Three
digital centreline
maps (A, C and E) of the same road.
Differential
GPS survey
(red) verifies that database C is most accurate.
Database A
has highly
generalized linework, but is relatively true, within 50 metres.
Database E
has spuriously
smooth arcs, but positions are in error by up to 200 metres.
Illustration
from DGRC
project at NCGIA, University of California, Santa
Barbara
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Geospatial Technologies in
Transportation
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