🔍 Key Concepts

• Line of position (LOP) in navigation is any line on which the navigator knows the vessel must lie • Different navigation systems (visual bearings, radar ranges, radio navigation like Loran/GPS-derived hyperbolic systems) can create different shapes of LOPs • On a chart, an LOP is simply the plotted form of "where I must be" based on a single observation or measurement

💭 Think About

• Think about what shape you get on the chart when you take a bearing with a compass on a lighthouse or other fixed object • Consider what shape results from a range from a radar or distance from a known point (like a circle or part of a circle) • Recall which older radio navigation systems (before GPS plotting as a point) gave lines of equal time difference—what geometric shape did those lines make?

✅ Before You Answer

• Be clear on the definition: a line of position is any line (or curve) that represents all possible positions that fit a single observation • Verify which of the answer choices represent possible geometric forms of such a line on a chart • Check whether the question is asking for one specific form or if it allows for multiple different shapes depending on the method used