Global Positioning System Reference
In-Depth Information
direction from the sun and stars and marked the boundary with wooden stakes
and hatchet marks on trees. Near Charlotte the proposed new state line, 150
feet south of the old one, would convert ninety-three South Carolina property
owners into North Carolina residents. Convenience store owners who would
be affected by the change say it would put them out of business because of
North Carolina's higher gas tax and ban on selling fireworks.142 142
Small improvements in precision multiplied over large distances, areas, or
volumes in a commercial enterprise can mean huge differences to the bottom
line. gps-enabled machine control has revolutionized such large-scale enter-
prises as agriculture, construction, dredging, excavation, grading, and paving.
In 1996 about 5 percent of farmers used gps precision to adapt cultivation
techniques to soil variability. 143 Instead of spreading seeds, irrigation, fertil-
izers, and herbicides uniformly across a field, they began managing these inputs
down to the square yard and eventually to fractions of an inch using row guid-
ance to avoid costly overlapping of applications. A farmer with 1,600 acres
could purchase a gps farming package from Rockwell or John Deere in 1996
for between $6,500 and $8,900 and save $16,000 on phosphorus and potash
alone in the first year. 144 By 2010 about 60 percent of farmers had adopted gps
systems. 145 The average unit price of gps agricultural equipment was around
$13,000, but farmers could cultivate more land with fewer tractors, operating
them around the clock in critical planting and harvesting months. 146 Analysts
estimate that gps reduces U.S. farmers' input costs by $9.8 billion annually
while generating improved yields worth $10.1 billion. 147 This $20 billion boost
to the U.S. agricultural industry amounts to roughly 12 percent of annual pro-
duction. 148 Some authorities believe precision farming will reach a 100 percent
adoption rate within five to ten years. 149
Trimble Navigation introduced SiteVision gps Grade Control in 1999, which
placed site plans on computer screens in bulldozer cabs, enabling operators to
excavate without surveyed stakes in the ground. 150 The technology, developed
in open-pit mining, lowered costs, saved time, and improved accuracy in large
road construction and land development projects. Precision three-dimensional
machine control today shaves waste and boosts profits in a variety of settings
where crews previously had to survey, set stakes, and run string lines to main-
tain proper elevations. At $50 per ton for asphalt, a contractor paving a ten-
mile road seventy-two feet wide can save $140,000 by pouring
one-one-hundredth of a foot less asphalt. 151 A landfill that charges a tipping
fee of $40 per ton can generate an extra $2 million of revenue and extend the
 
 
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