U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9412802 PUBLICATION DATE: 09/19/2013
Name: MANSFIELD CONE, PACIFIC OCEAN
CA
NOAA Chart: 18700 Latitude: 35° 57.0' N ( 35.94953)
USGS Quad: CAPE SAN MARTIN Longitude: 121° 28.9' W (-121.48194)
From the intersection of Vista del Mar Avenue and Highway 1 on the east side of
San Simeon, proceed 53.9 km (33.5 mi) NW on Highway 1 to the Sand Dollar Beach
recreation area, continue 3.4 km (2.1 mi) NW on Highway 1 to a gravel pulloff on
the west side of the highway. Park and continue on foot over a stile over the
barbed wire fence and along a dirt trail 0.45 km (0.28 mi) west to the base of
Mansfield Cone, climb down the rock scree bluff to a rock ledge at the water
line. The bench marks are along the trail leading to Mansfield Cone and on the
rock outcrops down near the water on the south side of Mansfield Cone. The tide
gauges were located on top of the rock bluff directly below Mansfield Cone and
the orifices were attached to a rock outcrop directly below.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2802 A 2012
DESIGNATION: 941 2802 A
MONUMENTATION: Bench Mark disk VM#: 20687
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop or ledge. OPUS PID:
LATITUDE: 35° 57.0' N ( 35.94953) LONGITUDE: 121° 29.0' W (-121.48250)
The primary bench mark is a disk set in a rock ledge below Mansfield Cone, 7.29
m (23.9 ft) N of the southern point of the rock outcrop, 3.80 m (12.5 ft) S of a
sheer rock face below Mansfield Cone, 0.53 m (1.7 ft) WNW of the edge of the
ledge and about 4.97 m (16.3 ft) below the top of the rock outcrop.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9412802 PUBLICATION DATE: 09/19/2013
Name: MANSFIELD CONE, PACIFIC OCEAN
CA
NOAA Chart: 18700 Latitude: 35° 57.0' N ( 35.94953)
USGS Quad: CAPE SAN MARTIN Longitude: 121° 28.9' W (-121.48194)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2802 B 2012
DESIGNATION: 941 2802 B
MONUMENTATION: Bench Mark disk VM#: 20688
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop or ledge. OPUS PID:
LATITUDE: 35° 57.0' N ( 35.94950) LONGITUDE: 121° 28.9' W (-121.48192)
The bench mark is a disk set in a rock outcrop, 27.97 m (91.8 ft) SW of rock
bluff on shore at E end of rock outcrop, 15.40 m (50.5 ft) SW of highest point
on rock outcrop with sparse vegetation, 13.42 m (44.0 ft) NE of western most
extent of rock outcrop and 1.51 m (5.0 ft) NW of nearest rock high point.
BENCH MARK STAMPING: 2802 C 2012
DESIGNATION: 941 2802 C
MONUMENTATION: Bench Mark disk VM#: 20689
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop or ledge. OPUS PID:
LATITUDE: 35° 57.0' N ( 35.94967) LONGITUDE: 121° 28.9' W (-121.48156)
The bench mark is a disk set in a white outcrop at the head of a small
cove,26.13 m (85.7 ft) E of the grassy high point on the long rock outcrop that
extends into the ocean, 12.67 m (41.6 ft) E of the E end of the long rock
outcrop that extends SW into the ocean, 11.35 m (37.2 ft) WSW slope distance of
the top of the dirt bluff and 6.36 m (20.9 ft) ESE of a narrow dirt trail
through the low brush to the top of the bluff.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9412802 PUBLICATION DATE: 09/19/2013
Name: MANSFIELD CONE, PACIFIC OCEAN
CA
NOAA Chart: 18700 Latitude: 35° 57.0' N ( 35.94953)
USGS Quad: CAPE SAN MARTIN Longitude: 121° 28.9' W (-121.48194)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Mon-01 pm 16.1 NGS Mansfield Cone
2 GPS-15 1986
DESIGNATION: Mansfield Cone 2 GPS 15
MONUMENTATION: Bench Mark disk VM#: 20690
AGENCY: California Department of TransportationIDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop or ledge. OPUS PID#: BBCX12
LATITUDE: 35° 57.0' N ( 35.94983) LONGITUDE: 121° 28.9' W (-121.48216)
The bench mark is a disk set in a rock depression near the top of the outcrop,
32.50 m (106.6 ft) ENE of the base of Mansfield Cone, 17.15 m (56.3 ft) on a
slope W of the trail from the road, 10.55 m (34.6 ft) NW of the S edge of the
rock outcrop which is a cliff above the ocean and 2.23 m (7.3 ft) S of the
highest point of the rock outcrop.
