480. 5.7.4 Regardless of the encoding method used, the code is the main name of the chart file. The file extension is the corresponding version number, represented by a three-digit code. The first edition is 000, the second edition is 001, and the third edition is 0025.8 Navigation parameters
When displaying electronic charts or performing chart operations, the following navigation parameters are used: a. Location
GB 15702-1995
is expressed in longitude and latitude, and is written in the same format as the usual navigation format, i.e. DDD°MM.mm, with the prefix being the abbreviation of longitude or latitude, and the suffix being the abbreviation of direction. The abbreviation table is:
For example, 121°12.21'E is Long.121°12.21'E. b. Depth
is in meters, with an accuracy of 0.1m.
c. Height
is in meters, with an accuracy of 1m.
d. Distance
is in nautical miles, with an accuracy of 0.01M.
is in knots, i.e. nautical miles/hour. The accuracy is 0.01kn. f. Angle
is written in the same way as a of this clause. 。 Counterclockwise is negative, clockwise is positive. The azimuth is calculated from the north. g. Time time
is in hours, minutes and seconds. It uses the 24-hour system and the format used by computer operating systems is HH:MM:SS.ss. For example, 11 hours, 28 minutes and 16.21 seconds is 11:28:16.21.
h. Date date
uses the format used by computer operating systems MM-DD-YYYY, such as June 12, 1993 is 06-12-1993. 5.9 Analysis and selection of mapping data
5.9.1 Sources of mapping data:
Control data include various control point result tables; sea survey data include water depth, coastline result maps, and obstacle detection list: b.
c. Map data include various nautical charts, topographic maps and image data, etc.; digital data include digital survey results or digital mapping results, such as published digital topographic maps or digital nautical charts, geodetic control point data files, etc.; other data include route guides, tide tables, navigation notices, radio beacon tables, geomagnetic field data, etc. 5.9.2 The principles for selecting basic data are: a. Data with strong timeliness and a scale greater than or equal to the mapping scale shall be given priority; b. Digital data with qualified quality shall be given priority; domestic areas shall use the latest version of nautical charts or survey data (digital or paper) as basic data, and others as supplementary data. Foreign areas should choose the latest nautical charts of the country where they are located as basic data. 5.10 Basic methods and requirements for digitization
5.10.1 To convert maps or nautical charts and text data into digital data that can be recognized by computers, digitization is required. 5.10.2 Digital entry should be done by computer-based scanning digitization or hand-held tracking digitization. 5.10.3 When scanning digitization, the scanner resolution should not be lower than 0.05mm×0.05mm per pixel (equivalent to 500 dots/inch). The scanned image should be automatically processed and edited by human-computer interaction to convert it into loss-making mapping data. 5.10.4 When hand-held tracking digitization is used, the digitizer resolution should not be lower than 0.025mm (equivalent to 1000 dots/inch). Figure 582
GB 157C2--1995
The point-to-point error of outline positioning should be less than 0.15mm; at least four outline corner points should be used for positioning, and deformation correction and error allocation should be made for the original paper image. 5.10.5 Relative to the original mapping data, the positioning accuracy of point symbols is 0.15mm, the positioning accuracy of line symbols is 0.2mm, the edge accuracy of surface filling is 0.3mm, and the position accuracy of water depth annotation is 0.3mm. 5.10.6 The digital software should have the ability to accept data from various data sources, and have a convenient user interface and flexible human-computer interactive editing methods.
5.11 Symbol and element coding system
5.11.1 Electronic nautical charts are displayed on color monitors and are a kind of video image. The representation of all elements on the charts should comply with GB12317 in principle. Since the resolution of color monitors is lower than that of paper charts, the size of electronic nautical chart symbols should be enlarged to 1.3 times the size of paper chart symbols.
5.11.2 The electronic nautical chart symbol library is an integral part of the electronic nautical chart and should be provided to the electronic nautical chart users by the publishing department along with the electronic nautical chart.
