on the administration of the
Survey Co-ordination Act 1958
Prepared by John E Tulloch, Surveyor-General of Victoria
Front cover: Geodetic Road signpost, Horsham
Office of Surveyor-General Victoria
Land Victoria
Department of Environment, Land, Water and Planning
570 Bourke Street
Melbourne VIC 3000
Phone: (03) 8636 2525
Fax: (03) 8636 2776
Email:
Web: www.delwp.vic.gov.au>Property and land titles>Surveying
© The State of Victoria Department of Environment, Land, Water and Planning 2016
This work is licensed under a Creative Commons Attribution 4.0 Australia licence. You are free to re-use the work under that licence, on the condition that you credit the State of Victoria as author. The licence does not apply to any images, photographs or branding, including the Victorian Coat of Arms, the Victorian Government logo and the Department of Environment, Land, Water and Planning logo. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/
Accessibility
If you would like to receive this publication in an alternative format, please telephone the DELWP Customer Service Centre on 136186, email or via the National Relay Service on 133 677 www.relayservice.com.au.
Disclaimer
This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
Contents
1 Introduction 2
2 Legislation and regulations 2
3 Survey Control Network (sections 6, 12, 14–18, 21A) 3
4 Continuously Operating Reference Stations (CORS) Network Positioning 3
5 Geodetic infrastructure 4
6 Datum (section 21A) 5
7 Survey Marks Enquiry Service (SMES) (sections 15–18) 6
8 Central Plan Office (CPO) (sections 4, 8–11) 6
9 Co-ordination of surveys (sections 6, 12–14, 19) 7
10 Verification surveys (section 6) 8
11 Appendix: Operational statistics 2015-2016 9
Note: Items in brackets denote the relevant sections of the Survey Co-ordination Act 1958
Surveyor-General of Victoria – Practice Directives, September 2014 – Edition 2
2
1 Introduction
The Survey Co-ordination Act 1958 and the Surveying Act 2004 provide the primary legislative framework for land surveyors undertaking geodetic and cadastral surveys.
Land surveying is integral to land ownership and development, and also supports a wider range of activities related to the environment, communications, transportation and infrastructure. In conjunction with locating and placing survey marks with high positional accuracy on the earth's surface, land surveyors use satellite positioning technology to create spatial information that is applied in geographic information systems and location-based services. As a result of the widespread adoption of spatial information technology, the information created by land surveyors is being utilised by a diverse range of sectors in government, industry and the community.
The underlying principles of the Survey Co-ordination Act 1958 are to establish an efficient system that:
· minimises duplication of cadastral surveying work and reduces overall costs of surveys to the community;
· provides for the lodgement of plans and surveys by departments and authorities in the Central Plan Office (CPO);
· controls surveying procedures and stipulates accuracy standards for compliance by land surveyors and the spatial industry; and
· establishes Victoria’s network of permanent survey marks to support the national geodetic and cadastral (property title, rights, restrictions and responsibilities) infrastructure.
The Survey Co-ordination Act 1958 was implemented to co-ordinate land surveying and mapping activities in Victoria and facilitate cooperation with the Commonwealth of Australia in relation to a National Mapping Scheme. The Survey Co-ordination Act 1958 directs the department to maintain a Central Plan Office (CPO). While the administration of the CPO is performed by Land Registration Services within Land Victoria, the supervision of the CPO is a function of the Surveyor-General.
The CPO continues to operate in a ‘virtual’ form as a repository for registered legislative (LEGL) plans; survey plans, survey information and Crown land dealings. The plan and survey information registered by the CPO is available from Land Victoria’s online information service. Public Record Office Victoria (PROV) increasingly acts as a repository for many of the paper records that were traditionally held by the CPO.
2 Legislation and regulations
No changes have been made to the Survey Co-ordination Act 1958 or the Survey Co-ordination Regulations 2014 during the reporting period.
The Surveying Act 2004 includes provisions relevant to survey co-ordination activities and the specification of the statutory functions of the Surveyor-General. The Surveying (Cadastral Surveys) Regulations 2015, pursuant to the Surveying Act 2004, incorporate standards for controlling the accuracy of cadastral surveys to maintain the integrity of the cadastre and the requirements for maintaining consistency in cadastral surveys. Compliance with these standards by the land surveying profession is monitored by the Office of Surveyor-General Victoria’s (OSGV) survey audit program.