BENCH MARK STAMPING: 2802 D 2012
DESIGNATION: 941 2802 D
MONUMENTATION: Bench Mark disk VM#: 20691
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop or ledge. OPUS PID:
LATITUDE: 35° 57.0' N ( 35.95058) LONGITUDE: 121° 28.8' W (-121.48011)
The bench mark is a disk set in a rock in the brush, 47.70 m (156.5 ft) S of the
S end of a guardrail on the west side of Highway 1, 20.40 m (66.9 ft) NW of a
small stream in a gully, 4.33 m (14.2 ft) NE of the centerline of the dirt trail
and about 1.20 m (3.9 ft) higher than the trail.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9412802 PUBLICATION DATE: 09/19/2013
Name: MANSFIELD CONE, PACIFIC OCEAN
CA
NOAA Chart: 18700 Latitude: 35° 57.0' N ( 35.94953)
USGS Quad: CAPE SAN MARTIN Longitude: 121° 28.9' W (-121.48194)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: H 1316 1977
DESIGNATION: H 1316
MONUMENTATION: Flange-encased Rod VM#: 20833
AGENCY: NGS IDB PID#: FV1151
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 35° 56.8' N ( 35.94597) LONGITUDE: 121° 28.6' W (-121.47611)
The bench mark is a disk on a rod inside of a white pvc pipe with pvc cap, 60.20
m (197.5 ft) NW of a white marker on the S side of a culvert on the E side of
highway 1, 45.25 m (148.5 ft) N of the entrance to the driveway, 6.00 m (19.7
ft) E of the centerline of the driveway, 3.45 m (11.3 ft) S of a fence post and
about 0.05 m (0.2 ft) lower than the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9412802 PUBLICATION DATE: 09/19/2013
Name: MANSFIELD CONE, PACIFIC OCEAN
CA
NOAA Chart: 18700 Latitude: 35° 57.0' N ( 35.94953)
USGS Quad: CAPE SAN MARTIN Longitude: 121° 28.9' W (-121.48194)
T I D A L D A T U M S
Tidal datums at MANSFIELD CONE, PACIFIC OCEAN based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: April 2013 - June 2013
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9412110 PORT SAN LUIS, SAN LUIS OBISPO BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.597
MEAN HIGH WATER MHW = 1.381
MEAN TIDE LEVEL MTL = 0.847
MEAN SEA LEVEL MSL = 0.835
MEAN LOW WATER MLW = 0.314
North American Vertical Datum NAVD88 = 0.000
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2802 A 2012 2.274 0.893
2802 B 2012 4.645 3.264
2802 C 2012 9.937 8.556
Mon-01 pm 16.1 NGS Mansfield Cone 2
GPS-15 1986 22.725 21.344
2802 D 2012 41.248 39.867
H 1316 1977 44.176 42.795
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9412802 PUBLICATION DATE: 09/19/2013
Name: MANSFIELD CONE, PACIFIC OCEAN
CA
NOAA Chart: 18700 Latitude: 35° 57.0' N ( 35.94953)
USGS Quad: CAPE SAN MARTIN Longitude: 121° 28.9' W (-121.48194)
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.