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Metadata
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ID
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B-L1-97-MU
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Also Known As
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VBLD
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Abstract
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University of Hawaii,United States Geological Survey, Menlo
Park, California. Chief Scientist: Bruce Richmond. Geodetic
survey data (geodetic, navigation) of field activity
B-L1-97-MU in Baldwin Beach Park NorthMaui, Hawaii from
01/08/1997 to 01/08/1997
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Organization
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University of Hawaii
United States Geological Survey, Menlo Park, California
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Project/Theme
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Hawaii Beach Monitoring Program
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Chief Scientist
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Bruce Richmond
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Activity Type
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Geodetic survey
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Platform
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Beach
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Area of Operation
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Baldwin Beach Park North
Maui, Hawaii
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Location map
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Bounding Coordinates
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20.91561
-156.38571 -156.38571
20.91561
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Dates
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01/08/1997 (JD 008) to 01/08/1997 (JD 008)
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Analog Materials
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No analog holdings.
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Index map
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Information Specialist
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Equipment Used
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Purpose
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Specific objectives include:
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a) document the magnitude and extent of the erosion problem;
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b) determine the individual causes for coastal erosion in the
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Hawaiian Islands and establish their relative importance;
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c) develop a coastal hazard database that can be applied to other
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studies; and
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d) provide input for predictive models on long-term coastal behavior.
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The overall objectives of the Hawaii
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Coastal Erosion Study are to document the recent history of shoreline
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change in Hawaii and to determine the primary factor(s) responsible
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for coastal erosion in low-latitude environments.
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This project will integrate studies
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of erosion history, large-scale coastal behavior, and the reef
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record to develop a comprehensive model of coastal-systems evolution
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with the goal of further enhancing our predictive capabilities
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regarding shoreline stability in important low-latitude environments.
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It is anticipated that results from this project can be applied
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to low-latitude shorelines around the globe.
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In an effort to establish baseline beach conditions, monitor
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seasonal beach fluctuations, and understand the dynamics of beach
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change in Hawaii, a program of beach and nearshore monitoring
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was initiated in 1994 on the islands of Maui and Oahu. Five years
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of biannual (approx. summer/winter) profiles on forty-two Oahu,
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and thirty-seven Maui, beaches have been collected to date. In
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order to address long-term change, we attempted to re-occupy
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beach monitoring sites established by University of Hawaii researchers
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during the early 1960s (Moberly and Chamberlain, 1964). However,
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determining the exact location of old profile sites proved difficult
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because of development along the coast and loss of the 1960s
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reference marks. All new sites are referenced to a common GPS
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network for accurate horizontal and vertical positioning.
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This data set is intended for scientific research of beach
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Morphology and volume changes.
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Information to be Derived
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The overall goals of this study are
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to document the coastal erosion
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history in Hawaii, determine the causal factors of that erosion,
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provide high-quality data for other "end-users" in
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applied studies (i.e. coastal engineers, planners, and managers),
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and increase our general understanding of low-latitude coastal
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geologic development. This project involves close cooperation
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between the USGS Coastal and Marine Geology Program and the University
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of Hawaii.
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The data and results are presented as a web site (a separate
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CDROM is also available). For the islands of Oahu and Maui,
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Index maps show the location of the beach profile
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monitoring sites. Each site is linked to a site map, photograph
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of the area, collection of beach profiles, and the profile data.
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Summary
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Biannual beach profiles
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were collected at 42 Oahu and 36 Maui
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locations between August 1994 and August 1999. Surveys were
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conducted at approximately summer-winter intervals and extend
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from landward of the active beach to about -4 meters water depth.
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Profile data on a CDROM are presented in both Microsoft EXCEL
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97/98 & 5.0/95 Workbook (.xls) format and comma separated value
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(.csv) format. Graphical representation of the surveys (x vs. z and
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x vs. y) are presented in EXCEL format only. Site descriptions,
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including beach location, directions to site, GPS information,
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and a description of Reference Points used, are available in both
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EXCEL and ADOBE ACROBAT .pdf format.
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Coastal erosion is widespread and
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locally severe in Hawaii and other low-latitude areas. Typical
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erosion rates in Hawaii are in the range of 15 to 30 cm/yr (0.5
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to 1 ft/yr; Hwang, 1981; Sea Engineering, Inc., 1988; Makai Ocean
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Engineering, Inc. and Sea Engineering, Inc.,1991). Recent studies
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on Oahu (Fletcher et al., 1997; Coyne et al., 1996) have shown
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that nearly 24%, or 27.5 km (17.1 mi) of an original 115 km (71.6
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mi) of sandy shoreline (1940's) has been either significantly
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narrowed (17.2 km; 10.7 mi) or lost (10.3 km; 6.4 mi). Nearly
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one-quarter of the islands' beaches have been significantly degraded
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over the last half-century and all shorelines have been affected
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to some degree. Oahu shorelines are by far the most studied,
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however, beach loss has been identified on the other islands
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as well, with nearly 13 km (8 mi) of beach likely lost due to
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shoreline hardening on Maui (Makai Engineering, Inc. and Sea
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Engineering, Inc., 1991).
