Computer graphic symbolic expression method for sea chart object under IHO S-52 standard

Abstract

The invention relates to a chart object computer graphic symbol expression method under the IHO S-52 standard, and the method comprises the steps: collecting chart data based on a collection instruction; based on the IHO S-52 standard, object information is extracted from the sea chart data, the object information is classified into different object categories, and the object categories comprise lighthouses, buoys, sunken ships and reefs; on the basis of the object type, symbol features are output, and the symbol features comprise the shape, the color, the size and the frame style; writing an instruction for the symbol characteristics based on a vector symbol description language; drawing a symbol based on the instruction; converting the symbol into an XML format; outputting an XML (Extensible Markup Language) file, wherein the XML file comprises all symbols in an XML format; and executing element symbol rendering based on the XML file. The method has the effects of forming a uniform symbolic expression rule and standardizing a symbolic expression method in the IHO S-52 standard computer graphic display process.

Description

Technical Field

[0001] The present application relates to the field of computer application development, and in particular to a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard. Background Art

[0002] In the field of computer graphics, graphic data in different industries and fields are usually divided into basic data types such as points, lines, and surfaces. For example, in marine surveying and mapping, water depth, land, obstacles, etc. are all such data. When these different types of data are mixed and displayed on the graphics, it is difficult to intuitively identify the specific content represented by each graphic without distinguishing them by symbols. Therefore, in order to clearly distinguish these graphics, different colors, shapes, outlines, fillings, etc. need to be used to modify them. This process is called symbolic expression.

[0003] However, at present, most software developers draw graphic symbols based on their personal understanding of the reference standard drawing instructions, which leads to the inconsistency and arbitrariness of symbolic expression. Specifically, they need to convert the data of nautical chart objects into graphics visible on the screen. This process is inefficient and the results are inconsistent due to the lack of unified standards. Therefore, improvements are urgently needed to achieve more efficient symbol drawing and more unified expression. Summary of the invention

[0004] In order to form a unified symbolic expression rule and standardize the symbolic expression method in the computer graphics display process of the IHO S-52 standard, the present application provides a computer graphics symbol expression method for nautical chart objects under the IHO S-52 standard.

[0005] The first object of the invention of this application is achieved through the following technical solutions:

[0006] A method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard, comprising:

[0007] Collect chart data based on collection instructions;

[0008] Based on the IHO S-52 standard, extracting landmark information from the nautical chart data, and classifying the landmark information into different landmark categories, the landmark categories including lighthouses, buoys, shipwrecks, and reefs;

[0009] Outputting symbol features based on the object category, wherein the symbol features include shape, color, size, and border style;

[0010] Based on the vector symbol description language, write instructions for symbol features;

[0011] Based on the instructions, draw symbols;

[0012] Convert symbols to XML format;

[0013] Output an XML file, wherein the XML file includes all XML format symbols;

[0014] Perform feature symbol rendering based on XML files.

[0015] In a preferred embodiment, the step of writing instructions for symbol features based on a vector symbol description language includes:

[0016] The instruction consists of several fields;

[0017] The fields include object code, attribute combination, drawing instruction, display priority, radar priority, display classification, and display grouping.

[0018] In a preferred embodiment, converting the symbol into XML format includes:

[0019] Define the rules for symbol expression, including the color, shape, fill and outline of point, line and surface symbol types;

[0020] Each symbol corresponds to a symbol protocol in XML format, with the symbol as the root node, and each level of symbol layers is arranged under the root node;

[0021] The symbol layers at each level are organized in a covering order;

[0022] A single symbol layer is composed of a point symbol layer, a line symbol layer, and a surface symbol layer;

[0023] The layer list of each symbol is composed of individual symbol layers, grouped into the symbol base class;

[0024] Based on the symbol base class, convert the layer list of all symbols into XML format.

[0025] In a preferred embodiment, the element symbol rendering is performed based on the XML file, including:

[0026] Based on the symbol base class, the vector map renderer, and the data source, the element symbol rendering is performed, and the element symbol rendering includes single rendering, regular rendering, and classified rendering;

[0027] The element symbol rendering and the rendering registration class are mutually input.

