Digital Orthophoto Background Information
The National Digital Orthophoto Program is a joint effort by the U.S. Geological Survey,
the U.S. Forest Service and the U.S. Department of Agriculture’s Natural Resource
Conservation Service (NRCS) and Farm Service Agency (FSA) to ensure public domain
availability of digital orthophoto quadrangle (DOQ) data for the nation. There are
currently over 50,000 digital orthophotos available for distribution and complete digital
orthophoto coverage for the coterminous United States is expected by 2004. The DOQs
will be updated on a ten-year cycle for most areas and a five-year cycle for areas that
undergo rapid rates of land use change.
Digital orthophotos come in quadrangle or quarter-quadrangle units and combine the
image characteristics of photographs with the geometric qualities of a map. They are
produced from aerial photography by removing the effects of camera tilt and relief
displacement to provide a planimetric base with true ground position. This rectification
process produces geographically correct digital images which can then be used for direct
measurement of distance, areas, angles and positions. Because digital orthophotos display
features that may be omitted or generalized on maps they are often used as a background
layer in a geographical information system to provide a context for other data layers.
Digital orthophotos are further used as interim maps, as field references for Earth Science
investigations and as tools that support decision-making processes and spatial analyses.
The digital orthophoto quarter-quad (DOQQ) is the largest scale format available in the
National Digital Orthophoto Program. It has a one meter ground resolution and covers an
area of 3.75 minutes of longitude by 3.75 minutes of latitude at a scale of 1:12 000. In
comparison the digital orthophoto quadrangle has a 2 meter ground resolution and covers
an area of 7.5 minutes of longitude by 7.5 minutes of latitude at a scale of 1:24 000. The
digital orthophotos come with 50-300 meters of overedge to facilitate edgematching and
mosaicking of images for integration into a common coverage.
(Sources: USGS Global Land Information System Website, Digital Orthophoto Quadrangles page:
(http://edcwww.cr.usgs.gov/Webglis/glisbin/guide.pl/glis/hyper/guide/usgs_doq) and USGS DOQQ
metadata document doqsti.txt.)
Digital Orthophotos for Lake Michigan Coastal Counties
Summary of Coverage by County:
Marinette
7% (10 of 142) of DOQQ coverage is available, mostly overlap from other counties in the northwest edge
of the county. Four orthophotos do exist for the eastern coastal area that we are interested in. There have
been discussions with NRCS, Bay-Lake RPC and private contractors to examine the feasibility of
orthophotos.
Nine orthophotos are needed for coastal coverage along the 1000-meter zone (given below as Quadrangle
Name– Quadrangle Quadrant):
Marinette East-NW
Marinette East-SW
Marinette East-SE
Green Island-SW
Oconto East-NE
Peshtigo Harbor-NE
Peshtigo Harbor-NW
Marinette West-NE
Marinette West-SE
Those orthophotos that are available as part of the current USGS DOQQ coverage are indicated in bold
type. We currently do not have copies of these available DOQQs on hand or on order.
Oconto
5% (5 of 108) of DOQQ coverage is available along the southern edge of the county where it overlaps
orthophoto coverage for Brown County. There has been a meeting at Bay-Lake RPC to discuss orthophoto
creation.
Eleven orthophotos are needed for coastal coverage along the 1000-meter zone (given below as Quadrangle
Name– Quadrangle Quadrant):
Suamico-SE
Little Tail Point-SW
Little Tail Point-NW
Pensaukee-NE
Pensaukee-SW
Oconto Southeast-NW
Oconto East-NW
Oconto East-NE
Oconto East-SW
Pensaukee-SE
Suamico-NE
Those orthophotos that area available as part of the current USGS DOQQ coverage are indicated in bold
type. We do have orthophoto coverage for both Suamico-SE and Little Tail Point-SW on the Brown
County USGS CD.
Brown
Brown County DOQQ coverage is complete and available from the USGS. We have a copy of the complete
USGS DOQQ coverage on CD-ROM.
Thirteen orthophotos are needed for coastal coverage along the 1000-meter zone (given below as
Quadrangle Name– Quadrangle Quadrant):
Dyckesville-SE
Dyckesville-SW
Little Tail Point-SW
Green Bay East-NE
Green Bay East-SE
Green Bay East-SW
Green Bay East-NW
New Franken-NE
New Franken-NW
Suamico-SE
Green Bay West-NE
Green Bay West-NW
Green Bay West-SE
Kewaunee
No coverage is available at the time of this writing according to searches carried out on the U.S. Geological
Survey’s Global Land Information System. DOQQs have been authorized and are currently in production.
