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Case
Study |
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Dane County participated in a federal GIS
demonstration project (OrthoFinder) with the
Wisconsin State Cartographer's Office,
University of Wisconsin-Madison, Wisconsin
Dept. of Natural Resources, the City of
Madison, and Ayres Associates. The project
investigated issues related to the
discovery, access and use of digital
orthophotography acquired by different
agencies, at different times, over the same
geography. Dane County was selected because
of its 15-year history of orthophotography
projects. The Fly Dane 2000 project was
reviewed as a case study for others who want
to learn about digital ortho acquisition,
project planning, institutional and policy
issues, and partnership and collaboration
opportunities. To learn more about the
OrthoFinder tool or project, please visit
the
State Cartographers Office. |
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Fly
Dane 2000
Orthophotography Project
Modern technology makes it possible to
produce a wide range of digital mapping
products; orthoimagery is one such
product that public agencies, private
businesses, and others have increasingly
utilized in the last decade. As digital
mapping tools have developed, the
landscapes being photographed and mapped
have also been continually (and often
rapidly) changing. This dynamic – of
improving technology and changing land
resources – makes it important, for
users in both government and business,
to routinely update digital imagery and
the products created from such imagery.
It is not an easy task to create and
maintain up-to-date digital orthoimagery.
It is expensive, time consuming, and
technically challenging to plan,
acquire, and process aerial photos,
create the mapping products, and manage
their distribution. Public agencies or
local units of government seldom have
the resources to commit to such a
project on their own -- nor can
individual private businesses afford the
large investment. The dilemma is that
it's costly in terms of time and money,
but it increasingly benefits many
parties (in both the public and private
sector). The challenge is to develop
strategies to share in the investment in
order to make the work possible.
There is no single right answer to how
to pool resources to do orthophotography
projects. They vary in their broad scope
and their myriad details -- and the
technology is so new that a common
project "framework" has not yet emerged.
Valuable experience has been acquired in
recent years, however, as Wisconsin
counties and other local units of
government have created a number of
consortiums to acquire and process
aerial imagery. One recent project --
called "Fly
Dane 2000" -- is an example of a
successful partnership model that holds
great promise for future work. |
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Why
look at FlyDane?
Fly Dane
offers a good case study of a
cooperative, locally-funded
orthophotography project for several
reasons:
-
It has been an
ambitious effort that has included an
unusually large number of partners.
This has been managerially (and
politically) challenging, but also has
helped make the project successful.
-
It is part of an
ongoing effort to regularly acquire
imagery and update products -- an
approach that is preferable to a
one-time project, because the
technology and environment being
mapped are continually changing and
the applications for this type of data
continue to emerge.
-
It illustrates
some of the fiscal challenges faced by
such projects, and it offers some ways
to creatively deal with them.
-
It
illustrates some of the complex issues
related to product distribution,
including distribution methods,
pricing, and public availability.
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Fly
Dane Goals
Fly Dane
2000 was a collaborative effort among
Dane County government, numerous county
municipalities, and private partners to:
- Acquire
updated aerial imagery for a
census-year view of the county;
- Utilize the
updated imagery and terrain data to
produce more detailed and accurate
mapping products than had been
previously available; and
- Establish a
long-term partnership to assure that
the data was regularly updated and
maintained.
An equally
important goal and by-product of the
project was to upgrade the County's
survey control network. The network was
inventoried and additional horizontal
and vertical control was established to
enhance the network and provide an
improved framework for a new terrain
model and aerial photography. The data
was later "bluebooked" (catalogued with
the National Geodetic Survey) and used
to develop a new survey data management
system for the County Surveyor. |
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Fly Dane Participants
A total of
forty-three project partners
collaborated in Fly Dane 2000, including
Dane County, the Regional Planning
Commission and Metropolitan Planning
Organization, 24 cities and villages, 15
towns, state and federal agencies,
utilities, and a private business. The
Dane County Land Information Office
acted as the project coordinator;
Fairview Industries assisted with
project definition and alternatives, RFP
development, and survey services; and
Ayres Associates (a Madison-based
photogrammetric mapping and engineering
firm) was contracted to assist with
partnership development and project
deliverables.
It is
important to emphasize the collaborative
nature of Fly Dane. It was not designed
as a County project, but rather as a
partnership meant to benefit many
contributors. The large number of
participants and the evolution of
contracted services to cover additional
local services indicates that area-wide
data needs were being addressed. The Fly
Dane partnership is open and ongoing
with new partners continuing to join. |
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Forming
a Partnership
This kind
of collaboration obviously doesn't just
"happen" without a great deal of effort.
