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in his survey of deeper areas.  Natural-color film has shown the greatest 
water penetration of the emulsions tested, reaching depths of 75 feet 
in clear water, decreasing to 5 to 10 feet in turbid coastal water. 
Tests using false-color infrared emulsion showed clear water penetration 
to depths near 25 feet. Bottom features are somewhat less defined 
as compared to natural color. 
SOIL CONSERVATION SERVICE 
Jerome A. Gockowski 
Soil surveys and published soil maps in the National Cooperative 
Soil Survey program are prepared in cooperation with state agricultural 
experiment stations and other State and Federal agencies. Since 1956 
all soil maps have been published with an aerial photographic background. 
In the period January 1, 1972 to January 1, 1976, SCS contracted for 
aerial photography govering 725,000 km“, and soil maps for 329 areas 
covering 682,000 km" were published. The standard scale for soil 
maps is 1:20,000, but detailed maps are also published at 1:15,840, 
and a few have been published at 1:24,000 and 1:31,680. 
In areas where relief is less than 100 m within a radius of 
2 km of any point, SCS uses rectified enlargements from center 
portions of individual exposures from high altitude aerial surveys. 
For areas where relief is excessive, SCS has cost-sharing agreements 
with the USGS for production of orthophotos. Between 1974, when the 
orthophoto program was started, and January 1976, a total of 3760 
quadrangles covering 621,000 km? has been contracted to USGS. 
The SCS has a requirement for 1:100,000-scale planimetric base 
maps on a county format. These are also produced by USGS on a cost- 
sharing agreement. Since June 1975, approximately 120 county maps 
have been authorized. 
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