[0028] In a preferred embodiment, the converting of the symbol into XML format further includes:

[0029] When the symbol is a dot symbol,

[0030] Define three symbol layers: basic point symbol layer, scalable vector graphic symbol layer and font icon symbol layer;

[0031] Based on the basic symbol layer, draw simple graphics based on continuous coordinates;

[0032] Based on the scalable vector graphics symbol layer, complex graphics can be displayed by overlaying SVG images as symbol layers;

[0033] Based on the font icon symbol layer, draw text, wherein the text includes static text and dynamic text;

[0034] Create point symbols by arranging and combining basic symbol layers, scalable vector graphics symbol layers, and font icon symbol layers based on a preset order.

[0035] In a preferred embodiment, the converting of the symbol into XML format further includes:

[0036] When the symbol is a line symbol,

[0037] Define two symbol layers: basic line symbol layer and marker line symbol layer;

[0038] Create simple line types based on the basic line symbol layer;

[0039] Based on the marker line symbol layer, point symbols are arranged according to specific rules to form a line type;

[0040] Based on the rules of point symbols, point symbols are nested inside the marker line symbol layer;

[0041] A complex line symbol is created by combining a basic line symbol layer and a marker line symbol layer, and parameters are set, including a dashed line interval, a point symbol interval, and an offset.

[0042] In a preferred embodiment, the converting of the symbol into XML format further includes:

[0043] When the symbol is a face symbol,

[0044] Define four symbol layers: basic fill symbol layer, centroid fill symbol layer, point pattern fill symbol layer, and line fill symbol layer;

[0045] Simple fill polygon symbol based on basic fill symbol layer;

[0046] Based on the point symbol rule, a single point symbol is used to represent the polygon symbol in the centroid fill symbol layer;

[0047] In the dot pattern fill symbol layer, the surface symbol is represented by regularly or randomly arranged dot symbols, and the dot is filled after the drawing position is determined;

[0048] In the line fill symbol layer, the line symbol position is determined by scanning the line, and the surface symbol is filled with the embedded line symbol;

[0049] Create complex surface symbols by overlaying different basic fill symbol layers, centroid fill symbol layers, point pattern fill symbol layers, and line fill symbol layers.

[0050] The above-mentioned second objective of the present application is achieved through the following technical solutions:

[0051] A computer device comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard are implemented.

[0052] The third objective of the present application is achieved through the following technical solutions:

[0053] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard.

[0054] In summary, the present application includes at least one of the following beneficial technical effects:

[0055] 1. According to the collection instructions, the task of collecting nautical chart data begins. According to the S-52 standard established by the International Hydrographic Organization (IHO), the collected nautical chart data is processed, and then the object information in the nautical chart data is identified and extracted. Object information refers to geographical features and information points that are critical to navigation safety. Finally, the object information is classified into different object categories, including lighthouses, buoys, shipwrecks, and reefs. According to the category of the object, the corresponding symbol features are determined and output. In order to apply the symbol features to specific objects, a series of instructions are written using the vector symbol description language. The vector symbol description language is a programming language used to define and describe symbol properties. It can accurately indicate how to draw and represent symbols on a graphical interface. The symbols are actually drawn according to the instructions. This process is part of graphics rendering, in which each instruction is used to guide how to accurately draw the shape, color, and other visual attributes of the symbol on the screen. Convert the already drawn symbols or the data structure related to the symbols into XML format. XML is a markup language used to store and transmit data. It defines the structure of data through tags, making the data easy to be parsed by machines and read by humans. An operation will be performed, that is, creating and saving an XML file. This XML file will contain all the data that needs to be recorded, which has been converted into a format that conforms to XML syntax and structure. This file can be used for subsequent data processing, exchange or archiving. It involves reading the data structure and content in the XML file, and then generating corresponding graphic symbols based on this data. This process includes parsing specific tags and attributes in the XML file, which define the style, position and other visual characteristics of the feature symbol, and then converting these definitions into graphic elements and accurately rendering them in the graphical user interface or printout to achieve visual representation of data and effective communication of information.

[0056] 2. The instructions are designed to contain multiple specific fields, each with its own unique function and meaning. Specifically, these fields include: object code (used to uniquely identify each object), attribute combination (defines the characteristics and attributes of the object), drawing instructions (instructions on how to draw the object), display priority (determines the order in which objects are displayed), radar priority (the display priority of objects in the radar system), display classification (classifies objects into different categories), and display grouping (displays objects in specific logical groups). The combination of these fields ensures that the system can accurately control the presentation of objects to meet specific display needs and user interaction requirements.

