184 THE FORMATION 
Hence it is obvious that cartographic methods should be clear and simpie, 
and that they should be uniform, so that charts and maps of widely separated 
formations may be directly compared without difficulty. It is not to be ex- 
pected that uniform methods will come into general use immediately, but 
a proper appreciation of the obligation that rests upon every ecologist to 
make his results both easily comprehensible and usable will serve to produce 
this very necessary result. In the treatment that follows, as elsewhere, no 
attempt is made to describe the general cartographic methods used by other 
ecologists, notably Fiahault. The methods employed by the author form a 
complete system, which has proved valuable, and for various reasons it 
alone is discussed here. 
231. Standard scale. The question of the scale to which charts and 
maps are to be made is of primary importance. The general principle is 
that the ratio betwcen area and drawing should be as small as possible. 
Moreover, charts and maps of the same character should always be drawn 
to the same scale, unless a good reason to the contrary exists. The ideal 
scale is 1:1, which is manifestly an impossibility. This is approached most 
nearly in the quadrat chart where the scale is 10:1. Charts of definite 
areas are made on a scale as large as possible, while maps of formations, 
regions, etc., are necessarily drawn upon a very smiall scale. General maps 
designed to show the distribution of species and formations, or the vegeta- 
tion of continents, are usually not drawn with reference to a scale at all. 
While it is manifestly impossible to use the same scale for charts and maps, 
it is feasible and desirable that they be constructed upon scales readily con- 
vertible into each other. This is most satisfactorily accomplished by means 
of the decimal system, and the various type scales are 10:1, 100:1, 1000:1, 
‘etc. The first two or three scales are used for charts of quadrats, transects, 
and circles ; the remaining ones are employed in making maps of large areas. 
No attempt has been made to draw an absolute line between charts and 
maps, but an endeavor is made to restrict the term chart to the record of 
the number and position of plants, while maps deal with the arrangement 
and location of formational areas. It is hardly necessary to point out the 
reasons why all charts and maps should be based upon the decimal system of 
scales. Experience will furnish the very best of arguments. 
232. Color scheme. The first requisite for the graphic representation 
of formations, regions, etc., is that each class of formations be invariably 
indicated by the same color. It is also necessary that the colors and shades 
be easily distinguishable, and it is at least desirable that they be referred to 
the different classes in some consistent sequence. Uniformity in all these 
