Cartography

“ The value, for this purpose, of so patent a phenomenon as the rising and setting of the sun must have been impressed upon human intelligence at an elementary stage. Again, map-making is not very far removed from a primitive instinct. Modern travellers have described attempts at cartography by the North American Indians, the Eskimo, and the Maori and other less advanced inhabitants of the Pacific Islands. ”

“ As a rule, cartography begins with road-maps. Peoples whose territory is a terminating point or is traversed by important trade-routes, and who perform a carrier-service, are accustomed as a matter of course to learn to depend upon drafted representations of their roads. Appolonius Rhodius says that such maps were used by the ancient Colchians of the Southwestern Caucasus and Northern Armenia, through whose territory ran the great caravan routes from the Black Sea to the East and South. ”

“ The study of geography was advanced by improvements in cartography (see Map) , not only in the methods of survey and projection, but in the representation of the third dimension by means of contour lines introduced by Philippe Buache in 1737, and the more remarkable because less obvious invention of isotherms introduced by Humboldt in 1817. ”

“ The larger work occupied thirty-two years, and was accomplished with complete success. The map in 25 sheets on the scale of 1/100000 was published at intervals between 1842 and 1865, and is an admirable specimen of cartography. ”

“ It is not too much to say that the honour of being their lucky discoverer has long been considered as the highest possible prize to be obtained amongst students in the field of ancient cartography. But until the summer of 1901, although many copies of the book are known in various editions, no specimen of either the globe or map has ever been seen or heard of in modern times. ”

“ Cartography is a powerful aid to scientific geography, inasmuch as it arranges in true projection a great mass of heterogeneous materials, bringing it before the eye within small space, and thus making apparent relations which else could hardly be noticed. As for political geography, viz., the description of the various empires of the world, their area, provinces, population, etc., this we would regard rather as a branch of statistics than of geography proper.—Gaea. ”

“ Introduction Hydrography is the science of measurement and description of the features which affect marine navigation, including water depths, shorelines, tides, currents, bottom types, and undersea obstructions. Cartography transforms the scientific data collected by hydrographers into data usable by the mariner, and is the final step in a long process which leads from raw data to a usable chart. ”

“ The reduction and selection of details from a large-scale survey for use on a small general map, the methods of representing such details, the permissible limit of generalizing them, the choice of colours—these and other aspects of cartography really demand a scientific standard as exalted in its way as that of the surveyor. ”

“ It is no part of a history of geography to deal with that of meteorology or of geology, though141 both these sciences are fundamentally geographical, owe an obvious debt to exploration and travel, and make ample use of cartography. On the other hand, there are some departments of research which, though standing under their own names, are grouped perhaps more closely as offspring of physical geography. ”

“ Fig. 8.—Edrisi's Map, a. d. 1154.
extent. It is rather for the preservation of what was previously known that we are indebted to the Arabs; for, though they studied geography with great assiduity, they can not be said to have greatly advanced it as a science.
Leaving the Arabs and their labors for the present, we will now return to the growth of cartography in Europe. We have maps designed to represent the earth as known, or particular parts of it, from the ninth to the fifteenth century ”

“ An excellent example of mediæval cartography, before these results and others like them began to show their influence on maps, is provided by the celebrated map preserved in Hereford4748 Cathedral, made about 1280 by Richard of Haldingham. Here is the world still shown as a round disk, with little conception of the form of the Mediterranean and its branch seas; while even the British Isles and north-west Europe are strangely distorted to fit the circle. Such is an illustration of the conception of the world still existing in western Europe. ”

“ The atlas which accompanies this valuable study is made np of a large number of admirable facsimiles and copies of early maps, some of which are reproduced in the present memoir. It is certainly the best single book for the student of early American cartography. ”

“ They are ascertained by a combination of actual measurement of the highest precision on the surface and{ angular observations of theMathematical geography. positions of the heavenly bodies. The science of geodesy is part of mathematical geography, of which the arts of surveying and cartography are applications. The motions of the earth as a planet must be taken into account, as they render possible the determination of position and direction by observations of the heavenly bodies. ”

“ The lines should preferably run across the long axis of an area, not parallel to it, and the predominating trend or general direction of the areas of one geologic formation on a map should decide the direction of the lines for all areas of that formation on the same map, even if the rule must be violated on some of the minor areas.
An effort should always be made to produce a pattern that is subordinate in strength to the main lines of the base map on which it is drawn. In black and white maps, as in colored maps, unlike patterns should be placed next to each other. ”

“ Much the same may be said of the dikes of cooled magma which have been injected along preëxisting fractures.
The base of the geological map.—Modern topographic maps form an important part of the library of the serious student of physiography; they are the gazetteer of this branch of science. Every civilized nation has to-day either completed a topographic atlas of its territory, or it is vigorously prosecuting a survey to furnish maps which represent the relief with some detail, and publishing the results in the form of an atlas of quadrangles. ”

“ The scale of that map, as determined by the equator or centre meridian, we will suppose to be 1:125,000,000, while the encircling meridian indicates a scale of 1:80,000,000; and a “mean” scale, equal to the square root of the proportion which the area of the map bears to the actual area of a hemisphere, is 1:112,000,000. In adopting a scale for their maps, cartographers will do well to choose a multiple of 1000 if possible, for such a scale can claim to be international, while in planning an atlas they ought to avoid a needless multiplicity of scales. ”