3 Survey Control Network (sections 6, 12, 14–18, 21A)
The Survey Control Network (SCN) is defined in the Surveying Act 2004 as ‘the geodetic system that provides spatial references in Victoria by –
(a) permanent marks and survey marks adopted or established in accordance with the Survey Co-ordination Act 1958; and
(b) survey marks established under this Act or the Surveying (Cadastral Surveys) Regulations 2015; and
(c) the application of data obtained from global navigation satellite systems.’
Victoria’s SCN provides Victoria’s realisation of Australia’s positioning and vertical datums – the Geocentric Datum of Australia (GDA94) and the Australian Height Datum (AHD71), respectively.
The SCN is used as the positioning framework upon which Victoria’s land registration and spatial information systems are based, typical of all Australian jurisdictions and most developed nations.
The SCN currently comprises approximately 200,000 survey marks, whose location and/or height are known to varying degrees of accuracy. The marks include standard brass plaque-in-concrete Permanent Marks (PMs), deep driven High Stability Marks (HSMs), Primary Cadastral Marks (PCMs) and the network of Global Navigation Satellite Systems (GNSS) Continuously Operating Reference Stations (CORS). See Appendix for survey mark statistics.
Detailed information and metadata associated with the survey marks that comprise the SCN can be accessed via the Survey Marks Enquiry Service (SMES) (see section 7 of this report).
4 Continuously Operating Reference Stations (CORS) Network Positioning
The Victorian Government has a strategy of embracing GNSS CORS technology as a means of delivering high precision positioning information and services. GNSS CORS are used in government, commercial, academic, scientific and societal applications to provide high-accuracy, real-time positioning relative to Australia’s national GDA94 and AHD71 datums. Victoria’s GNSS CORS contribute to the establishment and realisation of the International Terrestrial Reference Frame (ITRF) and underpin the maintenance and enhancement of GDA94 in Victoria.
High precision positioning information and services are made available in Victoria through the operation of a state-wide network of GNSS CORS sites known collectively as Vicmap Position – GPSnet.
Principally hosted and maintained during the reporting period by the Department’s Information Services Division (ISD), GPSnet is comprised of GNSS CORS sites funded by the Victorian Government and by the federal government’s AuScope and ‘GNSS in Schools’ programs (see section 5 of this report). It is supported by several local government agencies and other private interests through numerous formal tenure arrangements. The GNSS base station network consists of 117 continuously operating GNSS base stations sited across the state, all of which provide users with access to real-time and archived data streams.
5 Geodetic infrastructure
The Survey Co-ordination Act 1958 is the principal legislation dealing with Victoria’s geodetic infrastructure, also referred to as the SCN, which is comprised of a network of physical ground marks; a network of GNSS CORS sites and hosting technology; information about those GNSS CORS and marks; geodetic analysis and processing software; corporate systems for the management and delivery of positioning information; and various policies, standards and guidelines. The co-ordinate values of Victoria’s GNSS CORS and ground marks are held in a database accessible from SMES (discussed in section7 of this report), which allows industry and the general public to access this information free of charge.
OSGV continues to maintain and enhance the SCN through the installation of new marks, collection of new observations, routine statistical analysis, ongoing improvements to network adjustment software, routine mark maintenance activities and maintenance of its online systems. The integration of HSMs installed at all National Levelling Network (NLN) junction points with the GDA94 and AHD71 network adjustments through GNSS and levelling surveys was completed early in this reporting period and this system is now in a maintenance phase. The national correction surface between the ellipsoid and AHD71 (known as AUSGeoid) continues to provide reliable corrections to heights obtained through the use of GNSS to produce AHD71 heights. OSGV continues to address localised AUSGeoid problems in Victoria through routine GNSS and levelling surveys.
Victoria continues to support the federal government’s National Collaborative Research Infrastructure Strategy (NCRIS). In accordance with provisions of the Survey Co-ordination Act 1958 that relate to the co-ordination of work on national geodetic infrastructure, Victoria contributes to the NCRIS AuScope program through the collaboration of OSGV and ISD. Victoria’s 10 AuScope stations are an integral component of the geodetic network and serve as the high-fidelity ‘backbone’ for GDA94 and AUSGeoid in Victoria.
