GO-ITS 542TES National Transformation Tools

Overview

The National Transformation version 2 or NTv2 is to be used to transform horizontal data between the North America Datum 1927 (NAD27) and the North America Datum 1983 (NAD83), or between NAD83-Original version (NAD83-ORIG) and NAD83-Canadian Spatial Reference System (NAD83-CSRS). The Conversion Grid from the difference between the Height Transformation version 2.0 (HT2.0) and the Canadian Gravimetric Geoid model of 2013 – version A (CGG2013a) allows for the transformation of vertical data between the Canadian Geodetic Vertical Datum 1928 (CGVD28) and the Canadian Geodetic Vertical Datum 2013 (CGVD2013).  The Height Transformation version 2.0 (HT2.0) Tool methodology is used to transform ellipsoidal heights to orthometric heights that are related to the vertical datum Canadian Geodetic Vertical Datum 1928 (CGVD28), and the supporting GPS-H utility allows for the conversion of GPS derived ellipsoidal heights to orthometric heights related to the Canadian Geodetic Vertical Datum 2013 (CGVD2013).

1. Introduction

Government of Ontario Information Technology (GO-IT) Standards are the official publications on the IT standards adopted through the Office of the Corporate Chief Information Officer (OCCIO) and IT Executive Leadership Council (ITELC) for use across the government’s information and information technology (I&IT) infrastructure.

These publications support the responsibilities of the Treasury Board Secretariat for coordinating standardization of I&IT in the Government of Ontario. In particular, GO-IT Standards describe where the application of an IT standard is mandatory and specify any qualifications governing the implementation of the IT standards. 

2. Summary

2.1 Standard Name and Description

GO-ITS 542TES - National Transformation Tools (formerly GO-ITS 45.2) defines the official geodetic transformation tools for Ontario. As such, this document defines the National Transformation Tools which include:

• The National Transformation version 2 (NTv2) methodology that is used primarily to transform geospatial information between the North America Datum 1927 (NAD27) and the North America Datum 1983 (NAD83). The NTv2 can also be used to transform between NAD83-ORIG and NAD83-CSRS.
• The TRX coordinate transformation tool that is used to transform between various versions/epochs of NAD83-CSRS using the predicted velocities from the Canadian Velocity Grid.
• The Conversion Grid from the difference between the Height Transformation version 2.0 (HTv2.0) related to the Canadian Geodetic Vertical Datum 1928 (CGVD28) and the Canadian Gravimetric Geoid Model of 2013 – version A (CGG2013a) associated with the Canadian Geodetic Vertical Datum 2013 (CGVD2013).
• The Height Transformation version 2.0 (HT2.0) Tool methodology that is used to transform ellipsoidal heights to orthometric heights that are related to the vertical datum Canadian Geodetic Vertical Datum 1928 (CGVD28).
• The GPS·H Tool methodology that is used to transform GNSS ellipsoidal heights that are related to NAD83-CSRS to orthometric heights that are related to the new vertical datum Canadian Geodetic Vertical Datum 2013 (CGVD2013).

This standard is not specific to a single ministry or agency. 

2.2 Background and rationale

This revised GO-IT Standard is established to implement updates to the former GO-IT Standard 45.2 document. With the implementation of the related GO-ITS 544TES Vertical Datum Standard beginning in 2024 (which additionally provides a new standard vertical geodetic datum), there is a need for supporting tools and methodologies that will allow for transformation between the old de facto vertical datum Canadian Geodetic Vertical Datum 1928 (CGVD28) and the new vertical datum Canadian Geodetic Vertical Datum 2013 (CGVD2013). Currently GO-IT Standard 45.2 provides for the National Transformation Version 2 (NTv2) methodology to be used when converting between North American Datum 1927 (NAD27) and North American Datum 1983 (NAD83) horizontal datums. The implementation of this revised standard (i.e., GO-ITS 542TES) additionally provides height transformation tools (Conversion Grid, HT2.0 and GPS·H) for converting between vertical datums CVGD28 and CVGD2013. The details regarding NTv2 remain the same.  National Transformation Tools should be obtained from the Canadian Geodetic Survey – Natural Resources Canada (CGS – NRCan) or be directly included in GIS systems or other transformation software. Updates, additional information and supporting files specifically for Ontario will be available through the Ontario GeoHub or possibly the Geodesy Ontario website.

