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Bench Mark Sheet for 8724328, CUDJOE KEY NO. POINT FL

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  4

                                                                                
Station ID: 8724328                         PUBLICATION DATE:  09/22/2003
Name:       CUDJOE KEY NO. POINT                              
            FL
NOAA Chart: 11434                           Latitude:   24° 42.0' N (  24.70000)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.3' W ( -81.50500)


To reach the tidal bench marks from the Catholic Church in Key West, FL proceed
33.0 km (20.7 mi) NE on U.S. Highway 1 to the junction of a paved road leading
north on Cudjoe Key, then 3.8 km (2.4 mi) north on the paved road to the U.S.
Air Force Radar Base.  The bench marks are located in the area around the base. 
The tide gage and staff were located on the U.S. Air Force Base pier.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  P 327 1970

MONUMENTATION:           Bench Mark disk                       VM#:         6949
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AA0161
SETTING CLASSIFICATION:  Concrete slab                         OPUS PID:        
LATITUDE:   24° 42.0' N (  24.70000)          LONGITUDE:  81° 30.3' W ( -81.50500)


The primary bench mark is a disk set on the top of the NE corner of a concrete
slab, 29.02 m (95.2 ft) west of and across the road from the NW corner of
Building 957, 8.69 m (28.5 ft) west of the centerline of the road, and level
with the ground.



                         BENCH MARK STAMPING:  Q 327 1970

MONUMENTATION:           Bench Mark disk                       VM#:         6950
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AA0162
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   24° 42.0' N (  24.70000)          LONGITUDE:  81° 30.3' W ( -81.50500)


The bench mark is a disk set on the top of the NW corner of a square concrete
base, 40 m (132 ft) NE of the NE corner of Building No. 928 (Power Plant), and
8.69 m (28.5 ft) east of the centerline of the road.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  4

                                                                                
Station ID: 8724328                         PUBLICATION DATE:  09/22/2003
Name:       CUDJOE KEY NO. POINT                              
            FL
NOAA Chart: 11434                           Latitude:   24° 42.0' N (  24.70000)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.3' W ( -81.50500)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  S 327 1970

MONUMENTATION:           Bench Mark disk                       VM#:         6952
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AA0165
SETTING CLASSIFICATION:  Concrete base                         OPUS PID:        
LATITUDE:   24° 42.0' N (  24.70000)          LONGITUDE:  81° 30.3' W ( -81.50500)


The bench mark is a disk set on the top of the NW corner of a square concrete
base, 20.12 m (66.0 ft) north of and across the road from bench mark R 327 1970,
8.72 m (28.6 ft) south of bench mark T 327 1970, and 7.35 m (24.1 ft) south of
the SE corner of Building No. 954.



                         BENCH MARK STAMPING:  T 327 1970

MONUMENTATION:           Bench Mark disk                       VM#:         6953
AGENCY:                  National Geodetic Survey (NGS)        IDB PID#:  AA0163
SETTING CLASSIFICATION:  Concrete landing                      OPUS PID:        
LATITUDE:   24° 42.0' N (  24.70000)          LONGITUDE:  81° 30.3' W ( -81.50500)


The bench mark is a disk set on the top of the west end of the south landing of
Building No. 954, 5.64 m (18.5 ft) east of the SW corner of the building, 4.48 m
(14.7 ft) west of the SE corner of the building, 0.30 m (1.0 ft) east of the
west end of the landing, and 1 m (3 ft) above ground level.



                         BENCH MARK STAMPING:  4328 F 1982

MONUMENTATION:           Tidal Station disk                    VM#:         6954
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  AA0787
SETTING CLASSIFICATION:  Concrete platform                     OPUS PID:        
LATITUDE:   24° 42.0' N (  24.70000)          LONGITUDE:  81° 30.3' W ( -81.50500)


The bench mark is a disk set in the loading platform of the main building (No.
920) at the U.S. Air Force Radar Base, 16.40 m (53.8 ft) SW of the east corner
of the building, 15.91 m (52.2 ft) NE of the south corner of the building, 4.63
m (15.2 ft) NW of the east corner of the platform, 1.71 m (5.6 ft) west of the
steps leading to the building entrance, and 0.61 m (2.0 ft) above ground level.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  4

                                                                                
Station ID: 8724328                         PUBLICATION DATE:  09/22/2003
Name:       CUDJOE KEY NO. POINT                              
            FL
NOAA Chart: 11434                           Latitude:   24° 42.0' N (  24.70000)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.3' W ( -81.50500)


                                  D A T U M S 


Datums at CUDJOE KEY NO. POINT based on:

     LENGTH OF SERIES:      1 YEAR
     TIME PERIOD:           January 1971 - December 1971
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8724580 KEY WEST


Elevations of datums referred to Mean Lower Low Water (MLLW), in METERS:

     HIGHEST OBSERVED WATER LEVEL (12/16/1973)         =  1.205
     MEAN HIGHER HIGH WATER                     MHHW   =  0.819
     MEAN HIGH WATER                            MHW    =  0.748
     North American Vertical Datum              NAVD88 =  0.613
     MEAN TIDE LEVEL                            MTL    =  0.428
     MEAN SEA LEVEL                             MSL    =  0.409
     MEAN LOW WATER                             MLW    =  0.107
     MEAN LOWER LOW WATER                       MLLW   =  0.000
     LOWEST  OBSERVED WATER LEVEL (04/09/1972)         = -0.313

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     P 327 1970                                  1.479    0.731
     Q 327 1970                                  1.593    0.845
     S 327 1970                                  1.474    0.726
     T 327 1970                                  2.445    1.697
     4328 F 1982                                 2.552    1.804


Foot Notes:

Bench mark 4328 F 1982 is based on one differential leveling connection and does
not meet the quality control standards of the NOS. Therefore, caution should be
used when deriving elevations for this mark. 

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  4

                                                                                
Station ID: 8724328                         PUBLICATION DATE:  09/22/2003
Name:       CUDJOE KEY NO. POINT                              
            FL
NOAA Chart: 11434                           Latitude:   24° 42.0' N (  24.70000)
USGS Quad:  SUGARLOAF KEY                   Longitude:  81° 30.3' W ( -81.50500)


                             D E F I N I T I O N S


Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch.  It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).

NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint.  NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights.  Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at 
National Geodetic Survey.

NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded.  NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads.  NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929.  Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at 
National Geodetic Survey.

NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.

The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed. The NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.

The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum.  As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.

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Products available at 8724328 CUDJOE KEY NO. POINT, FL

Revised: 08/08/2018
NOAA / National Ocean Service
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