It requires support from local political
leaders, careful project planning,
organizational and managerial skills on
the part of project coordinators, and an
active commitment from the project
partners. These organizational factors
are all important because of the
multi-year nature of the project, its
technical complexity, and the number of
parties involved.
Initially Dane
County considered a single agency
project that would have used the older
terrain model to produce updated 1/2
meter resolution imagery. The County
could afford to fund this type of
project on its own, but it would not
have met county needs for an improved
terrain model to support FEMA floodplain
mapping, a new soils survey, stormwater
management, and other projects.
Municipalities also needed a more
accurate terrain model and imagery for
utility mapping and the development of
2' contours for engineering work. The
1997 City of Madison orthophoto project
had already demonstrated the value of
this additional detail and accuracy at
the municipal level. Neighboring
municipalities were interested in
improved terrain and image products but
could not afford to acquire this data on
their own. The partnership enabled them
to get beyond budget limitations and the
high cost of individual projects.
The Dane County
Land Information Office and Ayres
Associates began contacting potential
partners early in the process. This was
essential both to ensure their full
commitment and participation and to
enable partners to plan and budget for
the project during their normal budget
cycle.
Dane County and
Ayres spent over a year meeting with
local municipal staff and elected
officials to explain the project. For
each meeting, a CD was prepared with
sample high resolution data, viewing
software, and documents describing the
project, partner options, and funding
arrangements. This CD was left with the
municipality to share with other staff
and elected officials. Sample hard copy
plots showed the difference between the
1995 1-meter imagery and the proposed
2000 1-foot and 6-inch image products.
Information describing pre-flight
targeting methods and materials were
developed for discussions about utility
mapping.
With many partners,
Dane County and Ayres were able to
demonstrate the value of the proposed
products for projects and issues before
them. One community had acquired
planimetric data in the past, but had no
digital copies in-house. They needed to
contact the previous vendor every time
they needed additional hard copy prints.
This municipality was interested in
acquiring 6" imagery so they could
update planimetrics in the future and
have it available in-house. A few months
later, contract arrangements made it
possible for them to develop the
planimetric data as part of the Fly Dane
project. Another community faced
repeated flooding issues in a particular
area and was interested in detailed
terrain data to help with FEMA
floodplain studies. Another local
engineering firm that provided
engineering services to several of the
communities saw the value of this
project for its clients. It would be
faster and cheaper for communities to
acquire some of the needed data
throughout the Fly Dane project, leaving
the engineering firm to concentrate on
enhancing the partnership products and
providing other engineering services.
Many communities
commented that this project represented
just what the County should do to help
them. Individually, communities were
struggling with data acquisition costs.
Many were just on the verge of
implementing GIS and knew they would
need this data, but it is often
difficult to convince elected officials
to commit to an emerging need. The
County's ability to step forward in a
coordinating role allowed communities to
overcome budget limitations and justify
the investment and timing to local
officials.
Municipalities were
particularly interested in better data
to support floodplain determinations and
appeals, engineering projects, and land
use planning. (New Smart Growth
legislation had just been passed in
Wisconsin requiring all municipalities
to develop comprehensive land use
plans.) As the County became more
familiar with the municipal needs,
arrangements were made with Ayres to
expand contracted services to allow
individual municipalities to develop a
denser terrain model to support higher
resolution imagery and the development
of planimetric and 2' contour data.
Partners
were kept updated on the project and
partnership's development though status
reports, partner meetings, and a
project web site.
"Selling"
the project was made easier by the fact
that it was structured as a true
partnership -- it was voluntary,
flexible in terms of meeting the
partners' diverse needs and interests,
and cost-effective. The "economies of
scale" created by the partnership
approach made it possible to greatly
reduce the costs (in comparison to
"go-it-alone" projects) and take
advantage of those savings to create
higher-quality products. Partners were
also attracted to the long-term
arrangements that would help assure the
products would be updated and funded in
future years. Partners helped establish
product prices that balance data access
and availability with the upfront
investment needed to make the project
happen. |
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Fly
Dane Planning and Implementation
Fly Dane
was not Dane County's first
orthophotography project. In 1995, Dane
County participated in a seven-county
consortium that worked with Ayres
Associates to create 1-meter resolution
ortho imagery and data collections of
10-foot contours, road centerlines, and
hydrologic features.
