WEEK 4 LEC NAV 6 VIDEO

Summary

This lecture delves into the operational use of Electronic Chart Display and Information Systems (ECDIS) for safe navigation, contrasting ECS and ECDIS, and the importance of using official charts. It explains the types of electronic charts, vector and raster, and their applications. The lecture also covers the presentation of ENC data, the integration of systems like AIS and radar, and the significance of data accuracy and confidence zones in navigational safety.

Takeaways

• 📚 The lecture focuses on the operational use of Electronic Chart Display and Information Systems (ECDIS), emphasizing the importance of understanding the differences between various electronic chart systems and their data formats for safe navigation.
• 🌐 ECDIS must comply with the International Maritime Organization (IMO) and the Safety of Life at Sea (SOLAS) convention, ensuring the use of the latest Electronic Navigational Charts (ENC) and proper route planning and monitoring functions.
• 🗺️ There are two main classes of navigational electronic chart systems: the ECDIS which meets IMO's chart currency requirements and the ECS, which assists navigation but doesn't meet SOLAS chart carriage requirements.
• 🔍 The difference between ECS and ECDIS lies in the fact that ECS is electronic chart software with non-approved hardware, while ECDIS is type-approved hardware with official charts, allowing it to be used for primary navigation.
• 📈 Vector charts are detailed, computerized representations of navigational data, allowing for object-based customization and alarms, whereas raster charts are scanned images of paper charts, offering a more traditional graphic orientation but less interactivity.
• 📊 The advantages of vector charts include automatic alarm generation and customizable settings, while raster charts are cheaper to produce but offer limited zoom options and require large memory capacity for corrections.
• 📈 ENC data is distributed by national hydrographic offices and can be updated through various means, including direct downloads, Regional Electronic Navigational Chart Coordination Centers (RENC), and bundled services.
• 🛠️ ECDIS interfaces with other ship equipment such as AIS (Automatic Identification System), ARPA (Automatic Radar Plotting Aid), and radar overlays to enhance navigational safety and efficiency.
• 🔑 The presentation of ENC data in ECDIS aims to provide flexibility while remaining user-friendly, allowing navigators to customize the display according to their needs, including the selection of various chart and sensor information.
• 🛑 Understanding the accuracy and confidence levels of chart data is crucial for safe navigation, with categories ranging from A1 (most accurate) to U (undefined or not set), affecting both position and depth accuracy.
• 📝 The importance of knowing the position and depth accuracy for navigational safety, as exemplified by the calculation of probable depth accuracy based on the category of the zone of confidence, is highlighted.

Q & A

What is the main learning outcome of the lecture on Electronic Chart Display and Information System (ECDIS)?

The main learning outcome is to describe the difference between Electronic Chart System (ECS) and ECDIS, including its various data formats and software, and to discuss the presentation of this data in the safety of navigation.

What does SOLAS stand for and why is it important for ECDIS?

SOLAS stands for Safety of Life at Sea. It is important for ECDIS because the system must comply with the requirements of the SOLAS convention to ensure safe navigation.

What are the two main classes of navigational electronic chart systems discussed in the script?

The two main classes are the Electronic Chart Display and Information System (ECDIS) which meets the IMO's chart currency requirement, and the ECS which can assist navigation but does not meet the SOLAS chart carriage requirement.

What is the difference between ECDIS and ECS in terms of their use for navigation?

ECDIS is a type-approved hardware and software system that can be used for primary navigation, replacing paper charts. ECS, on the other hand, is an electronic chart software that is an official chart and non-approved hardware, and it cannot be used as an aid to navigation.

What does ENC stand for and what is its role in ECDIS?

ENC stands for Electronic Navigational Chart. It is a critical component of ECDIS, as the system must be loaded with the latest ENC data for safe navigation.

What are the two principal types of electronic charts mentioned in the script?

The two principal types of electronic charts are Vector Chart and Raster Chart. Vector charts are detailed representations with object-based data, while Raster charts are similar to scanned copies of paper charts.

What are the advantages and disadvantages of using a Raster Chart in ECDIS?

Advantages include its inexpensive production and similarity to paper charts. Disadvantages include being a 'dead chart' with no alarms, limited zoom options, large memory capacity requirements, high correction costs, and readability primarily in north-up orientation.

How is an ENC chart distributed and updated?

ENC charts are distributed and updated through national hydrographic offices, regional electronic navigation chart coordinating centers (RENC), and various bundled services like Transas, EADS, and UKHO's ABCS.

What is a SENC and how does it differ from an ENC?

A SENC is a System Electronic Navigational Chart, which is an ENC chart loaded into the ECDIS system. The difference is that once loaded, it becomes part of the system's navigational data.

Can you explain the concept of 'Category of Confidence' in the context of ECDIS data presentation?

The 'Category of Confidence' refers to the level of accuracy assigned to geographical areas within ECDIS data, indicating whether the data meets a minimum set of criteria for position, depth accuracy, and seafloor features. It is represented by stars in a triangle, with 6 stars indicating the highest accuracy.

How does the accuracy of depth measurements work in ECDIS, especially with the 'A1' category?

In the 'A1' category, the position accuracy is 5 meters, and the depth accuracy is 0.5 meters plus 1 percent of the depth. For example, at a depth of 10 meters, the depth accuracy would be 0.5 meters plus 0.1 meters (1 percent of 10 meters), totaling 0.6 meters.