102 SECTIONAL ADDRESSES. 



map has never been published. And I shall give you other instances 

 where the map once published has not been adequately kept up to date. 



In deahng with the functions of a National Survey I have hitherto 

 spoken of the production of ' the map.' But there is an infinite variety 

 of maps ; and before I go further it will be as well to be clear as to 

 exactly what kinds of maps I have in mind. 



Here we are again faced with the fact that every country must decide 

 for itself what maps it requires. Because Great Britain publishes maps 

 on seven different scales it does not follow that South Africa need do the 

 same. The maps required by a country depend on local conditions and 

 circumstances. It is clearly impossible to lay down any hard and fast 

 rules, but we may perhaps arrive at some general principles. I have 

 spoken of there being an infinite variety of maps, but they may be divided 

 into different kinds and classes, and for our purpose it will be convenient 

 to consider maps under two main headings, namely, cadastral and 

 topographical. 



The name ' cadastral ' is derived from the French word ' cadastre,' 

 the meaning of which the dictionary gives as a ' register of property.' 

 But the French themselves in the ' Recueil des lois et instructions sur les 

 contributions directes ' give the meaning of the word as ' a plan from 

 which the area of land may be computed and from which its revenue 

 may be valued ' ; and it is in this rather broader sense that it is usual 

 to define cadastral maps. The essence of a cadastral map is that one 

 should be able to calculate areas accurately from it, and to define and 

 show property boundaries ; and this implies that such maps must show 

 a good deal of detail, and be drawn on a large scale. While cadastral 

 maps should, and usually do, show all the detail necessary for the purposes 

 mentioned above, it is not uncommon to find that they omit certain other 

 details which, though conspicuous on the ground, are not essential for the 

 definition of property, etc. 



The purpose of a topographical map, on the other hand, is to show 

 the physical features of the country. These may of course be shown on 

 any scale, and there is no reason why a cadastral map on the largest 

 scale should not at the same time be a complete topographical map. But 

 for various reasons — among others, economy and convenience — topo- 

 graphical maps are usually on smaller scales, and consequently omit 

 certain details which cannot conveniently be shown on such scales, and 

 which are not essential to showing the topography of a country. A topo- 

 graphical map must show all the general details and physical features 

 of the country — rivers, roads, railways, buildings, forests, etc.^ — and it 

 must also show the ground forms and general levels adequately. It need 

 not necessarily show hedges and fences, and these and similar small details 

 are often omitted owing to limitations of scale. A cadastral map, on the 

 other hand, must show the small details such as hedges and fences, since 

 these so often constitute property boundaries ; but it need not show 

 ground forms. 



My own view is that it is the proper function of a National Survey to 

 make adequate provision for maps of these two kinds, cadastral and 

 topographical, because I consider them of such great importance to any 

 Community and any country for the following reasons. 



I 