“ The great value of the modern topographical map is becoming, however, universally acknowledged, and every highly civilized nation has either completed or has in preparation sectional topographical maps of its domain on such a scale as is warranted by its financial condition and its state of development. Thus there is now being accumulated a vast library of geographical and to some extent geological information, of which the student of geology must be prepared to make use. ”

“ Map Projections are dealt with separately below. It will suffice therefore to point out that the ordinary needs of the cartographer can be met by conical projections, and, in the case of maps covering a wide area, by Lambert’s equal area projection. The indiscriminate use of Mercator’s projection, for maps of the world, is to be deprecated owing to the inordinate exaggeration of areas in high latitudes. In the case of topographical maps sheets bounded by meridians and parallels are to be commended. ”

“ The degree of generalization in the geologic and other detail to be shown on a map usually involves a corresponding degree of generalization in its base. Absolutely true generalization means the same degree of omission of detail for each kind of feature. If a base map on a scale of 1 mile to 1 inch, prepared with the usual detail, were placed before a camera and reduced to a scale of 16 miles to 1 inch, the lines representing the smaller tributaries of streams and the smaller water bodies, as well as many other features, would probably be so greatly reduced in length as to be illegible. ”

“ What the ideal geographer, as cartographer, first of all tries to do is to devise a notation by which he and his fellow-geographers, by the inspection of a map of a given region, may get a simultaneous vision of the terrestrial phenomena which all the explorers and observers of that region have collectively seen. Now it must always be that however minutely observed and explored a region—even the most inhabited—may be, there is always something new to be observed, even in the shape and configuration of the surface, for these are always changing ”

“ Measurement of Distance.—The shortest distance between two places on the surface of a globe is represented by the arc of a great circle. If the two places are upon the same meridian or upon the equator the exact distance separating them is to be found by reference to a table giving the lengths of arcs of a meridian and of the equator. In all other cases recourse must be had to a map, a globe or mathematical formula. Measurements made on a topographical map yield the most satisfactory results. Even a general map may be trusted, as long as we keep within ten degrees of its centre. ”

“ If the geology be other than of the very simplest character—and this will generally be true of mountainous regions—it is not only necessary to fix the geographical positions of rock masses, but their elevations as well. In other words, the map must not only be a plan, but special elevations must be represented, known as geological sections. The most satisfactory representation—and this will be essential for all difficult areas—will be one which shows not only special elevations, but the topographic relief of every point in the area. ”

“ The conventional patterns used on a map to distinguish separate areas, chiefly geologic, are shown in Plate VIII. The patterns shown represent the proper combinations of lines, dots, and other forms and should be spaced openly or closely according to the size of the area covered, the contrast needed between areas, and the general clearness and effect desired. If a map is to show both small and large areas dense or closely spaced patterns should generally be used for the smaller areas, even if they may be required for some fairly large areas representing the same formation or condition. ”

“ These publications are illustrated with well-selected half-tones and carefully prepared black and white maps based on the accurate topographic maps issued by the Geological Survey.
The first need of the intelligent traveler is a map of the area he is about to traverse. Fortunately excellent maps of almost all the larger parks are for sale by the United States Geological Survey at nominal prices. Maps have been published of Yellowstone, Yosemite and Glacier national parks on a scale of 2 miles to the inch ”

“ In preparing an original geologic map a letter symbol, such as has been just described, or a number should be put in the proper place in the explanation, and the same symbol or number should be repeated at one or more places on the map within the areas to which it refers. Each area that is indicated by a color should be marked with the proper symbol in order to make its identification sure, for light colors especially are likely to fade and mixed colors can not be discriminated with certainty. ”

“ Where such rigid geodetic operations were instituted previous to the hydrographic survey of the coasts and waters, they furnish the hydrographic surveyor, not only with the correct outlines of the coast, but also with the precise position of the landmarks upon which he may base his work, or, in other words, a skeleton for the same. But, when such surveys are not existing, he is compelled to lay down the coast-line also, with its detail as far inland as there are landmarks auxiliary to navigation, thus performing the labors of the topographer as well as those of the hydrographer. ”

“ Many a cartographer, burning with desire to draw a good map of a newly explored region, has been driven to despair by the inadequacy of the route surveys in his hands. Not a few of these surveys have been unworthy of reproduction in the books of the explorers who made them, and the best that could be done was to generalize their information on maps of comparatively small scale. ”

“ Study a good map—a quadrangle of the U. S. Geological Survey, for instance. Note what things are represented, and how representation is made: study the map, until it is thoroughly understood.
There are three factors with which the map-maker deals: direction, distance, and elevation. With the first, he must always reckon, and usually with the second and the third as well.
Direction is fundamental. Suppose there are three dominant points in the area to be mapped, relatively situated as here indicated. ”

“ The progress of geography, as manifested on our maps, is much slower than might be supposed from the number of useful results which are found scattered in the works of different nations. Astronomical observations and topographic information accumulate during a long lapse of years, without being made use of; and from a principle of stability and preservation, in other respects praiseworthy, those who construct maps often choose rather to add nothing, than to sacrifice a lake, a chain of mountains, or an interbranching of rivers, which have figured there during ages. ”