The expected benefits and results of GO-ITS 542TES National Transformation Tools are to:

• provide a provincial standard for three-dimensional transformation of geospatial information
• enhance awareness that geospatial information is referenced to a horizontal and vertical geodetic datum,
• enhance awareness that geospatial information is not directly compatible unless the data is consistently referenced to one horizontal geodetic datum and/or one vertical geodetic datum, and
• help ensure the integrity of geospatial information while promoting the sharing and exchange of data across ministries, agencies, and between the public and private sectors

2.3 Target audience

The target audience for this document includes, but is not limited to: 

• All Ontario ministries/clusters Conservation Authorities
• Association of Ontario Land Surveyors (AOLS)
• Ontario Municipalities
• GIS and GNSS/GPS service providers and users
• Professional Surveyors and Engineers in Ontario, and
• the Geomatics Community of Ontario.

2.4 Scope

2.4.1 In scope

The scope of this document is to provide a provincial standard for:

• the horizontal transformation of geospatial information between NAD27 and NAD83, NAD83-Original and NAD83-CSRS, and
• the methodologies to be used when transforming/converting between CGVD28 and CGVD2013 vertical datums, as well as to transform GNSS ellipsoidal heights to GNSS-based orthometric heights related to the new vertical datum CGVD2013.

2.4.2 Out of scope

The out of scope of this document is to require:

• the transformation of geospatial data.
• the use of CGVD2013 (GO-IT Standard 544TES, formerly GO-ITS 45.4).

2.5 Applicability statements

2.5.1 Organization

All Ministries and I&IT Clusters are subject to Government of Ontario IT Standards.

All adjudicative and advisory agencies are subject to Government of Ontario IT Standards.

All other agencies that are using OPS information and information technology products or services are required to comply with Government of Ontario IT standards if they are subject to either the Governance and Management of Information Technology Directive or Government of Ontario IT Standards by memorandum of understanding.

As new GO-IT Standards are approved, they are deemed mandatory on a go-forward basis (go-forward basis means at the next available project development or procurement opportunity).

When implementing or adopting any Government of Ontario IT standards or IT standards updates, Ministries, I&IT Clusters and applicable agencies must follow their organization’s pre-approved policies and practices for ensuring that adequate change control, change management, and risk mitigation mechanisms are in place and employed. For the purposes of this document, any reference to Ministries or the Government includes applicable agencies.

2.5.2 Other applicability

Municipalities, local or regional governments or agencies do not need to comply with this standard individually, unless they submit data to OPS ministries or enter into a joint/cooperative projects or initiatives with one or more OPS ministries.

Land Information Ontario (LIO) is a provincial initiative that supports the province-wide sharing of geographic data. LIO provides centralized access to data through a number of tools and services, including the LIO Warehouse, the Ontario Geospatial Data Exchange, the Ontario Land Information Directory, and LIO Internet Mapping.

LIO uses, supports, and maintains georeferencing standards and tools to ensure that public sector organizations are consistently referencing their geographic data holdings to a single modern referencing system that is GPS compatible and used by most GIS users.

2.5.3 Requirement levels

Within this document, certain wording conventions are followed. There are precise requirements and obligations associated with the following terms:

Must - This word, or the terms "required" or "shall", means that the statement is an absolute requirement.

Should - This word, or the adjective "recommended", means that there may exist valid reasons in particular circumstances to ignore the recommendation, but the full implications (for example, business functionality, security, cost) must be understood and carefully weighed before choosing a different course. 

3. Technical specification

The following requirements apply to all I&IT assets and operations within the scope of the Governance and Management of Information Technology Directive. 

3.1 Mandatory

GO-IT Standard 542TES - National Transformation Tools - Only this standard shall be used when transforming horizontal geospatial information between the NAD27 datum and the NAD83 datum or between NAD83 realizations (NAD83-ORIG and NAD83-CSRS), or when transforming vertical geospatial information between CGVD28 and CGVD2013.  Geospatial information includes horizontal and/or vertical or 3D point coordinate information, digital mapping information and GIS information. It is not the purpose of this standard to require transformation of geospatial information, but to provide the methodology when transformation between horizontal and/or vertical datums is required.

This standard is not specific to a single ministry or agency.

3.2 Non-mandatory

The immediate transformation of horizontal and/or vertical data sets (including GIS data/layers) is not required. However, any horizontal and/or vertical data sets (including GIS data/layers) that must be transformed to newer horizontal and/or vertical datums shall use the methodologies and tools detailed in this standard. (See GO-IT Standard 541TES and the proposed GO-IT Standard 544TES for newer datums required within Ontario.) 

4. Related standards and impacted infrastructure

4.1 Impacts to existing standards

Identify any standards that reference or are referenced by this standard and describe the impact.

4.2 Impacts to existing infrastructure

Identify any applications, systems, solutions and technology platforms that could be affected by this standard and describe the impact.

5. Compliance requirements

In order to manage the effectiveness and implementation of this standard, Ministries, I&IT Clusters and applicable agencies are expected to adopt and monitor compliance. 

