U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9457535 PUBLICATION DATE: 01/26/2015
Name: WEST RASPBERRY ISLAND
AK
NOAA Chart: 16576 Latitude: 58° 6.4' N ( 58.10717)
USGS Quad: AFOGNAK (A-5) ALASKA Longitude: 153° 20.4' W (-153.34011)
To reach the tidal bench marks from Port Lions, AK by boat, start at the
entrance to Settler Cove at position 57 52.428 N, 152 51.598 W, and proceed
in Kizhuyak Bay on course 043.6 T for 2.321 nautical miles (NM) to 57 54.213 N
152 46.435 W, then proceed through Whale Passage on course 310.3 T for
3.074NM to 57 56.201 N 152 50.851 W where Pokati Point will be abeam to
port. Continue through Kupreanof Strait on course 289.7 T for 14.533NM to 58
01.093 N 153 16.660 W with Outlet Cape abeam to port, then continue on course
279.6 T for 2.990NM until Malina Point is abeam to starboard at 58 01.593 N 153
22.226 W. Alter course to 312.3 T for 3.422NM until Raspberry Cape is abeam to
starboard at position 58 03.897 N 153 27.007 W and then proceed on course
036.1 T for 3.322NM to position 58 06.582 N 153 23.328 W. Finally, proceed
on course 104.1 T to enter Driver Bay where the benchmarks are located along
the rocky shore.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7535 A 2014
DESIGNATION: 945 7535 A
MONUMENTATION: Tidal Station disk VM#: 21304
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID#: BBDS43
LATITUDE: 58° 6.6' N ( 58.11000) LONGITUDE: 153° 20.3' W (-153.33861)
The primary bench mark is a disk set flush in bedrock, in a section of beach
with large loose rocks. It is 103.89 m (340.85 ft) NW of bench mark 7535 B 2014.
The lowest portion of the grassy bank, just before it curves W, is about 25 m
(82 ft) NW of the benchmark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9457535 PUBLICATION DATE: 01/26/2015
Name: WEST RASPBERRY ISLAND
AK
NOAA Chart: 16576 Latitude: 58° 6.4' N ( 58.10717)
USGS Quad: AFOGNAK (A-5) ALASKA Longitude: 153° 20.4' W (-153.34011)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7535 B 2014
DESIGNATION: 945 7535 B
MONUMENTATION: Tidal Station disk VM#: 21305
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 58° 6.6' N ( 58.10972) LONGITUDE: 153° 20.2' W (-153.33717)
The bench mark is a disk set flush in bedrock, extending from the cliffs behind
to a point. The beach in this area is sandy with small pebbles. It is 103.89 m
(340.85 ft) SE of bench mark 7535 A 2014, and 53.98 m (177.10) NNW from
benchmark 7535 C 2014.
BENCH MARK STAMPING: 7535 C 2014
DESIGNATION: 945 7535 C
MONUMENTATION: Tidal Station disk VM#: 21306
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 58° 6.6' N ( 58.10944) LONGITUDE: 153° 20.2' W (-153.33667)
The bench mark is a disk set flush in broken bedrock extending from the cliffs
behind. It is 53.98 m (177.10) SSE from benchmark 7535 B 2014 and 38.71 m
(127.00 ft) N of bench mark 7535 D 2014. One 950 feet charted peak on the SW
corner of Raspberry Island is visible when looking E.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9457535 PUBLICATION DATE: 01/26/2015
Name: WEST RASPBERRY ISLAND
AK
NOAA Chart: 16576 Latitude: 58° 6.4' N ( 58.10717)
USGS Quad: AFOGNAK (A-5) ALASKA Longitude: 153° 20.4' W (-153.34011)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7535 D 2014
DESIGNATION: 945 7535 D
MONUMENTATION: Tidal Station disk VM#: 21307
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 58° 6.5' N ( 58.10889) LONGITUDE: 153° 20.2' W (-153.33667)
The bench mark is a disk set flush in a low horizontal bedrock outcrop,
approximately 3m from the cliff face behind. It is 38.71 m (127.00 ft) S of
bench mark 7535 C 2014 and 38.37 m (125.89 ft) NNE from bench mark 7535 E 2014,
and due E from the primary benchmark.
BENCH MARK STAMPING: 7535 E 2014
DESIGNATION: 945 7535 E
MONUMENTATION: Tidal Station disk VM#: 21308
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Bedrock outcrop OPUS PID:
LATITUDE: 58° 6.5' N ( 58.10861) LONGITUDE: 153° 20.2' W (-153.33694)
The bench mark is a disk set flush in a bedrock outcrop extending from cliff
behind. It is 38.37 m (125.89 ft) SSW from bench mark 7535 D 2014. Two peaks
charted as 1404 and 950 feet on Raspberry Island bear 115 T (098 M) and 123 T
(105 M) from the benchmark.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9457535 PUBLICATION DATE: 01/26/2015
Name: WEST RASPBERRY ISLAND
AK
NOAA Chart: 16576 Latitude: 58° 6.4' N ( 58.10717)
USGS Quad: AFOGNAK (A-5) ALASKA Longitude: 153° 20.4' W (-153.34011)
T I D A L D A T U M S
Tidal datums at WEST RASPBERRY ISLAND based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: May 2014 - June 2014
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9457804 ALITAK, LAZY BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 4.279
MEAN HIGH WATER MHW = 4.021
MEAN TIDE LEVEL MTL = 2.261
MEAN SEA LEVEL MSL = 2.241
MEAN LOW WATER MLW = 0.500
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7535 A 2014 4.867 0.846
7535 B 2014 4.217 0.196
7535 C 2014 6.187 2.166
7535 D 2014 6.026 2.005
7535 E 2014 4.904 0.883
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9457535 PUBLICATION DATE: 01/26/2015
Name: WEST RASPBERRY ISLAND
AK
NOAA Chart: 16576 Latitude: 58° 6.4' N ( 58.10717)
USGS Quad: AFOGNAK (A-5) ALASKA Longitude: 153° 20.4' W (-153.34011)
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.