Map Grid of Australia 1994 (MGA94) survey control with suitable SCN marks was provided for 10 specific cadastral surveys during 2015-16 to enable each land parcel within those surveys to be accurately depicted within the digital map base – Vicmap Property. Throughout Victoria, 67 high-precision GNSS surveys were undertaken to improve and/or densify the SCN; to improve the alignment of published SCN co-ordinates with positioning derived from the GNSS CORS network; and to improve the quality of AUSGeoid.
In November 2015, a high precision survey was conducted over a stable network of seismic monitoring marks across the Otway and Gippsland regions. Following the initial survey in November 2011, this is the second survey to be undertaken over this network, which, when combined with future surveys at four-year intervals, will be used to measure deformation and seismic activity in the respective regions.
In conjunction with the Intergovernmental Committee on Surveying and Mapping (ICSM) and other jurisdiction members, OSGV continues to contribute to the development of the eGeodesy project. Akin to the objectives of ePlan (discussed in section 9 of this report), eGeodesy is an initiative to standardise the capture and exchange of geodetic information to automate network adjustment processes, and to support datum development and maintenance. During the current reporting period, the project produced a new version of the GeodesyML schema (which has been adopted by the International GNSS Service (IGS) Governing Board as the basis for its GNSS Site Log standard), and has grown to include participation from various international geodetic agencies.
After receiving positive constructive feedback from Victorian geodetic infrastructure stakeholders (in government, industry and academic sectors), the ‘Strategy for Victoria’s positioning system 2016-2020’ was launched by Deputy Secretary Local Infrastructure, Terry Garwood, on 16 December 2015. The strategy focusses on the development and maintenance of Victoria’s geodetic infrastructure over the next five years.
6 Datum (section 21A)
The realisation of the GDA94 national positioning datum in Victoria is based upon a large set of measurements observed across Victoria’s network of SCN ground marks. Due to several factors, the realisation of GDA94 through the SCN is subject to continual change and enhancement. As new land development occurs, the SCN is either improved with new marks added or compromised as old marks are destroyed as a consequence of infrastructure construction. Based upon a number of high precision GNSS surveys undertaken across the state over the current reporting period, the SCN was readjusted in April 2016, resulting in numerous coordinate and uncertainty improvements.
The realisation of the AHD71 national height datum is provided by Victoria’s extensive levelling network, comprised of the NLN junction points and other survey marks throughout the state. AHD71 is derived by reference to a system of tide gauges around the coastline of Australia maintained by the National Tidal Centre, within the Bureau of Meteorology. Whilst there are no plans to upgrade AHD71 at a national level, several spirit levelling surveys have been undertaken across the state to support urban and rural infrastructure projects and to remedy large anomalies resulting from long-term subsidence and deformation.
In collaboration with ISD, OSGV continues to contribute to the Asia Pacific Reference Frame (APREF) project through the provision of GNSS CORS data and data analysis. The broad objective of APREF is to create and maintain an accurate and densely realised geodetic framework across the Asia Pacific region based on continuous observation and analysis of GNSS data, upon which the development and enhancement of future datums in Australia will be based. The APREF project affords OSGV a capacity to contribute to the monitoring of local and regional crustal deformation across Victoria, and significantly improve the precision and reliability of Victoria’s SCN.
6.1 Datum modernisation
For several years, the government jurisdictions that form the ICSM PCG have undertaken a range of investigative activities to address the apparent and growing weaknesses in Australia’s positioning datum, GDA94, and the ongoing trends in precise positioning. In early 2015, this effort culminated in the development of a comprehensive roadmap to modernise GDA94 and recommended a progressive, two-staged approach to its implementation. The first step is proposed to commence on 1 January 2017 and the second step on 1 January 2020. The new datum will be known as GDA2020, and will be complimented with a new version of AUSGeoid, known as AUSGeoid2020.
Through its involvement with the Permanent Committee on Geodesy (PCG) of the ICSM and an involvement with the federal government’s Cooperative Research Centre for Spatial Information (CRCSI), OSGV continues to actively participate in a project focussed on the development of a next generation positioning datum. Victoria finalised its first-draft contribution to the national datum re-adjustment in April 2016, and is now working with other jurisdictions on achieving the remaining technical milestones on the datum modernisation project plan.