[0057] 3. Defines the rules for symbol expression, which cover the color, shape, fill and outline of point, line and surface symbol types, ensuring the consistency and standardization of symbols; points out that each symbol corresponds to a symbol protocol in XML format, which takes the symbol as the root node and sets different levels of symbol layers under the root node to represent the complexity of the symbol; explains that these symbol layers are organized in an overlapping order, which determines the visual superposition order of symbols; describes that a single symbol layer is composed of a point symbol layer, a line symbol layer and a surface symbol layer, so that the graphic features of the symbol can be fully represented; points out that the layer list of each symbol is composed of a single symbol layer, and these layers are grouped into a symbol base class, providing a structured framework for the symbol; finally, based on this symbol base class, the layer lists of all symbols are converted into XML format to facilitate data exchange and processing between different systems and platforms. This series of steps ensures that symbols can be accurately expressed and rendered in graphic information systems.

[0058] Step 4 involves using the symbol base class, vector map renderer, and data source to perform feature symbol rendering operations. This process includes three rendering methods: single rendering, rule rendering, and classified rendering. Single rendering may refer to the direct rendering of a single symbol, rule rendering renders symbols according to a predefined set of rules, and classified rendering renders symbols according to the classification attributes of the data. It illustrates that there is an interaction between the feature symbol rendering process and the rendering registration class, that is, the rendering operation needs to receive input (such as rendering rules or parameters) from the rendering registration class, and may also feed back the rendering results or status to the rendering registration class to ensure the flexibility and manageability of the rendering process. This mutual input relationship ensures the dynamics and accuracy of the rendering process, allowing symbols to be appropriately visually represented according to different data and conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a flowchart of an implementation of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard in the present application;

[0060] Figure 2 This is a flowchart of an implementation of S40 in an embodiment of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard of the present application;

[0061] Figure 3 This is a first implementation flow chart of S60 in an embodiment of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard of the present application;

[0062] Figure 4 This is a flowchart of implementation of S80 in an embodiment of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard of the present application;

[0063] Figure 5 This is a second implementation flow chart of S60 in an embodiment of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard of the present application;

[0064] Figure 6 This is a third implementation flow chart of S60 in an embodiment of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard of the present application;

[0065] Figure 7 This is a fourth implementation flow chart of S60 in an embodiment of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard of the present application;

[0066] Figure 8 This is a principle block diagram of a computer device of the present application. DETAILED DESCRIPTION

[0067] The following is combined with Figure 1-8 This application is described in further detail.

[0068] In one embodiment, if Figure 1 As shown, the present application discloses a method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard, which specifically includes the following:

[0069] S10: collecting chart data based on the collection instruction;

[0070] In this embodiment, the task of collecting the nautical chart data starts to be executed according to the collection instruction.

[0071] S20: extracting object information from the nautical chart data based on the IHO S-52 standard, and classifying the object information into different object categories, wherein the object categories include lighthouses, buoys, shipwrecks, and reefs;

[0072] In this embodiment, the collected nautical chart data is processed according to the S-52 standard established by the International Hydrographic Organization (IHO), and then the object information in the nautical chart data is identified and extracted. The object information refers to the geographical features and information points that are crucial to navigation safety. Finally, the object information is classified into different object categories, which include lighthouses, buoys, shipwrecks, and reefs.

[0073] S30: Based on the object category, output symbol features, the symbol features include shape, color, size, and border style;

[0074] In this embodiment, the corresponding symbol feature is determined and output according to the category of the object.

[0075] S40: Writing instructions for symbol features based on a vector symbol description language;

[0076] In this embodiment, in order to apply the symbol feature to a specific object, a series of instructions are written using a vector symbol description language, which is a programming language used to define and describe symbol attributes, and can accurately indicate how to draw and represent symbols on a graphical interface.

[0077] S50: drawing symbols based on the instructions;

[0078] In this embodiment, the symbol is actually drawn according to the instructions generated in step S40. This process is part of graphics rendering, in which each instruction is used to guide how to accurately draw the shape, color and other visual attributes of the symbol on the screen.

[0079] S60: convert the symbol into XML format;

[0080] In this embodiment, the drawn symbols or data structures related to the symbols are converted into XML format. XML is a markup language used to store and transmit data, which defines the structure of data through tags, making the data easy to be parsed by machines and read by humans.

[0081] S70: Output an XML file, wherein the XML file includes all XML format symbols;

[0082] In this embodiment, an operation will be performed, that is, creating and saving an XML file. This XML file will contain all the data that need to be recorded, which have been converted into a format that conforms to XML syntax and structure. This file can be used for subsequent data processing, exchange or archiving.

