7.3.2 
Observing the environment 
Functionality level 1 
Functionality level 2 
Function 
Input information 
Output information 
1. Observe hydrographic 
data 
1.1 Observe water depth 
1.1.1 Record data 
• Measured water depth under 
keel 
• Present draught of ship 
• Recorded information for determining the water 
depth 
1.1.2 Evaluate data 
• Output information from 1.1.1 
• Water depth 
1.1.3 Provide information 
• Output information from 1.1.2 
• Output of water depth, or water depth under the 
keel, for the user 
• Provision of water depth, or water depth under 
the keel, for use by other functionalities 
1.2 Observe current 
1.2.1 Record data 
• Course and speed through 
water and over ground (supplies 
total drift, see below) 
• True wind (direction and speed) 
• Current charts/tide tables 
• Recorded data for determining the current 
speed and direction 
1.2.2 Evaluate data 
• Output information from 1.2.1 
• Current speed and direction (generally esti 
mated value) 
1.2.3 Provide information 
• Output information from 1.2.2 
• Output of current for the user 
• Provision for other functionalities 
2. Observe meteorological 
data 
2.1 Observe wind 
2.1.1 Record data 
• Measured wind speed and di 
rection 
• Speed over ground 
• Heading 
• Recorded information for determining the rela 
tive and true wind speed 
2.1.2 Evaluate data 
• Output information from 2.1.1 
• Calculated values for true wind speed and 
direction 
2.1.3 Provide information 
• Output information from 2.1.2 
• Output of wind speed and directions for the 
user 
• Provision of wind speeds and directions for 
other functionalities of the INS