5.11.3 The electronic nautical chart symbol library should be extensible, allowing the electronic nautical chart equipment manufacturer to add its specific symbols. 5.11.4 The electronic nautical chart equipment should have a help function so that users can browse the electronic nautical chart diagrams at any time. 5.11.5 The electronic nautical chart element coding system should be consistent with the target classification stipulated by the International Hydrographic Organization and compatible with the digital map element attribute coding standard promulgated by my country. 5.12 Data carrier and data security and confidentiality
5.12.1 Electronic nautical chart data products should be issued in the form of data files. The file is recorded on a removable data carrier, such as: a. floppy disk
compact disc-read-only-RAM, CD-ROM) b.
movable hard disk
solid state disk (RAM/ROM disk) magnetic tape
other media
5.12.2 Regardless of the data carrier, the product packaging must be marked with the drawing number, drawing name, scope, scale, publishing unit, date, and notice correction date. When multiple drawings coexist on one data carrier, a drawing index map should be attached. 5.12.3 To ensure data security, users shall not change the original surveying and mapping data files. 5.12.4 To maintain confidentiality and copyright, the publishing department shall encrypt the electronic nautical chart data files with software or hardware, and users shall not copy them illegally.
6 Classification of electronic chart equipment
According to the use requirements of different types of ships and the performance/price ratio of the system, electronic chart equipment is divided into three levels: high, medium and low. 6.1 High-level system
The chart display and representation method should be completely equivalent to the paper chart, and the chart screen switching time on the screen is less than 5s. It can select and match radar information and track no less than 10 dynamic targets. It is equipped with three color displays (at least one with a resolution of 1600 pixels × 1280 lines or more), which can display the basic map, local enlarged map and text information, and response information respectively. The positioning method should be the integrated navigation of multiple sensors. It has the function of track recording and echoing. 6.2 Intermediate system
The displayed chart is basically similar to the paper chart. The chart screen switching time on the screen is less than 10s. It can superimpose radar information and track no less than two dynamic self-markers. Equipped with a color graphic display with a resolution of 1280 pixels × 1024 lines or more, which can display the basic map or partially open the window to display the enlarged map. Equipped with a character display, which can display text information and response information. The positioning method should be connected to at least two high-precision radio positioning devices. It has track recording and echoing functions. 6.3 Low-level system
The nautical charts it displays only include basic navigation elements and sea-land relations. The switching time of the nautical chart screen on the screen is less than 15s. The nautical chart graphics and conversation text are displayed in sections on a monochrome or color display with a resolution of 1024 pixels × 768 lines or more. The positioning method should be connected to at least one high-precision radio positioning device. It has simple track recording and echoing functions. 6.4 The hardware host computer of electronic nautical chart equipment at all levels should have the ability to simultaneously process multiple positioning methods, graphic displays and nautical chart operations of this system.
7 Data structure
7.1 Basic requirements
7.1.1 The data structure of electronic nautical charts should be easy to use in the following aspects: compatible with foreign electronic nautical chart data, convenient for international navigation and exchange; a.
b. Can be easily converted to the internal data format of the electronic nautical chart equipment manufacturer! c. Convenient for the end users of electronic nautical charts;
d, convenient for adding and modifying navigation notices and other navigation information. 7.1.2 The data structure of electronic nautical charts should be able to summarize several main structures of vector mapping methods and have the possibility of expansion. Data should be organized according to spatial data and attribute data, and the visible graphic expression form is defined by the electronic nautical chart symbol library. 7.1.3 The data structure of electronic nautical charts should have a certain degree of flexibility. It cannot limit the method of data collection, nor can it limit the optimization and improvement of the system by the manufacturer of electronic nautical chart equipment. 7.1.4 The data structure of electronic nautical charts should support the DX-90 standard specified by the International Hydrographic Organization in data exchange. 7.2 Electronic chart database and chart unit
7.2.1 The electronic chart database is established on the basis of the marine surveying and mapping database. 7.2.2 The electronic chart used by the electronic chart equipment is a subset of the electronic chart database. A paper chart range or an independent navigation area is a chart unit.
7.2.3 The reselected parts of adjacent chart units, or the elements in chart units of different scales in the same area should come from the same data source and have internal accuracy consistency.
7.3 Scale range of electronic charts
Electronic charts are divided into general charts, navigation charts, harbor charts and other charts. 7.3.1 General chart
The scale is generally 1:3 million and smaller. The chart should include a complete sea area, fully showing the geographical characteristics and navigation characteristics of the area, for users to make navigation plans and understand the regional overview. 7.3.2 Navigation chart
The chart is mainly used for ship navigation. According to the navigation area, it is divided into: a. Open sea navigation chart 1:1 million to 1:2.99 million scale; b. Inshore navigation chart
1.2 million to 1:99 square scale;
c. Coastal navigation chart 1:100,000 to 1:190,000 scale d. Strait waterway chart
larger than 1:100,000 scale.
