On map making, see [page 111].
A map is useful, and, on an extended tour, almost necessary. Topographic maps, showing towns and roads also, of a large part of the United States are published by the United States Geological Survey. Better maps could not be desired. Different regions are mapped to different scale, but, for the greater part, each map or “quadrangle” covers an area measuring 15′ in extent each way; the scale is 1:62,500, or about a mile to an inch. Each quadrangle measures approximately 12¾ × 17½ inches and displays an area of 210-225 square miles, the area varying with the latitude. To traverse one quadrangle from south to north means, if the country be hilly and the roads winding, to walk twenty miles or more.
On these maps water is printed in blue, contour lines in brown, and cultural features—roads, towns, county lines—in black. A contour line is a line which follows the surface at a fixed altitude; one who follows a contour line will go neither uphill nor down, but on the level. The contour interval, that is, the difference in elevation between adjacent contour lines, is stated at the bottom of each quadrangle. It is not uniform for all the areas mapped, and is greater in mountains and less in level regions. Every fourth or fifth contour line is made heavier than the others.
A little experience will teach one to read a contour map at a glance; the shape of the hills is indicated, and their steepness. In addition, these maps bear in figures (and in feet) actual elevations above sea level.
Besides the quadrangles on the unit of area mentioned, the Survey publishes maps to larger scale, of regions of exceptional importance: Boston and vicinity, for instance; Washington and vicinity; the Gettysburg battlefield; the Niagara gorge; Glacier National Park; industrial regions such as Franklin Furnace, N. J., and vicinity.
Application may be made to The Director, United States Geological Survey, Washington, D. C., for an index map of any particular region in which one is interested; the index map is marked off into quadrangles, and each quadrangle bears its distinctive name. Information regarding larger maps is also given. So that, on consulting the index map, one may order by name the particular quadrangles or larger maps he may desire. The price of the quadrangles is ten cents each, or six cents each for fifty or more. The larger maps units are of varying price.
For remoter regions, not yet mapped by Government, ruder maps may ordinarily be had.
Such foreign regions as the Alps are, of course, perfectly mapped. The maps in Baedeker’s guidebooks are good, and better still may be had, if one desires.
It is a good plan to have the maps of one’s home region mounted on linen and shellaced.
Map case. Maps of small size and constantly in use may be put in form for carrying by cutting them into sections and mounting them on linen, with spaces for folding left between the edges of adjacent sections. A map so mounted may be folded and carried in an oiled silk envelope. Leather is not a satisfactory material for such a case, for, when carried in one’s clothing, it becomes wet through with perspiration.