S57 Chart Symbols Library Management: Symbol Library Format Parsing and Expansion

# 1. Introduction

In this chapter, we will delve into the topic of S57 map symbol library management. We will first introduce the background, understanding the role and importance of the S57 map symbol library, as well as the purpose and significance of this article. Let's start to explore this challenging topic.

# 2. Overview of S57 Map Symbol Library

The S57 map symbol library is a commonly used symbol library in chart production, used to display various geographical features and characteristics in nautical charts. Below we will elaborate on the concept, structure, and advantages of the S57 map symbol library.

### What is the S57 Map Symbol Library

The S57 map symbol library is a symbol library format defined by the International Hydrographic Organization, used to standardize the symbol representation of various geographical elements in nautical charts. These symbols include various information such as navigation marks and depths in the sea area and near the coastline.

### Structure and Features of the S57 Symbol Library

The S57 symbol library adopts an object-based data model, representing various geographical elements as objects and encoding them for storage. The symbol library contains symbols, attributes, and associated relationships for various map elements, making chart production more standardized and规范化.

Features of the symbol library include: standardized coding specifications, support for the representation of various map elements (such as navigation marks, depth contours, etc.), and ease of expansion and customization.

### Advantages of Using the S57 Symbol Library

Using the S57 symbol library can make nautical chart production more efficient and accurate. By using a unified symbol library, consistency between different chart production units can be ensured, improving the efficiency and quality of chart production. In addition, the standardization of the symbol library facilitates the updating and maintenance of charts.

In summary, the S57 symbol library plays a crucial role in nautical chart production, providing important technical support for map production in the maritime field.

# 3. Symbol Library Format Analysis

In this chapter, we will delve into the format analysis of the S57 symbol library, including the common elements and attributes, the parsing and understanding of data formats, and the relationships and roles between the elements of the symbol library. Let's learn more about the internal structure and implementation details of the S57 symbol library.

#### Common Elements and Attributes of the S57 Symbol Library

In the S57 symbol library, the following common elements and attributes are usually involved:

1. **Symbol Entity**: The basic display element in the symbol library, used to represent specific objects or elements in the map.
2. **Layer**: In the symbol library, symbols are usually organized and managed by layers, and different layers may contain different types of symbols.
3. **Attributes**: Each symbol may have a series of attributes, used to define the appearance, size, color, and other information of the symbol.
4. **Relationships**: There may be various relationships between the elements in the symbol library, such as the association between symbols and attributes, and the organizational relationship between symbols and layers.

Understanding these common elements and attributes is very important for in-depth analysis and operation of the S57 symbol l