7.3.3 Harbor chart
The chart mainly depicts harbors, anchorages, access channels and harbor facilities. It is mainly used for ships to enter and exit harbors, anchorages and manage ports. The scale depends on the size of the harbor, generally 1:10,000 to 1:50,000, and a smaller scale can be used in special cases. 7.3.4 Other chartswwW.bzxz.Net
Charts used for special purposes, such as military command, engineering operations, etc. The scale is unlimited and is designed according to specific requirements. 7.3.51: Charts with a scale of 100,000 or less are scaled in steps of 10,000. Charts with a scale greater than 1:100,000 are scaled in steps of 5,000.
7.4 Data density and data integration
7.4.1 The data density of a chart unit should be as small as possible while ensuring that the electronic chart graphics are not distorted. No discarded data is allowed, and reasonable margins are allowed. For lines generated by flow or curve interpolation, the distance between two adjacent points on the chart should be 0.3-3.0 mm.
7.4.2 When making electronic charts, the principle of making large-scale charts first and small-scale charts later should be followed. When a small-scale map contains a large-scale map range, the data within the range should be selectively converted from the large-scale map to the small-scale map using data integration software, and the quality of automatic integration should be further improved by human-computer interaction. 7.4.3 The requirements for data integration are the same as those for paper chart compilation (see Chapter 7 of GB12318). 7.4.4 The data files generated by the data integration method cannot be separated, overlapped or crossed on the adjacent elements of adjacent units, and must match the boundaries.
7.5 Data partitioning and element identification
7.5.1 When making or using electronic charts, the internal data structure should be partitioned to speed up processing. 7.5.2 A map or a map unit is a (group) data file, which includes at least three data partitions, namely the control area, index area, and data area.
The control area is the overall control parameter of a map. The index area is a set of keywords for retrieving an element. The data area is the data entity of the element.
7.5.3 In order to quickly identify elements and improve display speed, the element index should at least include the following: a. The location of the address element in the data area;
b. Type, which is the identifier of the element type such as point, line, surface or text; c. Feature code, auxiliary code, which is the unique code specific to each element. The auxiliary code can be used for further subdivision of the element or drawing control parameters;
Priority, which is the priority level during display processing. The default displayed element is the highest level. 7.6 Priority and hierarchy
7.6.1 Data processed by electronic chart equipment, such as chart information, radar information, and other sensor data, must be managed in layers according to navigation requirements.
7.6.2 The purpose of layered management is to determine the display priority, to ensure that electronic chart users can clearly see the content related to navigation safety and quickly find the target they are concerned about. Several elements are allowed in one layer, and multiple layers of information are allowed in one level. One element can only belong to a specific layer, and ambiguity is not allowed. 7.6.3 The order of stratification and priority is as follows: 1. Prompt information of electronic nautical charts (warnings when coordinate system and depth reference are changed, prompts when the display screen scale is greater than or less than the mapping scale, etc.);
navigation obstacles;
corrections to navigation notices;
warning and attention texts on original paper nautical charts, surface filling of sea areas, land or different depth layers; default display content specified in Article 8.4,
other contents of electronic nautical charts that should be displayed upon request; radar information;
graphic information marked by users;
graphic information marked by electronic nautical chart equipment manufacturers; surface areas marked by users;
1. Surface areas marked by electronic nautical chart equipment manufacturers. 585
8 Content and Display
8.1 The basic contents of electronic nautical charts include:
Control points, elevation points and land features, coasts and islands;
GB 15702—1995
Land features, water systems, roads, boundaries, bridges, culverts and pipelines: residential areas;
Ports and offshore facilities;
Dry beaches;
Water depth, depth contours and bottom quality;
Navigational obstacles;
Aids to navigation:
Freightways, anchorages and various sea area boundaries, submarine pipelines: currents and tides;
Scenery maps, viewing points and Magnetic variation content;
Various place names, proper names and explanatory notes; geographic coordinate grids and marks, graphic scales. In order to adapt to the characteristics of navigation using electronic charts, the following elements should be deleted from the current paper chart content: a.
Chart gallery and outline decoration elements:
Azimuth circles;
Various navigation grids (such as hyperbolic grids, arc grids): detailed land features;
Connection charts, data index charts.
8.2 Relationship between chart content and display level
The content of electronic charts should not be determined by the standard of individual electronic chart equipment, but should summarize the requirements of different equipment levels. Allow users of each level to select their own content. When displaying charts, electronic chart equipment of different levels should have some selection of elements on the chart. High-level and medium-level equipment should be able to display all the contents of the chart. In addition to the default content, low-level equipment should also be able to display depth contours, water depth, ocean currents, tides, major geographical names, land, aids to navigation and obstacles.
