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Roadmap to the new Datums of 2022

Roadmap to the new Datums of 2022

 

Quarter 1, 2018 Article

By: Brian Fisher

 

Several things are going on at the National Geodetic Survey (NGS), most notably the current datums: North American Datum of 1983 (NAD83) and North
American Vertical Datum of 1988 (NAVD88) are scheduled to be replaced with new datums, North American Terrestrial Reference Frame of 2022 (NATRF2022) and North American-Pacific Geopotential Datum of 2022 (NAPGD2022).  This article will outline several of the steps to get to the new reference frame and vertical datum and how we at the local level in Arizona can be involved to influence the products we receive
back from NGS. 

The mission of NGS is to define, maintain, and provide access to the National Spatial Reference System (NSRS). The NSRS provides a consistent coordinate system that defines latitude, longitude, height, scale, gravity, and orientation throughout the United States and its territories.  The NGS home page, https://geodesy.noaa.gov/ gives the public access to data, tools, data processing portals (OPUS), and contact information for NGS staff. 

According to the current schedule, the new datums are scheduled for release about four years from now.  The changes caused by this can be categorized
into the activities that will happen before the new datums are released, and
changes caused when the new datums come out. 
Lead up activities will include: two important staff positions for
communication with NGS, the Regional Geodetic Advisor and the State Geodetic
Coordinator; the final geoid model used with the current vertical datum (GEOID18);
redefinition of the State Plane Coordinate (SPC) system (low distortion projection
‘LDP’ design methods will be an option); reinvention of the interface between
NGS and how people will submit data to them (OPUS-Share, OP2IDB, DSWorld).  Things that will occur with the release of
the new datum will include: an entirely new vertical datum (NAPGD2022); updated
coordinates for all modern survey control marks (NATRF2022) including CORS,
OPUS-Share and passive marks with post 1997 GPS observations; new
transformation tools to facilitate working with legacy data (NCAT).

Who will this effect in Arizona?  Short answer is all of us, but some more than
others.  Agencies, typically federal,
governed by OMB Circular A-16 will be mandated to produce their new spatial
data products in the new datums when they are released by NGS.  Users of this data will also be effected
because the data they receive from these agencies will be on the new systems.  Any user of NGS products will be transitioned
to use the new datums also.  This will
include the position published on data sheets and the position computed when
using OPUS (RS, Static, Share, Projects, etc.). 
Users of CORS will also be effected as the CORS will be positioned in
the new reference system.

How big is the change?  NATRF2022
will differ from NAD83 by about five feet in Arizona.  Most of this is in the horizontal but there
will be about two and a half feet in the ellipsoid height.  This differs greatly from the NAD83 adjustments
we have seen in the last three decades.  Previous
NAD83 adjustments have been at the sub-foot level, in numerical difference
(e.g. NAD83(92) or HARN, NAD83(CORS96/2007), NAD83(2011:2010), and for many
users this sub-foot difference is nearly invisible. The 2022 reference system redefinition
will be huge in comparison and most all of the professional level data users
will need to take notice.

How can we as a State get ready for the new datums?  There are several ways to both be involved
and to prepare.  NGS will be producing
products with the data they have, irrespective of what we do on a local level. If
NGS has a small amount of data in a region, the quality of the products in that
region will not be as good as in regions with more data.  NGS is distributing lists of survey marks
that data is being requested for to improve the products NGS is working on
preparing.  First up is a GPS on Benchmark
campaign going on now and ending in August 2018.

NGS is giving us as a State the opportunity to contribute
data and designs back to them so that NGS can help us.  The relationship between NGS and the States
is very similar to the relationship between a manager, supervisor and the
worker.  The manager and supervisor
typically do not perform ‘the work’, they just make sure the worker has
everything they need to get ‘the work’ done. 
In this analogy, NGS is the manager of geodetic data.  The supervisor is much like the position of
an NGS Regional Advisor and State Coordinator, where the workers are the rest
of us, a mixture of Federal, State, County, City and private surveyors.  ‘The work’ is listed in the next paragraph.

Field observations can be made and submitted to improve both
GEOID18 and NCAT transformation tools. 
Work groups of stakeholders can meet at the state level and directly
influence the SPC coordinate systems being designed for 2022.  Later this year articles about these projects
will be published and your involvement will be requested. 

The Regional Geodetic Advisor is a federal employee of
NOAA’s National Geodetic Survey. The Advisor serves as a liaison between NGS
and its public, academic, and private sector constituents within their assigned
region. They provide expert guidance and assistance to these constituents who
are managing the geodetic component of geospatial activities that are tied to
the NSRS. Geodetic advisors serve as subject matter experts in geodesy and
regional geodetic issues, collaborating internally across NGS and NOAA to
further the organizations’ missions. They are to maintain awareness of current
developments in geodetic science and technology, updates and improvements to
geodetic reference systems, and application to geospatial activities.
Recognizing that a Regional Advisor supports an entire region in which individual
states may have local and unique geodetic needs or priorities, NGS recommends
that each state identify someone to serve as a State Geodetic Coordinator.

The State Geodetic Coordinator is not employed by NGS and is
assigned by a state government agency or university. The Coordinator serves as
a liaison between the state and NGS. State Coordinators should have technical
expertise in geodesy to make informed decisions about and provide guidance for
geospatial activities that benefit from connecting to the NSRS. The State
Geodetic Coordinator is a primary point of contact in the state for the
Regional Geodetic Advisor.

Arizona is located within the tristate Southwest Region of Arizona,
New Mexico, and Utah.  The NGS Southwest
Regional Advisor is Bill
Stone
, and the Arizona State Geodetic Coordinator is Brian
Fisher
.  

Important websites to bookmark are the NGS
home page
, and the Advisors page.  Contact information for your advisor and
coordinator are located there.

Both the advisor and coordinator are here to help the public
with training opportunities and to assist surveyors in the submission of data
to the NSRS databases.  There are many
ways for the Arizona survey and geospatial community to get involved. For more
information in Arizona contact:

Brian S. Fisher, RLS

State Geodetic Coordinator, AZ

c\o Central Arizona Project

23636 N. Seventh Street

Phoenix, AZ 85024

phone: (602) 403-7932

email: GeodesyArizona@gmail.com

 

 

Arizona Geographic Information Council © 2012. All rights reserved.