on the administration of the
Survey Co-ordination Act 1958
Prepared by John E Tulloch, Surveyor-General of Victoria
Front cover: GNSS survey of Round Hill trigonometric beacon, with Mount Piper in the background
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 2015
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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 2014–2015 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. While responsibility for this legislation remained with the Minister for Planning following machinery of government changes in December2014, on 1January2015, Land Victoria, incorporating the Office of Surveyor-General Victoria, became part of the Department of Environment, Land, Water and Planning.
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 increasingly 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 survey 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 survey 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
While no changes were made to the Survey Co-ordination Act 1958 during the reporting period, minor consequential amendments were made to the Survey Co-ordination Regulations 2014 via the Survey Co-ordination Amendment Regulations 2015. This resulted from the making of the Surveying (Cadastral Surveys) Regulations 2015, which replaced the Surveying (Cadastral Surveys) Regulations 2005. The amendments to the Survey Co-ordination Regulations 2014 were minor and updated references to the Surveying (Cadastral Surveys) Regulations 2015. Both new regulations were made on 2June2015 and commenced operation on 14June2015.
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. Conformance 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 2005; 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 (CORS) sites. 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 is a rapidly evolving technology and is increasingly being 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. Fundamentally, Victoria’s GNSS CORS contributes to the establishment and realisation of the International Terrestrial Reference Frame (ITRF) and underpins 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 by the department’s Information Services Division (ISD), GPSnet is comprised of GNSS CORS sites funded by the Victorian Government and partly by the federal government’s AuScope and ‘GNSS in Schools’ programs (see section 5). It is supported by several local government agencies and other private interests through numerous formal tenure arrangements. The GNSS base station network consists of 115 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 the Internet, which allows industry and the general public to access this information free of charge. The marks of greatest significance are protected and maintained to provide a physical means of traceability to the respective GDA94 and AHD71 positioning and vertical datums.
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 a major upgrade of its online systems (discussed in section7 Survey Marks Enquiry Service). Work continues to integrate the HSMs installed at all National Levelling Network (NLN) junction points within the GDA94 and AHD71 network adjustments through GNSS and levelling surveys. 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. Through funding received from another federal government initiative (‘GNSS in Schools’) designed to increase the awareness of geography and positioning in secondary schools across Australia, five new GNSS CORS sites have been installed at Ballarat Grammar School, Coburg Senior High School, Cranbourne Secondary College, John Monash Science School and Werribee Secondary College.
Map Grid of Australia 1994 (MGA94) survey control with suitable SCN marks was provided for 15 specific cadastral surveys during 2014–15 to enable each land parcel within those surveys to be accurately depicted within the digital map base – Vicmap Property, on a priority basis. In excess of 65 high-precision GNSS surveys were undertaken throughout Victoria 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 conjunction with the Intergovernmental Committee on Surveying and Mapping (ICSM) and other jurisdiction members, OSGV continues to progress the development of the eGeodesy project and has made considerable progress in its implementation within Land Victoria. Akin to the objectives of ePlan (discussed in section 9 of this report – Co-ordination of Surveys), 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. In addition, Victoria contributed to a major review and update of the GDA94 Technical Manual and to the update of ICSM’s Standards and Practices for Control Surveys (SP1), version 2.1. SP1 is accessible via www.icsm.gov.au> Standards and Practices for Control Surveys (SP1).
In July 2014, a consultation draft version of Victoria’s geodetic strategy, which focusses on the development and maintenance of Victoria’s geodetic infrastructure over the next five years, was released to a selection of Victorian geodetic infrastructure stakeholders (in government, industry and academic sectors). OSGV received positive constructive feedback and has refined the strategy accordingly. It is expected that this strategy will be released in the first half of the next reporting period.
Due to the static nature of the data associated with the majority of PCMs and the inability to include them within an adjustment of that data to enhance the spatial accuracy of their position and assess the certainty of the data, the Surveyor-General’s policy on recording PCM data within SMES was varied in September 2014. Accordingly, PCM information shown in previous reports has not been included in this report.
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 or compromised with marks destroyed as a consequence of infrastructure construction. Following the major re-adjustment of the SCN in June 2014, the SCN has seen two incremental adjustment updates (September 2014 and June 2015), which have resulted in improvements to co-ordinate and uncertainty values for the majority of SCN marks.
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, which are all maintained by OSGV. 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. Victoria’s AHD71 network of spirit levelling measurements was readjusted in June 2014 and has led to several improvements to the published values.
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 research project focussed on the development of a next generation datum (see section 6.1). In addition, Victoria continues to make good progress towards finalising its contribution to the national datum re-adjustment, scheduled for mid-to late-2015.