8.3 Supplementary information
Electronic charts should add some additional navigation information compared to paper charts, such as tide signals, navigation marks, navigation methods, navigation, etc., in text form. 8.4 Default display content
Electronic chart application systems should have the function of layered display. For safe navigation, the following chart content should always be displayed during navigation.
Dry beach;
Isolated dangerous objects:
Safety depth contour of the ship's draft (calculated by all water depth elements in the map for special depth): d.
Fixed or floating marine aids to navigation, channel boundaries:
Various channel separation lines (strips) of traffic separation system: Visible land beacons or obvious radar reflection signs; Prohibited or restricted areas;
Caution and warning instructions;
GB 15702—1995
k. Graphic scale (linear scale or gradually increasing latitude scale); F
Boundary of the same picture with different scales, m.
Depth and elevation units.
8.5 Non-default display content
Non-default display content in electronic nautical charts refers to all chart elements except those specified in Article 8.4. They should be able to be instantly selected and added to the default display content when requested by the user, and should not cover the default display content. 8.6 Elements and attributes
8.6.1 Attribute information is non-graphic information (digital, logical or character information) that further describes the classification, grading, quality and quantity characteristics of elements on the chart.
8.6.2 Elements may or may not have attribute information. Attribute information is only displayed when it is needed. When displaying attribute information, elements with the attribute must be displayed at the same time. 8.7 Basic requirements for displaying chart content
8.7.1 Electronic nautical chart equipment of any level must have the functions of layering, zooming, roaming and partial windowing when displaying charts. 8.7.2 When zooming in or out, the graphic scale should be marked and a warning message should be given. 8.7.3 When partial windowing is used, the screen occupied should not be the navigation area. 8.7.4 The track and instantaneous ship position shall be plotted on the background of the nautical chart. Both relative motion and true motion display modes are allowed. When the relative motion mode is used, the ship position shall always remain near the center of the screen, and the screen switching time shall be less than 1 second. When the true motion mode is used, the ship position shall move in the center window of the screen. The center window is rectangular, and the distance from its edge to the edge of the screen is 100 pixels. If the ship position exceeds the center window, the page shall be “automatically flipped” to keep the ship position in the center window. The screen switching time shall be less than 510.15s on high-level, medium-level and low-level devices respectively. 8.7.5 When displaying in layers, the content of the n+1 layer shall not cover the content before the “n” layer, that is, the subsequent layer shall not destroy the drawn layer. 8.7.6 Radar information shall be processed in the form of a transparent overlay layer, which can be turned on or off instantly. 8.7.7 Symbol flashing is used to emphasize the flashed element. Only one element is allowed to flash on one screen, such as the safe draft contour of the ship. 8.7.8 The entire nautical chart shall be viewed quickly when roaming. 8.8 Display and display unit
8.8.1 Display
Display as a graphic output device for displaying electronic charts can be: cathode ray tube display (CRT); liquid crystal display (LCD); plasma display (plasma screen); electronic light display (EL); other types of displays.
8.8.2 Display unit
The display unit of the display is pixel. Different displays have different dot pitches (such as 0.28mm, 0.31mm, etc.). Compared with paper charts, the uniform definition is 0.15mm.
8.9 Display orientation
Electronic charts are generally displayed in the north-up direction. In special cases, the heading-up direction can also be used. In the heading-up mode, all dot symbols and character abbreviations on the chart should be rotated to keep the individual symbols visible on the screen. At this time, the true north line should be marked on the screen.
8.10 Color
8.10.1 Color electronic charts should be displayed on high- and medium-level electronic chart equipment. The color scheme is basically the same as that of paper charts, and at least not less than the standard 16 colors. The colors used at dawn, dusk, daytime and night are allowed to be slightly different. 8.10.2 Color electronic charts or monochrome electronic charts can be displayed on low-level electronic chart equipment. When displayed in monochrome, the foreground is green and the background is black. After the land is colored, the upper line should be drawn with the background color. 8.10.3 Radar information should be displayed in orange on the transparent overlay. Each pixel on the transparent overlay is 2 bits. 8.10.4 The graphics marked on the chart operation should be in dark red (excluding the monochrome display mode of low-level electronic chart equipment) to distinguish them from the original electronic chart content.