6. Roles and responsibilities

Accountable Role (Standard Owner) Definition

The individual or committee ultimately accountable for the effectiveness of a standard and for its full life-cycle, including development, reviews, revisions, updates, evaluations, and rescindment. Where a committee owns the standard, the committee Chair is accountable for the standard. There must be exactly one accountable role identified. 

Accountable Role:

Name: Larissa Mathewson-Brake
Title: Director, Mapping & Information Resources Branch
Ministry/I&IT Cluster: Ministry of Natural Resources and Forestry/ Land and Resources I+IT Cluster
Division: Corporate Management and Information Division 

Responsible Role Definition

The organization(s) responsible for the development of this standard. There may be more than one responsible organization identified if it is a partnership/joint effort. (Note: the responsible organization(s) provides the resource(s) to develop the standard). 

Responsible Organization(s):

Ministry/I&IT Cluster: Ministry of Natural Resources and Forestry/ Land and Resources I+IT Cluster
Division: Corporate Management and Information Division
Branch: Mapping and Information Resources Branch 

Support Role Definition

The support role is the resource(s) to whom the responsibility for maintaining this standard has been assigned. Inquiries, feedback, and suggestions should be sent to this resource. 

Support Role (Editor):

Ministry/I&IT Cluster: Ministry of Natural Resources and Forestry/ Land and Resources I+IT Cluster
Division: Corporate Management and Information Division
Branch: Mapping and Information Resources Branch
Section: Office of the Surveyor General
Job Title: Provincial Geodesist
Name: Morgan Goadsby
Phone: 705-313-2789
Email: morgan.goadsby@ontario.ca 

2^nd Support Role

Section: Office of the Surveyor General
Job Title: Geodetic Control Survey Specialist
 Name: Hassan Ibrahim
 Phone: 437-881-3190
 Email: hassan.ibrahim@ontario.ca

7. Consultations

Areas consulted as part of the development of this standard. Include individuals and committees, councils and/or working groups:

8. Document history

9. Glossary

GPS -

Global Positioning System (USA).

GNSS -

Global Navigation Satellite Systems – (including GPS, GLONASS, Galileo, etc.).

GeoDMC -

OPS Geomatics Directors-Managers Committee.

GeoTASC -

OPS Geomatics Technical Advisory Sub-Committee of GeoDMC.

Geoid -

An equipotential surface representing Mean Sea Level below the Earth’s surface.

Reference Ellipsoid -

An ellipsoid (3-D shape) used to represent the size and shape of the Earth whose centroid is located at the Earth’s centre of mass.

Ellipsoidal Height -

A height measured, using GNSS technology, from the surface of a reference ellipsoid to a point on the Earth’s surface.

Orthometric Height -

A height measured along the plumb line from the Geoid to a point on the Earth’s surface.

NAD83-CSRS -

North American Datum 1983 – Canadian Spatial Reference System – a modern 3-D realization of NAD83.

NAD83-ORIG -

North American Datum 1983 – Original/v0 – the first realization of NAD83.

CCOG -

Canadian Council On Geomatics.

CGRSC -

Canadian Geodetic Reference Sub-Committee – a Sub-Committee of CCOG. 

NTv2 -

National Transformation version 2.

TRX -

TRX is a coordinate transformation tool that allows you to transform coordinates between epochs of NAD83-CSRS.

HT2.0 -

Height Transformation version 2.0.

GPS·H -

GPS Height Transformation – transfer between epochs.

MIRB -

Mapping and Information Resources Branch.

CMID -

Corporate Management and Information Division.

10. Appendices

10.1 Normative references

• Governance and Management of Information Technology Directive (for OPS employees/internal users)
• GO-IT Standards

Note: A normative reference specifies a supporting document or GO-IT Standard (in the case of the Government of Ontario's I&IT infrastructure, often another OPS I&IT authorized publication) that must be read to fully understand or implement the subject matter of the main GO-IT Standard. Such authoritative or de facto references may be external and may, or may not be, owned/controlled by the GO-IT Standard owner.

10.2 Informative references

• Ontario Transformation version 2 (NTv2) User’s Guide

This user's guide covers the operation of the NTv2 software, and the formats for input and output of coordinate data.

• National Transformation Version 2 (NTv2) Grid Shift Files for Ontario are available through the Ontario GeoHub @: NTv2 Grid Shift Files for Ontario- Ontario GeoHub
• For information regarding HTv2.0 visit: NAD83. (CSRS) v7
• For information regarding GPS·H visit: GPS·H
• For information regarding TRX visit: TRX

Note: An informative reference is not normative; rather, it provides only additional background information.