SECTIONS 8890-8902 - California Statutes

PUBLIC RESOURCES CODE

SECTION 8890-8902

8890. Orthometric heights within the State of California that are
based on the North America Vertical Datum of 1988 and conforming to
the provisions of this chapter shall be known as "California
Orthometric Heights of 1988." Orthometric heights are commonly
referred to as "elevations."

8891. As used in this chapter:
(a) "NGS" means National Geodetic Survey or its successor.
(b) "CSRC" means California Spatial Reference Center or its
successor.
(c) "NAVD88" means North American Vertical Datum of 1988.
(d) "GPS" means Global Positioning System and includes other,
similar space-based systems.
(e) "FGDC" means the Federal Geographic Data Committee or its
successor.
(f) "FGCS" means the Federal Geodetic Control Subcommittee or its
successor.
(g) "CSRN" means California Spatial Reference Network as defined
by Chapter 3 (commencing with Section 8850), "Geodetic Datums and the
California Spatial Reference Network."
(h) "COH88" means California Orthometric Heights of 1988.

8892. The phrase "California Orthometric Heights of 1988" or any
abbreviation, such as "COH88," thereof shall be used only in
reference to orthometric heights based on NAVD88 and conforming to
the provisions of this chapter.

8893. COH88 values shall be expressed in meters and decimals of a
meter or in feet and decimals of a foot. When COH88 values are
expressed in feet, the "U.S. Survey Foot," (one foot equals 1200/3937
meters) shall be used as the standard foot.

8894. COH88 values that are determined from differential leveling
surveys shall be known as "leveled COH88" values. COH88 values that
are determined from GPS surveys and the appropriate application of a
geoid model shall be known as "derived COH88" values.

8895. When a geoid model is used to determine derived COH88 values,
it shall be the latest geoid model published by NGS.

8896. The accuracy of derived COH88 values may be improved by
applying a "local orthometric height correction" to the geoid height
determined from the latest, applicable geoid model published by NGS.

8897. The survey that establishes a COH88 value or values shall
meet all of the following requirements:
(a) The survey shall be referenced to and shall have
field-observed statistically independent connections to one or more
orthometric height reference stations that is or are one of the
following:
(1) CSRN station.
(2) Geodetic control station located outside of the State of
California that meets all the requirements for inclusion in the CSRN
except that the station is outside California.
(3) Existing COH88 station that (A) is shown on a map filed with
the applicable county surveyor by a public officer, subdivision map,
corner record, or record of survey, (B) meets all the requirements
for inclusion in the CSRN, except that the station and its data are
not published by NGS or CSRC, and (C) has an accuracy, conforming to
the applicable CSRN requirements, stated for the station's value.
(4) Existing COH88 station that is shown on a public map or
document that (A) is compiled and maintained by the applicable county
surveyor, (B) meets all the requirements for inclusion in the CSRN
except that the station and its data are not published by NGS or
CSRC, and (C) has an accuracy, conforming to the applicable CSRN
requirements, stated for the station's value.
(b) If an accuracy is to be claimed for the COH88 value or values
established, the claimed accuracy shall be an accuracy standard
published by FGDC or FGCS.

8898. If an accuracy is claimed for a COH88 value or values, the
survey that established the value or values shall be documented on a
map, record of survey, corner record, or other document that
includes, at a minimum, the following:
(a) For each COH88 station, the resultant COH88 value.
(b) For each individual COH88 value, whether it is a leveled COH88
or a derived COH88 value.
(c) For leveled COH88 values, the beginning and ending dates of
the observations used to determine the values.
(d) For derived COH88 values, the date of the NGS geoid model used
to determine the values.
(e) When derived COH88 values are shown and reflect the
application of a "local orthometric height correction model," written
data that justifies the model's validity. Such written data shall
include a summary of the procedures, computations, analysis, and
validation process used to develop the model.
(f) For derived COH88 values, the epoch (date), in a decimal year
format to two decimal places, that is the basis of the COH88 values
shown. Said epoch shall be the published NGS or CSRC epoch of a
controlling station for the survey.
(g) The FGDC or FGCS accuracy standard of the COH88 value or
values established. FGDC accuracies shall be identified as either a
local or network accuracy.
(h) Additional written data that justifies the FGDC or FGCS
accuracy standard shown. Such additional written data shall include
observation equipment, control diagram including required
field-observed statistically independent connection or connections,
adjustment methodology and software used, a summary of the procedures
used or a reference to a published commonly accepted procedural
specifications, final residuals or closures, and other data essential
for others to evaluate the survey.

8899. When a COH88 value or values are shown on any document, the
document shall include the following:
(a) A statement that the orthometric height or heights shown are a
COH88 value or values; exceptions shall be noted.
(b) The station or stations to which the COH88 value or values are
referenced and connected and the orthometric height value or values
and the published or stated accuracy or accuracies of said referenced
station or stations.

8900. The use of COH88 by any person, firm, or governmental agency
is optional.

8901. This chapter does not impair or invalidate land titles, legal
descriptions, or jurisdictional or land boundaries and, further,
this chapter does not impair or invalidate references to, or the use
of, datums, elevations, orthometric heights, or other height values
that do not conform to this chapter except as specified in Section
8892 in this chapter.

8902. This chapter does not prohibit the use of new surveying
technologies or techniques for which FGCS specifications or other
accepted specifications have not yet been published.