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irrigation, or reclamation oi swamp areas 
ent accuracy to be used in the publication of maps on a 
HBp l inch = one-half mile), with a contour interval of 
>r 10 feet. 
kirveis . as in which there are problen >f average 
k importance, such as most of the basin of the Mississippi 
|jts tributaries, are made with sufficient accuracy to be used 
B publication of maps on a scale of (1 inch = nearly 
V), with a contour interval of 10 to 25 feet. 
.purveys of areas in which the problems are of minor 
i importance, such as much of the mountain or desert 
! of Arizona or New Mexico, are made with sufficient 
icy to be used in the publication of maps on a scale of 
: inch = uearlv 2 miles), with a contour interval of 25 to 
y 7 
[jet. v * 1 1 
topographic survey of Alaska lias been in progress since 
j and nearly 37 per cent of its area has now been mapped, 
t 10 per cent of the Territory has been covered by recoil- 
nee maps on a scale of or about 10 miles to an 
m Most of the remaining area surveyed in Alaska Las 
happed on a scale of but about 4,000 square miles 
ien mapped on a scale of —55. 
nit half of the Hawaiian Islands has been surveyed, and 
suiting maps are published on a scale of ^55. 
features shown on these maps may be arranged in three 
b—( 1) water, including seas, lakes, rivers, canals, swamps, 
>ther bodies of water; (2) relief, including mountains, 
[valleys, and other features of the land surface; ( 3 ) culture 
s of man), such as towns, cities, roads, railroads, and 
*1,080 
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