Nine orthophotos are needed for coastal coverage along the 1000-meter zone (given as Quadrangle Name–
Quadrangle Quadrant):
Algoma-NW
Algoma-NE
Algoma-SW
Dyckesville-SE
Kewaunee-NE(extends east to
include coastline east of quad?)
Namur-SW
Two Creeks-NE
Forestville-SE
Kewaunee-SE
Those orthophotos indicated in bold type are currently in our possession from overlap with other counties.
Door
Door County DOQQ coverage is complete and available from the USGS. We currently have partial
coverage on writable CD burned from tapes given to us by the NRCS.
Sixty-two orthophotos are needed for coastal coverage along the 1000-meter zone (given below as
Quadrangle Name– Quadrangle Quadrant):
Algoma Northeast-NW
Algoma Northeast-SW
Baileys Harbor East-NE
Baileys Harbor East-NW
Baileys Harbor East-SW
Baileys Harbor West-NE
Baileys Harbor West-NW
Baileys Harbor West-SE
Chambers Island-NW
Chambers Island-SE
Chambers Island-SW
Chambers Island NW-NE
Chambers Island NW-SE
Egg Harbor-NE
Egg Harbor-NW
Egg Harbor-SE
Egg Harbor-SW
Ellison Bay-SE
Ellison Bay-SW
Ephraim-NE
Namur-NW
Ephraim-SE
Ephraim-SW
Forestville-NE
Forestville-SE
Idlewild-NE
Idlewild-SE
Idlewild-SW
Institute-NW
Institute-SW
Jacksonport-NE
Jacksonport-NW
Jacksonport-SE
Jacksonport-SW
Jacksonport SW-NW
Little Sturgeon-NE
Little Sturgeon-NW
Little Sturgeon-SW
Little Sturgeon SW-SE
Little Sturgeon SW-SW
Namur-NE
Namur-SW
Sister Bay-NE
Sister Bay-NW
Sister Bay-SE
Sister Bay-SW
Spider Island-NW
Sturgeon Bay East-NE
Sturgeon Bay East-NW
Sturgeon Bay East-SE
Sturgeon Bay East-SW
Sturgeon Bay West-NE
Sturgeon Bay West-NW
Washington Island NE-SE
Washington Island NE-SW
Washington Island NW-SE
Washington Island NW-SW
Washington Island SE-NW
Washington Island SW-NE
Washington Island SW-NW
Washington Island SW-SE
Washington Island SW-SW
The orthophoto names in bold are those that we currently have on writable CD from NRCS. The
underlined orthophoto quarter-quads are those that are currently being sent to us by the NRCS.
The first determination of coverage was based on visual examination of the Index to U.S. Geological
Survey’s Topographic Maps of Wisconsin. A more accurate assessment was given by doing a GIS
intersection query with the 1000-meter buffered zone and the quarter-quadrangle overlay. This operation
revealed that there are additional orthophotos which come just within the 1000-meter coastal zone. Thus
these additional orthophotos will need to be obtained (They are also indicated in the above list as text
without underlines or boldface):
Egg Harbor-NW
Forestville-NE
Jacksonport-SE
Little Sturgeon-SW
Forestville-SE
Namur-NE
Chambers Island NW-NE
Chambers Island NW-SE
Manitowoc
Manitowoc County DOQQ coverage is complete and available from the USGS. We currently have
complete coverage on a USGS CD and also some duplicate coverage on a writable CD burned from tapes
given to us by the NRCS.
Eleven orthophotos are needed for coastal coverage along the 1000-meter zone (given as Quadrangle
Name– Quadrangle Quadrant):
Cleveland East-SW
Cleveland East-NW
Manitowoc-SW
Manitowoc-SE
Manitowoc-NE
Mishicot-SE
Two Creeks-SE
Two Creeks-NE
Two Rivers-NE
Two Rivers-SE
Two Rivers-SW
Sheboygan
Sheboygan County DOQQ coverage is complete and available from the USGS. We currently have almost
complete coverage of the USGS DOQQs on a writable CD burned from tapes given to us by the NRCS.
We are missing Sheboygan Falls-SE however.
Eight orthophotos are needed for coastal coverage along the 1000-meter zone (given as Quadrangle Name–
Quadrangle Quadrant):
Cedar Grove-SE
Cedar Grove-NE
Cleveland East-SW
Sheboygan Falls-SE
Sheboygan North-SW
Sheboygan North-NW
Sheboygan South-SW
Sheboygan South-NW
Ozaukee
We have the complete coverage of SEWRPC orthophotos for Ozaukee County. They also have 1956
orthophotos from a coastal recession study area (the southern 10 miles of the county).
