September 9, 1909J 



NA TURE 



327 



Forests, woods, marshes, and in some cases pasture, 

 rough pasture, orchards, vuieyards, gardens, &c., are 

 shown by conventional signs. While forests, woods, and 

 marshes should certainly be distinguished on the maps, I 

 incline to the opinion that the state of cultivation is better 

 omitted, and that the less small detail shown the better. 

 Such small detail increases the cost and often overcrowds 

 the map. The German , mhs^ scale shows much small 

 detail, and although the maps are beautifully and delicately 

 etigraved on copper, the detail is rather crowded on some 

 sheets. The French Carte Vicinale is, in my opinion, 

 rather crowded with names. 



The most difficult question, and that on which opinions 

 differ most, is the method of representing ground forms. 

 Methods which answer well on steep ground are less satis- 

 factory on gentle slopes, and vice versd, and each method 

 is open to some objection. 



Ground forms may be indicated by contours, hill shading 

 in stipple, vertical hachures, horizontal hachures, the layer 

 system, or by a combination of some of these. 



Ground forms are represented by contours on the ^t-Suvti- 

 scale maps of the German States, the Swiss Siegfried Atlas, 

 the maps of the United States, the i-inch map of Canada, 

 the ^jJ-ijTT-scale map of Denmark, and the maps of Japan. 

 Where the slopes are steep the contours give almost the 

 effect of hill-shading. Some of these maps give a very 

 good representation of the ground, the best being those in 

 which the contours are in colour. 



Hill features are shown by stipple shading on the French 

 Carte Vicinale and the Ordnance Survey four-mile map. 

 In mountainous country stipple shading gives a good 

 pictorial representation of the ground, but it fails in flatter 

 country, and it is often difficult to tell from it which way 

 slopes run. 



The Swiss Dufour .^tlas (t o Aim scale) is a good example 

 of vertical hachuring, as are some of the German 'tttwifs- 

 scale maps. Vertical hachures are also used on the 

 Austrian and Swedish maps, and in conjunction with con- 

 tours on the maps of several other countries. 



Vertical hachures when well executed give an artistic 

 and graphic representation of the hills. In the Swiss and 

 British maps the pictorial effect is enhanced by assuming 

 a light from the left-hand top corner. In steep ground, 

 especially when the hachures are in black, these are apt 

 to obscure detail and names. I think hachures are better 

 when printed in colour, but many will disagree with me 

 on this point. 



Horizontal hachuring, while having some advantages, is 

 less effective and is little used. 



The system generally known as the laver system has 

 been used in Great Britain by the well-known Scotch firm 

 of J. Bartholomew and Co., has recently been adopted 

 by the Ordiiance Survey for its J-inch maps, and is used 

 in the J-inch maps of Canada. It consists in indicating 

 by various shades of colour the area lying between certain 

 contours ; thus one shade may be given to all ground 

 below the 50-feet contour, another shade to ground between 

 the 50-feet and loo-feet contour, and so on. This system 

 gives a general indication of ground form and enables the 

 contour lines to be followed more easily. Its shades of 

 colour enable the eye to pick out more easily all land 

 lying at about the same level. It is most effective in 

 !?i-ound with a small range of vertical height, as the vertical 

 depth of layers can then be small and the distinction in 

 colour between successive layers marked. In hillv ground 

 the depth of the layer must be increased, which means 

 that tnanv ground features are ignored on the map, or the 

 number of layers on the map must be large, in which case 

 the distinction in shade between successive layers will be 

 less marked. This method is popular in Great Britain, 

 and enables those who are not versed in rending contours 

 and hachures to realise something of the nature of the 

 groLmd forms. 



.\ combination of these methods has been used as 

 follows : — 



France on her -xi^-rTr -scale maps shows ground forms by 

 contour lines and stipple shading. This gives a very fair 

 representation of the ground, but where the contours are 

 very close together the effect of the coloured contours on 

 the stipole is not nleasant. Nor docs the stipple always 

 look well when it falls on colour. 

 XO. 20S0, VOL. 81] 



The German coloured urirVtrTi -scale map, the Italian 

 nro'dTrTT' anJ the British i-inch show both contours and 

 vertical hachures. 



The Norwegian ^jTjVirfr -scale map shows the features by 

 contours, vertical hachures and shading. 



The new British ^-inch scale map has both contours, 

 layers and stipple shading. 



Opinions differ so much on this subject, and there is so 

 much to be said for and against each method, that I will 

 confine myself to the opinion that contours reasonably 

 close together should form the principal feature of any 

 method of representing ground forms ; that contours by 

 themselves give a very fair representation of the ground ; 

 that vertical hachures, if printed so as not to obscure the 

 detail and names, or stipple shading when there is not 

 too much colour on the maps, increase the pictorial effect 

 and are useful additions to contours; that ground forms 

 should preferably be in colour, and that where hachures 

 or stipple are used as well as contours both should be in 

 the same colour. 



nie German coloured Y^-jViiTi-scale map (brown hachures 

 and contours), the British i-inch scale copper-plate printed 

 map (brown hachures and black contours), the British 

 I-inch coloured map (brown hachures and red contours), 

 and the French ^ifijij-scale (grey stipple and brown con- 

 tours), all give a good representation of the ground, and 

 there are other maps which might be named almost, if not 

 quite, as good. 



]'ertical Interval of Contours. 



The vertical interval between contours should depend 

 partly on the scale, partly on the steepness of the ground. 

 Practice varies considerably in this matter. 



The ^-sJinr-scale maps of Switzerland and of Germany, 

 except Prussia, are contoured at lo-metre intervals. 



The .jj^THT-scale maps of France are contoured at lo-metre 

 intervals. 



The 3^j-scale maps of Japan and Spain are contoured 

 at 20-metre intervals. 



On the Swiss jt,^ scale contours are 30 metres apart. 



On the United States j^bir scale the contour interval 

 varies from 20 to 100 feet. 



On the British i-inch map there are contours at 5° feet, 

 at every 100 feet up to 1000 feet, and thence at 250-feet 

 intervals. 



On the Canadian i-inch and J-inch maps the contour 

 interval is only 25 feet, but the sheets published have been 

 in ground with only moderate elevations. 



On the German iirffViriT-scale the contour interval is 50 

 metres. 



I consider that if the contours are printed in colour the 

 vertical interval may with advantage be such that on steep 

 ground the contours are reasonably close together, every 

 fourth or fifth contour being printed heavier so as to be 

 more easily followed. If the contours are in black they 

 cannot with advantage be so close. 



It is, in my opinion, best if the contour interval is 

 uniform all over a country. Failing this, it seems desirable 

 that it should be uniform over considerable areas and at 

 least throughout a sheet ; but this view is not universally 

 held. I do not like the varying interval adopted by the 

 Ordnance Survey. The contours on the Ordnance Survey 

 maps are surveyed with great accuracy and at great 

 expense. For topographical maps much cheaper and more 

 rapid methods will suffice. 



Cartography. 



I have, with a view to clearness, kept the question of 

 the method of reproduction separate, but it has a bearing 

 on some of the points already considered. Thus the fine 

 engraving of the German y^jVirir -scale map enables an 

 amount of small detail and ornament to be shown on that 

 map which could not have been clearly shown if any other 

 method of reproduction had been used. 



The older maps were generally engraved on copper, or 

 sometimes on stone, and printed in black and white. Sub- 

 sequently photographic methods, such as the photogravure 

 of the Austrian and the more recent ytrjin-scale French 

 maps, were used, and colour printing is now largely re- 

 sorted to. 