Planning for Fly
Dane 2000 began in the fall of 1998.
There was a general consensus that the
1995 products needed to be improved
upon, so the County asked Fairview
Industries to help develop a Request For
Proposal (RFP) that would assure
creative options and alternatives
(including partnerships) in the proposal
responses.
It was evident from
the start that Ayres understood project
needs and the special arrangements and
commitment a partner project would
require. The firm saw the benefits of a
broader partnership and believed the
extra efforts would be worth their
investment as well as that of the
partners. As a result, Ayres outlined
the following as project guidelines:
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The County
required higher resolution imagery for
most of its applications.
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Cities and
Villages required much higher
resolution imagery for their
applications.
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A mix of
accuracies, resolutions, and products
was needed.
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Opportunities
existed for a partnership approach.
Ayres then
identified some specific ways to improve
upon the 1995 products:
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Create
higher-resolution orthos, including
6-inch resolution in urban and
urbanizing areas and 1-foot resolution
for the remainder of the county.
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Create a new
terrain model, with a 2-foot vertical
accuracy that would support
development of four-foot contours.
In addition, the
project would include these products:
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Densification and
adjustment of the survey control
network
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A survey control
inventory and database
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A digital road
centerline dataset
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A digital
hydrography data set
As noted,
planning for Fly Dane began in the fall
of 1998. In the spring of 1999, the
County selected Ayres Associates as the
primary vendor. Project staff from Dane
County and Ayres Associates continued
project preparations through 1999 and
the first few months of 2000. By January
2000, the partnerships had been
established and the first partnership
meetings were initiated. Geodetic and
survey photo control were established in
February and March and aerial photos
taken in March and April 2000. Data
processing, quality control, and product
development followed the photo
acquisition and continued through the
first half of 2001. Imagery products
were delivered from January through July
2001. |
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Working
together to Develop the Best
An
important aspect of the Fly Dane project
was the close working relationship
between the contractor and the County on
quality control for the products.
Because of the huge dollar investment
the project represented and because the
work was accountable to so many
partners, the County decided to conduct
a second level of review on the
deliverables. As imagery came in from
Ayres, Dane County staff used an ArcView
application to review the imagery for
large dust spots or scratches, ghosting,
and warping. An ArcView shapefile was
generated noting the location and type
of problem found. Ayres staff was able
to quickly review the ArcView file and
correct any problems with the imagery.
Generally, imagery was reviewed,
returned, corrected, and sent back to
the County within five business days and
caused no delay to the project schedule.
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 field engineering records.
Where problems were found, Ayres quickly
corrected the underlying terrain data
and contour development continued.
The review
process was beneficial to all parties,
provided additional quality assurance,
and automated processes in a manner that
was fast, efficient, and allowed
consistency between staff conducting the
review. |
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Products/Distribution
Fly Dane
2000 produced the following products for
its partnership. Partners have
countywide access to all project
deliverables; non-partners may purchase
the products through the Dane County
Land Information Office's normal data
distribution services.
-
1' resolution
imagery for the entire county
($200/quad section [4 sq. miles] tile)
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6" resolution
imagery in urban and urbanizing areas
($200/section [1 sq. mile] tile)
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4-foot contours
for the entire county
($200/quad-section [4 square miles]
tile)
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A countywide
Digital Elevation Model with a 2'
vertical accuracy and 10-foot grid
spacing ($600/quad-section [4 sq.
miles] tile)
Municipal partners
may also elect to produce additional
products from the data (such as 2'
contours or planimetrics.) In addition
to these products, other benefits
include densification and adjustments to
the survey control network, the
development of a survey control
inventory and database, and new digital
hydrography and road centerline data
sets.
Fly Dane imagery
has been re-sampled to meet federal (NDOP)
specifications (1-meter resolution) and
made available in the public domain
through the U.S. Geological Survey
Innovative Partnership program. The same
1-meter resolution imagery has been made
available in the OrbView Cities imagery
distribution program. Dane County will
receive a portion of the revenue from
each imagery sale via Orbimage's online
catalog.
All
proceeds from data sales are deposited
into the Fly Dane Reserve Fund and will
be used for future data updates. |
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Funding
Producing
high-resolution aerial imagery is
expensive. It was important for the
success of Fly Dane 2000 that project
costs be shared as widely and equitably
as possible. A long list of project
partners helped to fund the acquisition
and processing of the aerial imagery.