[0083] S80: Execute feature symbol rendering based on the XML file.

[0084] In this embodiment, it involves reading the data structure and content in the XML file, and then generating corresponding graphic symbols based on these data. This process includes parsing specific tags and attributes in the XML file, which define the style, position and other visual features of the element symbol, and then converting these definitions into graphic elements, and accurately rendering them in the graphical user interface or printout to achieve visual representation of data and effective communication of information.

[0085] Reference Figure 2 , S40, including:

[0086] S401: The instruction is composed of several fields;

[0087] S402: The fields include object code, attribute combination, drawing instruction, display priority, radar priority, display classification, and display grouping.

[0088] In this embodiment, the instruction is designed to include multiple specific fields, each of which has its own unique function and meaning. Specifically, these fields include: object code (used to uniquely identify each object), attribute combination (defining the characteristics and attributes of the object), drawing instructions (instructing how to draw the object), display priority (determining the order of objects when displayed), radar priority (the display priority of objects in the radar system), display classification (dividing objects into different categories), and display grouping (displaying objects according to specific logical groups). The combination of these fields ensures that the system can accurately control the presentation of objects to meet specific display requirements and user interaction requirements.

[0089] Reference Figure 3 , S60, including:

[0090] S601: define the rules for symbol expression, including the color, shape, fill and outline of point, line and surface symbol types;

[0091] S602: Each symbol corresponds to a symbol protocol in XML format, with the symbol as a root node, and symbol layers of various levels are arranged under the root node;

[0092] S603: The symbol layers at each level are organized in a covering order;

[0093] S604: A single symbol layer is composed of a point symbol layer, a line symbol layer, and a surface symbol layer;

[0094] S605: The layer list of each symbol is composed of a single symbol layer and is grouped into a symbol base class;

[0095] S606: Based on the symbol base class, convert the layer list of all symbols into XML format.

[0096] In this embodiment, S601 defines the rules for symbol expression, which cover the color, shape, fill and outline of point, line and surface symbol types, ensuring the consistency and standardization of symbols; S602 points out that each symbol corresponds to a symbol protocol in XML format, which takes the symbol as the root node and sets different levels of symbol layers under the root node to represent the complexity of the symbol; S603 explains that these symbol layers are organized in an overlapping order, which determines the visual superposition order of the symbols; S604 describes that a single symbol layer is composed of a point symbol layer, a line symbol layer and a surface symbol layer, so that the graphic features of the symbol can be fully represented; S605 points out that the layer list of each symbol is composed of a single symbol layer, and these layers are grouped into a symbol base class, providing a structured framework for the symbol; finally, S606 converts the layer lists of all symbols into XML format based on this symbol base class to facilitate data exchange and processing between different systems and platforms. This series of steps ensures that symbols can be accurately expressed and rendered in the graphic information system.

[0097] Reference Figure 4 , S80, including:

[0098] S801: Based on the symbol base class, the vector map renderer, and the data source, perform feature symbol rendering, wherein the feature symbol rendering includes single rendering, rule rendering, and classification rendering;

[0099] S802: The element symbol rendering and the rendering registration class are mutually input.

[0100] In this embodiment, step S801 involves using a symbol base class, a vector map renderer, and a data source to perform rendering operations on feature symbols. This process includes three rendering methods: single rendering, rule rendering, and classification rendering. Single rendering may refer to the direct rendering of a single symbol, rule rendering renders symbols according to a predefined set of rules, and classification rendering renders symbols according to the classification attributes of the data. S802 illustrates that there is an interaction between the feature symbol rendering process and the rendering registration class, that is, the rendering operation needs to receive input (such as rendering rules or parameters) from the rendering registration class, and may also feed back the rendering results or status to the rendering registration class to ensure the flexibility and manageability of the rendering process. This mutual input relationship ensures the dynamics and accuracy of the rendering process, allowing symbols to be appropriately visually represented according to different data and conditions.

[0101] Reference Figure 5 , S60, also includes:

[0102] SA1: When the symbol is a dot symbol,

[0103] SA2: defines three symbol layers: basic point symbol layer, scalable vector graphics symbol layer and font icon symbol layer;

[0104] SA3: Based on the basic symbol layer, draw simple graphics based on continuous coordinates;

[0105] SA4: Based on scalable vector graphics symbol layer, complex graphics can be displayed by overlaying SVG images as symbol layers;

[0106] SA5: Draw text based on the font icon symbol layer, where the text includes static text and dynamic text;

[0107] SA6: Create point symbols by arranging and combining basic symbol layers, scalable vector graphics symbol layers, and font icon symbol layers based on a preset order.

