What you’ll learn
Interpret positive and negative numbers.
Key idea
A positive elevation is above the reference; a negative elevation is below it.
Magnitude provides separation, not above/below direction; the sign must be read relative to the stated zero reference.
Worked example
Classify examples and non-examples for the concept 'Interpret positive and negative numbers'.
A station has elevation -45 m relative to sea level 0 m. Is this an example of a position below sea level? Classify with sign evidence.
- Sea level is the stated zero reference.
- The negative sign gives the below direction, with distance 45 m.
Answer: Example — -45 m places the station 45 m below the zero reference.
Quick Check
Classify examples and non-examples for the concept 'Interpret positive and negative numbers'.
A station has elevation -20 m relative to sea level 0 m. Is this an example of a position below sea level? Classify with sign evidence.