Expenditures for Fly Dane 2000 totaled
about $1.1 million. Partners contributed
to the project as shown below:
In addition,
because Fly Dane was formed to acquire
and routinely update aerial imagery, it
was important to create a funding
mechanism to help offset future costs.
For this reason, a Fly Dane Reserve Fund
was established in 2000, which consisted
of a segregated fund to hold proceeds of
sales of Fly Dane data products. This
fund will be used for support and
maintenance of current products and to
periodically acquire updated countywide
imagery.
It's important to
emphasize the economies of scale that
were realized by the partnership
approach. Ayres Associates, which has
performed many orthophotography projects
for both individual governments and
consortiums, has estimated that the
resulting products cost each partner
about 50% less than they would with
"go-it-alone" projects. If more
governments, agencies, and businesses
that benefit from this work are
persuaded to become contributing
partners, per-partner costs can be
further reduced -- and perhaps more
products can be offered.
Much of this work
is an investment that is not only repaid
by the substantial benefits it produces,
but also by the decreased costs of
acquiring and processing imagery in the
future. For example, using the more
detailed Digital Terrain Model created
by Fly Dane 2000 will result in
significant savings when imagery is
re-acquired, currently scheduled for
2005. So, money that is well-spent now
can result in future savings. |
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Applications
of Fly Dane 2000 Products
Orthoimagery and the terrain model
created for the imagery are useful for a
variety of applications, some of which
are categorized below. For more
discussion about orthophoto uses and
applications, go to the
State Cartographers Office
website. Products from the project are
being used as base image maps to display
the following information:
- General land
use planning
- Public
information products
- Census
geography
- Geometric
feature representation to +/- 10 feet
(hydrographic and road centerlines)
- Development
of modernized soil surveys
- Utility
mapping
- Preliminary
engineering studies (at the municipal
level)
Products from the
project are being used as source maps
for the following projects:
- FEMA
floodplain/floodzone delineation and
floodplain/floodzone mapping
- Wetland
identification
- Slope
determination
- Stormwater
planning
- Countywide
land use inventory
- Environmental
corridor and open space corridor
delineation
Site
planning
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Fly
Dane Summary and Conclusion
In the
introduction, we spoke of the benefits
of regularly acquiring orthoimagery. But
we also described the barriers to doing
so, particularly those faced by local
units of government -- including the
expense, the technical complexities, and
the political and managerial demands.
One way to overcome these difficulties
is to form partnerships that share the
work, the costs, and the benefits of
orthoimagery projects.
Partnerships are
especially attractive for
financially-strapped local governments
-- at a time when obtaining federal and
state assistance is increasingly
problematic. Various public
"consortiums" have been formed to do
orthoimagery projects in Wisconsin. Fly
Dane 2000 is a notable and successful
recent example.
A number of
conclusions and lessons can be drawn
from Fly Dane 2000:
- Fly Dane 2000
was a partnership in fact -- not just
"on paper". Partner participation was
actively encouraged in all phases of
the project. All partners benefit from
the work; to maximize those benefits,
it's important that they participate
in planning and implementation.
- There were
many project partners. Having many
"stakeholders" helped to spread the
cost among the many local governments
and agencies that will benefit from
the project.
- While the
active involvement of (and
contributions from) the partners was
critical, a project's success also
depends upon skilled, committed, and
sustained leadership -- which in this
case was provided by the Dane County
Land Information Office. This was not
a short-term commitment; planning
began in 1998, the products were
delivered in 2001, and follow-up work
continues to this day.
- The selection
of a vendor (or vendors) is obviously
also crucial to a project's success.
In the case of Fly Dane, Fairview
Industries and Ayres Associates
provided the required technical and
project management skills in all
phases -- from initial planning to
product delivery.
- Fly Dane 2000
partners envision the project as being
part of a long-term strategy to
regularly update orthoimagery and
associated products. Additional
partners continue to come in and it is
hoped that more partners will join as
the project's benefits become
increasingly apparent. The County
hopes that eventually all Dane County
communities and many other local
entities will be involved.
- An important
part of making Fly Dane 2000 an
immediate and ongoing success is the
development of funding mechanisms to
pay for current work and invest in
future work. It's important to
understand that the segregated fund
established for Fly Dane 2000 revenues
is not simply there to pay for past
and current work. Rather, the project
partners hope that a portion of
proceeds from contributions and
product sales will be viewed as an
investment in ongoing updates.
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