[0108] In this embodiment, SA1 indicates that the following sub-steps will apply when a point symbol is being processed. SA2 defines three different symbol layers: a basic point symbol layer for displaying basic point graphics, a scalable vector graphics (SVG) symbol layer for displaying more complex graphics, and a font icon symbol layer for displaying text content. SA3 explains how to draw simple continuous coordinate graphics based on the basic symbol layer, SA4 describes how to use SVG images as symbol layers to overlay and display complex graphics, and SA5 involves drawing static or dynamic text on the font icon symbol layer. SA6 is the last step of the entire process, which arranges and combines the basic symbol layer, SVG symbol layer, and font icon symbol layer in a preset order to create a complete point symbol. This point symbol not only contains basic graphic elements, but may also contain complex graphics and text information, making it highly recognizable and informative in maps or other visual representations.

[0109] Reference Figure 6 , S60, also includes:

[0110] SB1: When the symbol is a line symbol,

[0111] SB2: defines two symbol layers: basic line symbol layer and marker line symbol layer;

[0112] SB3: Create simple line types based on the basic line symbol layer;

[0113] SB4; Based on the marker line symbol layer, point symbols are arranged according to specific rules to form a line type;

[0114] SB5: Based on the rule of point symbols, point symbols are nested inside the marker line symbol layer;

[0115] SB6: Create a complex line symbol by combining the basic line symbol layer and the marker line symbol layer, and set parameters, including the interval between dashed and solid lines, the point symbol interval and the offset.

[0116] In this embodiment, SB2 defines two types of line symbol layers: the basic line symbol layer is used to draw the basic outline of the line, and the marker line symbol layer is used to add additional marks or patterns on the line. SB3 explains how to use the basic line symbol layer to create a simple line type. SB4 describes how to arrange point symbols according to specific rules in the marker line symbol layer to form a line type, and these point symbols can increase the visual expressiveness of the line. SB5 points out that point symbols can be nested inside the marker line symbol layer. These point symbols follow specific rules to further enrich the details and complexity of the line type. SB6 is the final combination step, which creates a complex line symbol by combining the basic line symbol layer and the marker line symbol layer, and allows the appearance of the line symbol to be customized by setting parameters (such as the interval between dashed and real lines, the interval between point symbols, and the offset), thereby achieving high customizability and diversity of line symbols.

[0117] Reference Figure 7 , S60, also includes:

[0118] SC1: When the symbol is a face symbol,

[0119] SC2: defines four symbol layers: basic fill symbol layer, centroid fill symbol layer, dot pattern fill symbol layer, and line fill symbol layer;

[0120] SC3: Based on the basic fill symbol layer, simple fill surface symbol;

[0121] SC4: Based on the point symbol rule, a single point symbol is used to represent the polygon symbol in the centroid fill symbol layer;

[0122] SC5: In the dot pattern fill symbol layer, the surface symbol is represented by regularly or randomly arranged dot symbols, and the dot is filled after the drawing position is determined;

[0123] SC6: In the line fill symbol layer, the line symbol position is determined by scanning the line, and the surface symbol is filled with the embedded line symbol;

[0124] SC7: Create complex polygon symbols by overlaying different basic fill symbol layers, centroid fill symbol layers, point pattern fill symbol layers, and line fill symbol layers.

[0125] In this embodiment, SC2 defines four different symbol layers: the basic fill symbol layer is used for simple color filling, the centroid fill symbol layer is used to place a single point symbol at the center point of the surface, the dot pattern fill symbol layer is used to fill the surface with regularly or randomly arranged dot symbols, and the line type fill symbol layer is used to fill the surface with line symbols. SC3 illustrates how to perform simple surface symbol filling based on the basic fill symbol layer. SC4 describes how to use a single point symbol to represent the entire surface symbol in the centroid fill symbol layer. SC5 explains how to represent surface symbols by regularly or randomly arranged point symbols in the dot pattern fill symbol layer, and perform dot filling after determining the drawing position. SC6 illustrates how to determine the position of line symbols by scanning lines in the line type fill symbol layer, and use these line symbols to fill the surface symbol. SC7 creates complex surface symbols by superimposing different fill symbol layers, including basic fill, centroid fill, dot pattern fill and line type fill, thereby providing rich visual expression and design flexibility.

