SVJ’ 
and valleys, as well as 
that are far apart on 
that are close together 
mi together indicate a 
express altitude, form, 
SsT' 
£52 
J 
po: 
J41& 
Cl 11 i 
with a contour interval of 1 to 10< 
of the particular area mapped. j 
2. Surveys of areas in which thj 
public importance, such as most of 
and its tributaries, are made with s 
the publication of maps on a sca^ 
mile), with a contour interval of 10 
3. Surveys of areas in which 
public importance, such as much 
region of Arizona or New Mexico, 
o # 
of the northwest, are made with su 
the publication of maps on a scab 
miles) or 2l ~ (1 inch = nearly 4 m 
of 20 to 250 feet. 
The aerial camera is now being r 
information recorded on the phol 
which show only drainage and culti 
areas in the United States. By th 
apparatus, aerial photographs are u 
the regular topographic maps, wl 
drainage and culture. 
A topographic survey of Alaska 
1898, and nearly 44 percent of its 
About 15 percent of the Territory] 
qii a scale of (1 inch = nearly 
remainder of the area surveyed tl 
scale of oio^oo (1 inch = nearly 4 mil 
ticular economic importance, cover 
the maps published are on a scale o: 
