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airplanes, boats, highway and railroad 
vehicles to be “mobile” vehicles. 
Therefore, since the accuracy 
requirements are satisfied by such 
mobile platforms there is only the 
question of economics. 
Locating a feature (e.g., an electric 
pole) to £ 0. 1 m. by traditional 
surveying techniques costs between 
five dollars and two hundred dollars 
depending on factors such as numbers 
of features, length of traverse, distance 
to reference control, etc. With mobile 
mapping systems an “apple to apple” 
comparison yields reductions in cost of 
factors of two to fifty. Therefore, | 
assert that at least consideration 
should be given to directly acquiring 
current accurate digital data rather 
than digitizing old inaccurate maps. 
The use of digital cameras provides 
enormous additional benefits such as 
the ability to keep the data in a 
database, retrieve it at will and 
measure something that was not 
interesting at the time the project was 
accomplished. 
The applications of this history file in 
digital form, are limited primarily by our 
imagination. 
Incentives for Sharing Data 
A number of incentives for data 
sharing and other forms of 
cooperation, which will obviously 
enhance usage, appear to have 
worked--and in some cases very well. 
For example, Richard Yorczych of the 
Horizontal Network Branch of the 
National Geodetic Survey (NGS) 
reports that they have received data 
from other organizations for 65,000 
horizontal geodetic control points since 
1980 (Yorczych, 1992). This data 
donor program works because the 
donors (state, county, and private 
organizations) want to assure the 
accuracy of the points they observed 
159 
developed by the state. 
and earn a stamp of approval from the 
nation’s highest authority on geodetic 
control. It was essential that the NGS 
develop a standard in order to 
implement this mechanism. This 
standard for submitting geodetic 
information to NGS is known in the 
vernacular as the “Blue Book” (U.S. 
Department of Commerce 1980, U.S. 
Department of Commerce 1988). The 
cost of these data can be 
conservatively estimated at 65,000 x 
$1,000/point = $65,000,000. The 
value of such data was the subject of a 
study by Epstein and Duchesneau, 
1984, and while cost and value are not 
always equal, they are generally 
positively correlated. 
One of the best examples of a 
successful incentive program at the 
state level can be found in North 
Carolina (Holloway, 1986). Ten years 
ago, North Carolina began providing 
seed money to counties that followed 
certain mapping and other standards 
These 
standards in turn comply with federal 
standards. As far as | know, every 
county in North Carolina has taken 
advantage of this program. Since the 
amount of funding given to each 
county is small, it appears that money 
may not be the only motivating factor, 
and that other less tangible factors like 
those mentioned in the preceding 
paragraph are important. 
CONCLUSIONS 
Spatial data and information are in 
demand and are being increasingly 
used to satisfy the hungry appetites of 
GIS. The most important data sets 
are, apparently geodetic control, digital 
orthophoto, street centerlines, parcel 
boundaries, land use and hydrological 
data. Accuracy and quality of data is 
important but should be viewed from a 
user of spatial data perspective not