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Causes of coastal erosion and beach loss in Hawaii are numerous
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but, unfortunately, poorly understood and rarely quantified.
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Construction of shoreline protection structures limits coastal
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land loss, but does not alleviate beach loss and may actually
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accelerate the problem by prohibiting sediment deposition in
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front of the structures. Other factors contributing to beach
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loss include: a) reduced sediment supply; b) large storms; and,
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c) sea-level rise. Reduction in sand supply, either from landward
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or seaward (primarily reef) sources, can have a myriad of causes.
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Obvious causes such as beach sand mining and emplacement of structures
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that interrupt natural sediment transport pathways or prevent
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access to backbeach sand deposits, remove sediment from the active
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littoral system. More complex issues of sediment supply can be
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related to reef health and carbonate production which, in turn,
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may be linked to changes in water quality. Second, the accumulated
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effect of large storms is to transport sediment beyond the littoral
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system. Third, rising sea level leads to a natural landward migration
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of the shoreline.
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Dramatic examples of coastal erosion, such as houses and roads
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falling into the sea, are rare in Hawaii, but the impact of erosion
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is still very serious. The signs of erosion are much more subtle
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and typically start as a "temporary" hardening structure
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designed to mitigate an immediate problem which, eventually,
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results in a proliferation of structures along a stretch of coast.
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The natural ability of the sandy shoreline to respond to changes
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in wave climate is lost.
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Notes
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Other field activities at Baldwin Beach Park North
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on Maui also have Activity IDs beginning with "B-L" and ending with "-MU"
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Cross-shore beach profile data were collected as a component of
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the Hawaii Coastal Erosion Study, a cooperative effort by U.S.
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Geological Survey and University of Hawaii in order to document
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seasonal and longer-term variations in beach volume and behavior.
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The overall objectives of the Hawaii Coastal Erosion Study are to
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document the recent history of shoreline change in Hawaii and to
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determine the primary factor(s) responsible for coastal erosion
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in low-latitude environments for the purpose of predicting future
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changes and to provide quality scientific data that is useful to
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other scientists, planners, engineers, and coastal managers.
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The overall strategy consists of first quantifying the magnitude
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and location of serious erosion problems followed by close monitoring
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of coastal change in critical areas. Bi-annual beach profiles have
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been collected at over 40 critical beach sites on the islands of Oahu
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and Maui. Once sufficient background information is analyzed and key
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problems are defined, field sites will be selected for detailed process-
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oriented studies (both physical and biological) to gain an understanding
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of the complex relationships between reef carbonate production, sediment
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dispersal, and the interaction of man-made structures with sediment
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movement along the shore.
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Information derived from this project will be used to develop general
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guidelines for sediment production, transport, and deposition of low-
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latitude coasts. Planned major products include a comprehensive atlas of
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coastal hazards, journal articles and reports presenting results of our
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studies, and a "living" database of shoreline history and changes based
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on results of the beach profile monitoring and softcopy photogrammetric
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analysis.
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Cross shore beach profiles were measured using a Geodimeter
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464 total station and swimming rodman. The total station was
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set up at a non-specific position on the beach. Up to five
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permanent reference points were first surveyed in order to
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establish the position of the station relative to the established
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profile line. Beach profile measurements were then taken from
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a point landward of the active beach to as far offshore as
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conditions would allow (typically -4m water depth). Specific
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morphologic features (high water, berm crest, top of beach toe,
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etc.) were noted. Data were post-processed as follows Survey data
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were downloaded from the Total Station memory, automatically
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creating a RAW file and an associated JOB file. The RAW file
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was used to generate a PTS file (UTM field coordinates are
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extracted from the RAW file) Note: no recalculation is performed
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on the original file). PFCODE.EXE was used on the JOB file to
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generate an ED file. The ED file was edited to include necessary
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Program 10 information, Points block listing, and INFO codes.
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Field procedures were checked and corrected as necessary.
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PFGD.EXE was used on the ED file to generate a PF file (Cartesian-
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based, relative XYZ coordinates). Extraneous lines were removed
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from the PF file to generate a DAT file (relative XYZ coordinates) DAT
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files were compiled into a SUMMARY file (Excel) format, plotted,
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and where necessary, corrected relative to a primary reference point.
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Where GPS positions of the reference points were available, the entire
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summary file was re-referenced to an absolute vertical elevation
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(meters above the Local Hawaii Tidal datum).
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Got Help?
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For B-L1-97-MU, we would appreciate any information on -- crew, information to be derived, equipment used, information specialist, ports, publications, purpose, summary.
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