雅思阅读第079套P3-Map wars

Reading Passage 3

You should spend about 20minutes on Questions 28-40 which are based on this passage.

Map wars

A map of the world expresses apoint of view. A correct model of the earth is a sphere - or an ellipsoid to beprecise. Photographs of the earth from space provide comforting reassurance onthat point. If you wish to know the relative positions of the continents andthe oceans you should go out and buy yourself a globe and spin it around.

But a globe cannot be pinned toa wall or printed in a book. For that you need a two-dimensionalrepresentation. This is where the problems start since you cannot projectthree-dimensional information onto a flat plane without making certainassumptions. The arguments between cartographers mostly concern what thoseassumptions should be.

The simplest two-dimensionalrepresentation is a 'cylindrical’ projection - what you get by wrapping a sheetof paper around a globe and simply transferring the information across. Thismeans it indicates true north and south. So, Newfoundland is directly north ofVenezuela and it appears that way on the map. East and west similarly are alsoindicated correctly. Such a map demonstrates what is called 'fidelity of axis’.

One of the longest-livedcylindrical projections was based on the needs of sixteenth century navigators.Gerhard Kremer, a Flemish mathematician, produced his view of the world in1569. 'Kremer’ translates to 'merchant’ in English and 'mercator’ in Latin. Andthe Mercator projection survives to this day in many books and maps.

Mercator’s projection of theworld also shows intermediate compass directions like north-west more or lessaccurately. So, it is possible to conclude from his map that Brazil issouth-west of Liberia and if you plot a course in that direction you willeventually arrive at your destination. No wonder it was appreciated by theearly explorers! If it can be used in this way a map is said to have 'fidelityof angle’.

But fidelity of angle is onlyachieved at a cost. To make it work, the further away you get from the equator,the further apart you have to move the horizontal lines of latitude. As thesedistances increase so do the sizes of the countries underneath them. So, by thetime you get to the North or South Poles the lines would be drawn infinitelyfar apart and the Arctic and Antarctic regions can scarcely be represented atall since they would be infinitely large. More importantly the relative sizesof intermediate areas are completely distorted; South America seems smallerthan Europe whereas in fact it is twice the size. These changes in scaledistort both the size and shape of countries. Given such defects, it issurprising that the Mercator projection has survived so long, especially asdozens of other more satisfactory projections have appeared since. One of thebest known of these is the Aitoff projection of 1889, which attempted torepresent country sizes and shapes more correctly. But to do so required acompromise - the lines of latitude and longitude had to be 'bent’. Fidelity ofaxis had thus been lost and you could no longer judge north, south, east andwest so easily. Most of us, however, did not notice that these projections weredifferent from Mercator. We assumed that all maps were simply factual statements.

Dr. Arno Peters, a Germanhistorian, was irritated by the maps he saw widely published, particularly bythe survival of Mercator which he argued, gave a euro-centric view of theworld. It shrank the developing countries since most of these are around the equator,and it expanded the richer countries since they lay further north. Even theequator itself is shown two thirds of the way down on the traditional Mercatormap. Dr. Peters insisted that his map, which first appeared in 1985, hasequal-area projection so that no country is given prominence over another, plusfidelity of axis to avoid the disorientating effect of bent lines of latitudeand longitude.

Then there is the question ofcountry shape. If you were to take a photo of a globe in its normal positionyou would find the countries around the equator like Zaire or Ecuador came outof it pretty well. They would be shown relatively large and with somethingclose to their correct shape. But further north or south there are considerabledistortions: Australia tails away alarmingly. Dr. Peters decided that theminimum distortions should occur not at the equator but at the 45 degree linesof latitude, as these are much more populated areas. However, thiscontroversial Peters map does radically change the shape of both Africa andSouth America; and although all projections distort to some extent, it is clearthat Africa appears exceptionally long and thin on the Peters map.

But the oddity of the Petersprojection is at least partly responsible for its success, as there has beenwidespread discussion on the misrepresentation of country sizes in previousmaps. The issues which the Peters map raises are relatively simple. If youdecide you want an equal area map with fidelity of axis you will always getsomething resembling the Peters projection. If you decide that shape is moresignificant you will get something else.

The real value of the Petersprojection is that it has made the world think about something that before wasnever taken seriously: that maps of the world represent a point of view just asdo press articles or TV programmes or photographs. But it isn’t recommendedthat you navigate a '747’ round the world with the Peters projection or withany other single global projection they would all lead you astray!

SECTION 3: QUESTIONS 28-40

Questions 28-31

Complete the summary.

Choose your answers from thebox below the summary.

List of Words

axis

estimate

perspective

map

direction

compare

size

judge

accurately

angle

distances

models

projection

change

There are more wordsthan you will need to fill the gaps.

For four centuries, map makers have been trying to convert three-dimensional information as accurately (example) as possible onto a two-dimensional plane. However, each method of 28 _________________ involves a compromise. Thus Mercator’s projection indicates true north and south, known as fidelity of 29_________________ , but misrepresents the relative size of countries.

To avoid this distortion, other cartographers rounded the lines of latitude and longitude. Dr. Peters felt that such maps presented a first-world 30 _________________. His map, with equal area projection, enables us to 31 _________________ the size of one country with another.

Questions 32-36

Use the information in the textto match the map projections [M A P] with the characteristics listed below.

M

Mercator projection

A

Aitoff projection

P

Peters projection

Example

designed for the needs of earlynavigators M

32 __________makes Europe seem larger than it is

33 __________maximum distortions at the poles

34 __________maintains greatest accuracy at 45 degrees latitude

35 __________most distorts the position of the equator

36 __________more accurately represents country shapes and sizes

Questions 37-39

Choose one drawing (A-D)to match each of the three projection types (37-39).

There are more drawings thannames so you will not use all of them.

37 __________Mercator projection

38 __________Aitoff projection

39 __________Peters projection

Question 40

Choose the correct letter A-D.

40The main point made by the writer of thisarticle is that we need to ...

Aunderstand maps.

Bunderstand map-making.

Cunderstand that maps are not objective.

Dunderstand the importance of latitude andlongitude.