[0126] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0127] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 8 As shown. The computer device includes a processor, a memory, a network interface and a database connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store point symbols, line symbols, and surface symbols. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a computer graphic symbol expression method for nautical chart objects under the IHO S-52 standard is implemented.

[0128] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard is implemented.

[0129] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard is implemented.

[0130] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0131] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

Claims

1. A method for expressing nautical chart features in computer graphic symbols under the IHO S-52 standard, characterized in that: include: Collect chart data based on collection instructions; Based on the IHO S-52 standard, extracting landmark information from the nautical chart data, and classifying the landmark information into different landmark categories, the landmark categories including lighthouses, buoys, shipwrecks, and reefs; Outputting symbol features based on the object category, wherein the symbol features include shape, color, size, and border style; Based on the vector symbol description language, write instructions for symbol features; Based on the instructions, draw symbols; Convert symbols to XML format; Output an XML file, wherein the XML file includes all XML format symbols; Perform feature symbol rendering based on XML files.

2. The method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard according to claim 1, characterized in that: The method of writing instructions for symbol features based on a vector symbol description language includes: The instruction consists of several fields; The fields include object code, attribute combination, drawing instruction, display priority, radar priority, display classification, and display grouping.

3. The method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard according to claim 1, characterized in that: The conversion of symbols into XML format includes: Define the rules for symbol expression, including the color, shape, fill and outline of point, line and surface symbol types; Each symbol corresponds to a symbol protocol in XML format, with the symbol as the root node, and each level of symbol layers is arranged under the root node; The symbol layers at each level are organized in a covering order; A single symbol layer is composed of a point symbol layer, a line symbol layer, and a surface symbol layer; The layer list of each symbol is composed of individual symbol layers, grouped into the symbol base class; Based on the symbol base class, convert the layer list of all symbols into XML format.

4. The method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard according to claim 1, characterized in that: The step of performing element symbol rendering based on the XML file includes: Based on the symbol base class, the vector map renderer, and the data source, the element symbol rendering is performed, and the element symbol rendering includes single rendering, regular rendering, and classified rendering; The element symbol rendering and the rendering registration class are mutually input.

5. The method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard according to claim 1, characterized in that: The converting of the symbol into XML format further includes: When the symbol is a dot symbol, Define three symbol layers: basic point symbol layer, scalable vector graphic symbol layer and font icon symbol layer; Based on the basic symbol layer, draw simple graphics based on continuous coordinates; Based on the scalable vector graphics symbol layer, complex graphics can be displayed by overlaying SVG images as symbol layers; Based on the font icon symbol layer, draw text, wherein the text includes static text and dynamic text; Create point symbols by arranging and combining basic symbol layers, scalable vector graphics symbol layers, and font icon symbol layers based on a preset order.

6. The method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard according to claim 1, characterized in that: The converting of the symbol into XML format further includes: When the symbol is a line symbol, Define two symbol layers: basic line symbol layer and marker line symbol layer; Create simple line types based on the basic line symbol layer; Based on the marker line symbol layer, point symbols are arranged according to specific rules to form a line type; Based on the rules of point symbols, point symbols are nested inside the marker line symbol layer; A complex line symbol is created by combining a basic line symbol layer and a marker line symbol layer, and parameters are set, including a dashed line interval, a point symbol interval, and an offset.

7. The method for expressing nautical chart features by computer graphic symbols under the IHO S-52 standard according to claim 1, characterized in that: The converting of the symbol into XML format further includes: When the symbol is a face symbol, Define four symbol layers: basic fill symbol layer, centroid fill symbol layer, point pattern fill symbol layer, and line fill symbol layer; Simple fill polygon symbol based on basic fill symbol layer; Based on the point symbol rule, a single point symbol is used to represent the polygon symbol in the centroid fill symbol layer; In the dot pattern fill symbol layer, the surface symbol is represented by regularly or randomly arranged dot symbols, and the dot is filled after the drawing position is determined; In the line fill symbol layer, the line symbol position is determined by scanning the line, and the surface symbol is filled with the embedded line symbol; Create complex surface symbols by overlaying different basic fill symbol layers, centroid fill symbol layers, point pattern fill symbol layers, and line fill symbol layers.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard as claimed in any one of claims 1 to 7 are implemented.

9. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of a method for expressing nautical chart features with computer graphic symbols under the IHO S-52 standard as claimed in any one of claims 1 to 7.

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