8.11 Literature
The electronic charts in China's sea areas are in Chinese, and those in foreign areas are in English. English versions can be provided for foreign ships or electronic charts for international exchange.
Only one language is allowed in a chart unit (except for abbreviations specified in the diagram). 9 Production and acceptance of finished products
9.1 The computer-aided mapping equipment and system software used to produce electronic charts must be appraised by experts organized by the competent department and can only be put into production after passing the trial.
9.2 The whole process of electronic chart production must implement comprehensive quality management, and go through the following stages: a.
Market research and task assignment;
Digital operation preparation:
Digital recording and editing;
Review and acceptance of data master;
Organize operation documents,
Finished product replication:
Finished product inspection and packaging.
9.3 Market research and task assignment
Market research refers to the investigation and analysis of the users and demand of electronic charts by the competent department for electronic chart production, which is the basis for the assignment of production tasks.
The work results of this stage are the formation of a market analysis report and a task notice. The task notice should include the mapping area, scale, division, number, requirements, operation basis and completion deadline. 9.4 Digitalization work preparation
The main task of this stage is to collect, organize and analyze the mapping data of the area to be digitized according to the task notice, study the characteristics of the digitization work in this area, formulate guiding technical documents for the operation, and mark the reference map for digitization operation. The work results are operation instructions (chart calendar for single map, operation details for complete map), various marked reference maps and sorted digital attribute data tables. 9.5 Digital input editing
The main task of this stage is to collect data for each element of the electronic chart according to the operation instructions. During the collection, the requirements for the positioning of various elements are:
a. If the cartographic object depicted by the point element does not have a unique reference point, the positioning point is taken as the center of its smallest bounding rectangle. For control points with coordinate results, their precise coordinates are input: b If the linear element is not a single line and is not depicted to scale, it is positioned according to the center line. The boundary line should be coded clockwise so that the enclosed area is on the right side of the boundary's forward direction;
c. If there is no obvious boundary line on the original paper chart of the surface element (such as the dredging channel is not closed on the sea side), it is closed with a "masking line" of the same color as the surface element; d. For directional elements, the last positioning point indicates the direction. The operator should comprehensively check the entered data and modify it repeatedly until the results are submitted. The results are electronic chart data files and corresponding documents that can be reviewed and accepted by the superior department. 9.6 Review and Acceptance
The main task of this stage is for a dedicated person to conduct a comprehensive and systematic inspection and acceptance of the results of digital input and editing, including: 588
The correctness of the use of digital data;
b. Whether the drawing load is appropriate;
The accuracy and completeness of the data;
GB 157021995
The correctness of the data hierarchy division, the logical consistency of the data coding, d.
The completeness and accuracy of the correction of the navigation notice. e.
The review and acceptance adopts a three-level system, namely, proofreading by the proofreader, review by the responsible editor, and acceptance by the technical quality department of the next level. After each level of inspection, it will be returned to the operator for modification, and then re-checked until the acceptance is completed. The work result of this stage is the data master of the electronic chart. 9.7 Organize the operation documents
The main task of this stage is to organize and archive the contents filled in the chart calendar in each stage described in Articles 9.5 to 9.7 as one of the results of the digitization operation. The organized documents should be able to reflect the digitization operation process, the handling of difficult problems, the analysis and evaluation of the reliability and currentness of the data results in detail.
9.8 Finished product replication
Copying the formal electronic chart data master produced in the operation stage into a digital product for users is called finished product replication. An independent carrier can store one or one unit of electronic charts, or multiple or multiple units of electronic charts. However, the electronic charts of a region must be stored in a centralized manner. During the replication period, the newly received navigation notices must be checked and revised to maintain the currentness of the electronic charts. After replication, the sheet code of the electronic chart, the latest number of notice corrections, the number of copies, the operation time and the operator should be registered. 9.9 Inspection and packaging of finished products
For finished electronic charts, the data carrier and data quality must be inspected one by one on the electronic chart inspection equipment. Only qualified products can be packaged.
The inner packaging of the finished product is the label of the carrier, the content of which is shown in Article 5.12.2. The outer packaging of the finished product is generally a moisture-proof and anti-magnetic plastic box. The label is the same as the inner packaging, and the inspection date and inspection number are added. 10 Correction and revision
10.1 Purpose of correction
In order to maintain the timeliness of electronic charts and ensure navigation safety, chart corrections must be made. The electronic chart application system should provide users with means of chart correction.
