Which of the following statements about maps are correct? 1. Maps that maintain the true shapes of areas are known as conformal maps. 2. Maps are used to show spatial relationships. 3. Maps cannot show route from one place to another. Select the correct answer using the code given below.
- (a)2 and 3 only
- (b)1 and 3 only
- (c)1 and 2 only
- (d)1, 2 and 3
Correct — C, 1 and 2 only. Statement 1 is the textbook definition — a conformal projection preserves the true shape of small areas by keeping angles correct at every point, the Mercator being the standard example. Statement 2 is what maps are for: they show where things lie in relation to one another, which is spatial relationship. Statement 3 fails on sight, because route-finding is one of the oldest uses of a map, and any road or rail map is a counter-example.
- (a)2 and 3 only — Accepts the false claim that maps cannot show routes and throws away the correct definition of a conformal map.
- (b)1 and 3 only — Keeps the conformal definition but again admits statement 3, which any road map disproves.
- (d)1, 2 and 3 — Would be right if statement 3 were true; route maps, from a city bus network to an air-route chart, show that it is not.
A map is a flat model of a curved surface, so something always has to give. A projection can preserve shape (conformal), or area (equal-area), or distance from a point, or direction — but never all of them at once. Choosing a projection is choosing which distortion you can live with.
Statement 3 is the giveaway, and it is worth noticing why an examiner plants such an obviously false line: it lets the item test whether you will change a correct reading of statements 1 and 2 to fit a code you half-remember. Work each statement on its own and mark the code last. The conformal-versus-equal-area contrast is the one substantive idea here — Mercator keeps shapes and angles and badly inflates Greenland, while an equal-area projection such as Mollweide keeps sizes honest and distorts shapes.
- A conformal projection preserves angles, and therefore the true shape of small areas; Mercator is the classic case.
- An equal-area projection preserves relative size, at the cost of shape.
- On a Mercator map a line of constant compass bearing is straight, which is why it survives in navigation.
- Maps are classified by scale as large scale (cadastral and topographic) and small scale (atlas and wall maps).
- Distance, direction, area and shape cannot all be held true on one flat map.
- Reading 'conformal' as 'conforming to the ground truth in every respect'.
- Letting a wrong third statement push you into changing a correct reading of the first two.
Three statements plus a code, or a single-line item asking what a named projection preserves.
In order to find out the absolute location of a place on the map, which of the following will be required?
- (a) Latitude of the place alone
- (b) Longitude of the place alone
- (c) Both latitude and longitude of the place
- (d) Neither latitude nor longitude of the place
Answer(c) Both latitude and longitude of the place
The companion skill from the year before — what a map has to give you before a place can be pinned down absolutely rather than described relative to something else.
- practice — not a real PYQ
A map projection that preserves the true shape of small areas is called
- (a)equal-area
- (b)conformal
- (c)equidistant
- (d)azimuthal
Answer(b) conformal — it holds angles true at every point, so small shapes come out right.
- practice — not a real PYQ
The Mercator projection remained popular for sea navigation because on it
- (a)areas are shown in true proportion
- (b)a line of constant compass bearing is a straight line
- (c)the shortest route between two points is a straight line
- (d)distances are true in every direction
Answer(b) a line of constant compass bearing is a straight line — a rhumb line can be ruled straight onto the chart.