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Bench Mark Sheet for 8448558, Edgartown MA

Superseded Epoch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Small blue map location marker Unpublished bench mark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: 8448558                         PUBLICATION DATE:  06/12/2009
Name:       EDGARTOWN, MARTHA'S VINEYARD                      
            MA
NOAA Chart: 13233                           Latitude:   41° 23.3' N (  41.38830)
USGS Quad:  EDGARTOWN                       Longitude:  70° 30.7' W ( -70.51170)


From Woods Hole, take the ferry to Oaks Bluff on Martha's Vineyard, then take
Seaview Avenue south, then Beach Road south, then Edgartown Oaks Bluff Road
south to Edgartown. The bench marks are downtown, in the vicinity of the ferry
to Chappaquiddick Island. The tide gauge was located on the Edgartown Memorial
Pier.


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


                 PRIMARY BENCH MARK STAMPING:  NO 9 1960
                         DESIGNATION:          844 8558 TIDAL 9

MONUMENTATION:           Bench Mark disk                       VM#:        17666
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete seawall                      OPUS PID#: BBBJ75
LATITUDE:   41° 23.3' N (  41.38830)          LONGITUDE:  70° 30.7' W ( -70.51170)


The bench mark is a disk set in an old concete seawall adjacent to the public
piers, 31 m (102 ft) south of the center of the Dock Street, 23 m (75 ft) west
of a yard arm shaped flagpole located in front of the JYC yacht club building,
and 0.3 m (1.0 ft) from the junction of a brick walkway and wooden quay. 

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

                                                                                
Station ID: 8448558                         PUBLICATION DATE:  06/12/2009
Name:       EDGARTOWN, MARTHA'S VINEYARD                      
            MA
NOAA Chart: 13233                           Latitude:   41° 23.3' N (  41.38830)
USGS Quad:  EDGARTOWN                       Longitude:  70° 30.7' W ( -70.51170)


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


                         BENCH MARK STAMPING:  NO 6 1928
                         DESIGNATION:          844 8558 TIDAL 6

MONUMENTATION:           Bench Mark disk                       VM#:        17667
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID#:       
LATITUDE:   41° 23.3' N (  41.38830)          LONGITUDE:  70° 30.7' W ( -70.51170)


The bench mark is a disk set vertically in the concrete foundation of the
Edgartown National Bank located on Martha's Vineyard, 4.2 m (13.8 ft) north from
the center of Main Street, 2.8 m (9.2 ft) west of the center of Water Street,
0.5 m (1.6 ft) west of the SE corner of the building, and 0.3 m (1.0 ft) from
the base of the building. 



                         BENCH MARK STAMPING:  NO 11 1961
                         DESIGNATION:          844 8558 TIDAL 11

MONUMENTATION:           Bench Mark disk                       VM#:        17668
AGENCY:                  US Coast and Geodetic Survey
                         (USC&GS)                              IDB PID#:        
SETTING CLASSIFICATION:  Curb                                  OPUS PID#: BBDN12
LATITUDE:   41° 23.4' N (  41.39000)          LONGITUDE:  70° 30.7' W ( -70.51170)


The bench mark is a disk set in a roadside curb on the SE corner of the
intersection of Mayhew Lane and Dock Street, 30 m (98.4 ft) north of bench mark
NO 9 1960, 24 m (78.7 ft) SE of a red and white fire hydrant located at the NW
corner of Mayhew Lane and Dock Street, 10 m (32.8 ft) SE of the intersection of
Mayhew Lane and Dock Street, and 0.75 m (2.5 ft) west of a powerline pole. 

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

                                                                                
Station ID: 8448558                         PUBLICATION DATE:  06/12/2009
Name:       EDGARTOWN, MARTHA'S VINEYARD                      
            MA
NOAA Chart: 13233                           Latitude:   41° 23.3' N (  41.38830)
USGS Quad:  EDGARTOWN                       Longitude:  70° 30.7' W ( -70.51170)


                            T I D A L   D A T U M S 


Tidal datums at EDGARTOWN, MARTHA'S VINEYARD based on:

     LENGTH OF SERIES:      31 Days
     TIME PERIOD:           August 6, 2004 - September 6, 2004
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  8449130 NANTUCKET ISLAND, NANTUCKET SOUND


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

     MEAN HIGHER HIGH WATER                     MHHW   =  0.816
     MEAN HIGH WATER                            MHW    =  0.719
     MEAN SEA LEVEL                             MSL    =  0.435
     MEAN TIDE LEVEL                            MTL    =  0.394
     MEAN LOW WATER                             MLW    =  0.069
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 9 1960                                   1.098    0.379
     NO 6 1928                                   3.708    2.989
     NO 11 1961                                  1.436    0.716


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

                                                                                
Station ID: 8448558                         PUBLICATION DATE:  06/12/2009
Name:       EDGARTOWN, MARTHA'S VINEYARD                      
            MA
NOAA Chart: 13233                           Latitude:   41° 23.3' N (  41.38830)
USGS Quad:  EDGARTOWN                       Longitude:  70° 30.7' W ( -70.51170)


                             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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Revised: 08/08/2018
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