Geographical sign conventions — identify the incorrect longitude sign Which of the following statements about the signs of latitude and longitude is incorrect?
-
ALatitudes north of the equator are taken as positive
-
BLatitudes south of the equator are taken as negative
-
CLongitudes east of Greenwich are taken as negative
-
DLongitudes west of Greenwich are taken as positive
-
EBoth (c) and (d) of the above
Answer
Correct Answer: Both (c) and (d) of the above
Explanation
Introduction / Context:Mapping and GPS computations adopt a consistent sign convention for latitude and longitude. Misunderstanding the sign can flip hemispheres and lead to large positional errors.
Given Data / Assumptions:
- Standard geodetic convention is used.
- Positive and negative refer to numerical signs.
Concept / Approach:
The usual convention assigns: latitude north positive, latitude south negative; longitude east positive, longitude west negative. Therefore, statements claiming east is negative or west is positive are incorrect.
Step-by-Step Solution:
Check (a) → true.Check (b) → true.Check (c) → false (east is positive).Check (d) → false (west is negative).Thus (e) properly identifies incorrect statements.Verification / Alternative check:
Most GIS and GPS data formats (e.g., WGS84) follow this convention; some local systems may adopt alternatives but are rare.
Why Other Options Are Wrong:
- (a) and (b) are correct statements and not “incorrect”.
Common Pitfalls:
- Confusing the sign convention with Easting/Northing coordinates in projected systems.
Final Answer:
Both (c) and (d) of the above.