10.2 Conditions for implementation of corrections
Chart corrections should not be made under navigation conditions, and should generally be completed once using special software when preparing for sailing. 10.3 Release of correction information
The nautical book publishing department has the responsibility to provide digital or written chart correction information for electronic charts. For the method of writing and issuing written Notices to Mariners, please refer to GB12320 Specifications for Writing Notices to Mariners 10.4 Sources of Correction Data
The sources of chart correction data are mainly:
Written Notices to Mariners published by nautical book publishing departments: a.
Radio navigation warnings issued by nautical book publishing departments and local port supervision authorities; b.
Port navigation warnings issued by local port supervision authorities; d. Navigation notices for rivers entering the sea issued by local navigation authorities; other Notices to Mariners data.
10.5 Methods of Correction
10.5.1 Minor Correction
According to the deadline for correction of the Notice to Mariners of the current chart, the correction content of the Notice to Mariners of each issue related to this chart is added later. The selection of content should be determined by the scale. The result of the correction is to generate a system electronic nautical chart, which will be used as the master for the next correction of the notice and the current navigation chart 5899 Inspection and packaging of finished products
For finished electronic charts, the data carrier and data quality must be inspected one by one on the electronic chart inspection equipment. Only qualified products can be packaged.
The inner packaging of the finished product is the label of the carrier, the content of which is shown in Article 5.12.2. The outer packaging of the finished product is generally a moisture-proof and anti-magnetic plastic box. The label is the same as the inner packaging, and the inspection date and inspection number are added. 10 Correction and revision
10.1 Purpose of correction
In order to maintain the timeliness of electronic charts and ensure navigation safety, chart corrections must be made. The electronic chart application system should provide users with means of chart correction.
10.2 Conditions for implementation of corrections
Chart corrections should not be made under navigation conditions, and should generally be completed once using special software when preparing for sailing. 10.3 Release of correction information
The nautical book publishing department has the responsibility to provide digital or written chart correction information for electronic charts. For the method of writing and issuing written Notices to Mariners, please refer to GB12320 Specifications for Writing Notices to Mariners 10.4 Sources of Correction Data
The sources of chart correction data are mainly:
Written Notices to Mariners published by nautical book publishing departments: a.
Radio navigation warnings issued by nautical book publishing departments and local port supervision authorities; b.
Port navigation warnings issued by local port supervision authorities; d. Navigation notices for rivers entering the sea issued by local navigation authorities; other Notices to Mariners data.
10.5 Methods of Correction
10.5.1 Minor Correction
According to the deadline for correction of the Notice to Mariners of the current chart, the correction content of the Notice to Mariners of each issue related to this chart is added later. The selection of content should be determined by the scale. The result of the correction is to generate a system electronic nautical chart, which will be used as the master for the next correction of the notice and the current navigation chart 5899 Inspection and packaging of finished products
For finished electronic charts, the data carrier and data quality must be inspected one by one on the electronic chart inspection equipment. Only qualified products can be packaged.
The inner packaging of the finished product is the label of the carrier, the content of which is shown in Article 5.12.2. The outer packaging of the finished product is generally a moisture-proof and anti-magnetic plastic box. The label is the same as the inner packaging, and the inspection date and inspection number are added. 10 Correction and revision
10.1 Purpose of correction
In order to maintain the timeliness of electronic charts and ensure navigation safety, chart corrections must be made. The electronic chart application system should provide users with means of chart correction.
10.2 Conditions for implementation of corrections
Chart corrections should not be made under navigation conditions, and should generally be completed once using special software when preparing for sailing. 10.3 Release of correction information
The nautical book publishing department has the responsibility to provide digital or written chart correction information for electronic charts. For the method of writing and issuing written Notices to Mariners, please refer to GB12320 Specifications for Writing Notices to Mariners 10.4 Sources of Correction Data
The sources of chart correction data are mainly:
Written Notices to Mariners published by nautical book publishing departments: a.
Radio navigation warnings issued by nautical book publishing departments and local port supervision authorities; b.
Port navigation warnings issued by local port supervision authorities; d. Navigation notices for rivers entering the sea issued by local navigation authorities; other Notices to Mariners data.
10.5 Methods of Correction
10.5.1 Minor Correction
According to the deadline for correction of the Notice to Mariners of the current chart, the correction content of the Notice to Mariners of each issue related to this chart is added later. The selection of content should be determined by the scale. The result of the correction is to generate a system electronic nautical chart, which will be used as the master for the next correction of the notice and the current navigation chart 589
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