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The importance of robust quality assurance
and quality control for orthophotography and
related deliverables cannot be overstated.
An important aspect of the Fly Dane project
is the close working relationship between
the contractor and the County on quality
control. Because of the huge dollar
investment the project represents and
because the work is accountable to so many
partners, the County conducts a second level
of review on the project deliverables.
As imagery comes in from the contractor,
Dane County staff, using an ArcView
application, reviews the imagery for large
dust spots or scratches, ghosting, and
warping. An ArcView Shapefile is generated
noting the location and type of problem
found. This process allows the contractors
staff to quickly review the Shapefile and
correct any problems with the imagery.
Generally, imagery is reviewed, returned,
correct4ed, and sent back to the County
within five business days, causing no delay
to the project schedule.
In 2000, the terrain data was also reviewed
as part of the County's in-house development
of the countywide 4' contours. Data was
checked and compared to other county field
engineering records. Where problems were
found, the contractor correcte4d the
underlying terrain data.
The review process is beneficial to all
parties, provided additional quality
assurance and automated processes that
assure fast, efficient, and consistent
review. For fly Dane 2005, the County will
migrate the Ortho QA/QC Tool to the ArcGIS
platform. For more information about the QA/QC
process or automated tools used in the
process, contact
Fred Iausly.
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