Milwaukee
Complete coverage is available from SEWRPC orthophotos. We still need to obtain these.
Racine
Complete coverage is available from SEWRPC orthophotos. We still need to obtain these.
Kenosha
Complete coverage is available from SEWRPC orthophotos. We still need to obtain these.
Estimated Completion Costs of Digital Orthophoto Quarter-Quad Production
The costs of orthophoto production are sometimes shared with agencies interested in seeing the completion
of orthophoto coverage for a given area. According to Ted Koch of the State Cartographer’s Office those
agencies involved in cost-sharing of the production of DOQQs usually put up enough funds to cover half
the cost of orthophoto production. He estimated this figure to be $1020 per orthophoto quarter-quadrangle.
So the total cost per unit for orthophoto quarter-quadrangle production is about $2040. He did mention that
this figure does not represent total production costs. Additional fiscal resources may be required if a photo
source does not already exist for the area (usually the NAPP 1:40 000 series) or if additional control
information is required. If additional ground control information is needed the added cost would include
sending survey crews to collect the information. He also mentioned that with the beginning of the new
federal fiscal year in October of 1998 the cost of orthophoto production would probably lower to less than
$2000 per quarter-quadrangle.
Based on the cost estimates given above I have estimated the completion costs for Oconto and Marinette
counties.
Estimate of Completion Costs for Marinette County:
There are 142 orthophoto quarter-quadrangles in Marinette County.
The estimated total cost of production of 142 orthophotos is:
142 photos * $2040/photo = about $290,000.00
Estimate of Completion Costs for Oconto County:
There are 108 orthophoto quarter-quadrangles in Oconto County.
The estimated total cost of production of 108 orthophoto is:
108 photos*$2040/photo = about $ 220,000.00
Digital Orthophotos Specifications
USGS
Date:
1992
Naming convention:
O4408743.nwh
O4408743.nwc
O – orthophotoquad
nw – quarter of quadrangle
c – compressed (JPEG format)
h – header file (ASCII)
Oyyxxxzz.nwh
yy- SE Latitude of 1 degree block in which quad resides.
xxx- SE Longitude of 1 degree block in which quad resides.
Format:
JPEG
File Size:
Approximately 55MB uncompressed, approximately 2.6-3.5MB
JPEG compressed.
Scale:
1:12 000, 1 meter ground resolution.
3.75 min. longitude by 3.75 min. latitude quarter quadrangle.
Projection and
Coordinate System:
Universal Transverse Mercator, coordinates from NAD83.
Coordinates in meters.
NAD83 and NAD27 quarter quad ticks are embedded in the image.
Accuracy:
Orthophoto quarter quads meets National Map Accuracy Standards for
1:12 000 scale.
Availability:
Available from USGS in the following formats:
-CD (recordable), 45-50 MB uncompressed, $40
-CD-ROM (quadrangle), 5MB/file (JPEG compressed), $32/1 CD, $42/2 CDs,
$52/3 CDs
-ftp (quarter quadrangle), 45-50 MB uncompressed, $40, volume pricing exists
-8mm tape (quarter quadrangle), 45-50 MB, $40, volume pricing.
Data Access:
USGS DOQQs are available from the USGS Global Land Information System.
Sharing Policies:
Public access priced at cost of distribution.
NRCS
Date:
1992
Naming convention:
Q4586d83.bil
Q4586d83.hdr
-the last digit refers to quarter of quad
1 NW NE 2
4 SW SE 3
-the numbering system for the files was not described in the metadata
Format:
.bil
File Size:
41-42MB
Scale:
1:12,000
Projection and
Coordinate System:
see USGS information above.
Accuracy:
see USGS information above.
SEWRPC
Date:
1995
Naming convention:
ttrraa.EXT
“ttrraa” describes the geographic coverage of the orthophoto file, where:
tt = township identifier (including a leading zero, if applicable)
rr = range identifier
aa = aerial photo identifier
Format:
.TIF
File Size:
?
Scale:
? 1:4 800 (1”=400’), 2 foot pixel resolution.
A single orthophoto image covers a nominal four-square-mile area representing
four US Public Land Survey sections.
Projection and
Coordinate System:
Wisonsin Coordinate System, South Zone, NAD27.
Accuracy:
?
Availability:
Available from SEWRPC
Data Access:
$100/CD. CD covers a survey township.
There are 73 master CDs for the 7 county SEWRPC area.
Sharing Policies:
?