Which one of the following statements is correct in case of map versus aerial photograph?
- AMap is an orthogonal projection, whereas an aerial photograph is a central projection.Correct
- BBoth a map and a photograph have constant scale.
- CThe amount of details both on a map and on an aerial photograph is selective.
- DDue to symbolic representation, the clarity of details is more on a photo than on a map.
Solution
Concept
Orthogonal and perspective projections
Step-by-step solution
1. A map is an orthogonal (parallel-ray) projection with uniform scale. 2. An aerial photograph is a central (perspective) projection, so its scale varies with relief and tilt. 3. Maps are selective and symbolic; photographs show everything.
Explanation
The geometry of a photograph is perspective, with displacement due to relief, while a map is drawn on an orthogonal projection.
Why the other options are wrong
(b) is false because the photo scale varies; (c) is false because a photo is not selective; (d) is false since symbols make a map clearer than a photo in some respects.
Shortcut
Map = orthogonal; photo = central/perspective.
Common mistake
Assuming constant scale for photographs.
Correct answer: A) Map is an orthogonal projection, whereas an aerial photograph is a central projection.