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THE EVOLUTION OF NOVA SCOTIA’S COORDINATE REFERENCING SYSTEMS

Jason Bond, Coordinate Control Officer, Department of Internal Services, Province of Nova Scotia William Robertson, Manager of the Control Surveys Division (Retired), Land Registration and Information Service, Council of Maritime Premiers

Despite its rich history, the evolution of the coordinate referencing system in Nova Scotia has not been welldocumented. As the foundation for the property boundary fabric and land registration system for the province,it is critical that this knowledge is maintained. It is the key to being able to link surveys of the past with thepres ent. This research strives to capture important coordinate referencing knowledge from those that haveworked with the system and have since retired from the Nova Scotia provincial government or former LandRegistration and Information Service.

A detailed review of documentation discussing various historical aspects of coordinate referencing inNova Scotia was conducted. Personnel involved with the implementation of the systems were interviewed topro vide first-hand accounts of operational details. This information is captured and is presented chronologically.An outlook on the future of the coordinate referencing program is also discussed.

Introduction

Coordinate referencing systems help to addressfundamental societal needs by providing infrastruc-ture to answer the questions “Where am I?” and“Where should I be?” Land administration, propertymanagement, engineering, construction and mappingare examples of activities that depend on an underly-ing coordinate referencing system that is reliable andaccurate. Well-established coordinate referencingsystems enable asset management and development,which are critical components for sound governance.

Nova Scotia has a rich history in its coordinatereferencing program that it has implemented andmaintained since the late 1960s. There are at leastthree distinct coordinate referencing systems thathave been implemented in the province. For overthree decades, Nova Scotia Land Surveyors (NSLSs)have been regulated to connect their surveys to one

of the province’s coordinate referencing systems.The practice of relating surveys to a coordinate ref er -encing system allows for meaningful spatialrela tion ships to be defined between parcels of property.

New coordinate referencing systems aredevel oped as technology and knowledge advancesand the needs of users become more demanding. Asthousands of survey plans are created over time in aparticular coordinate referencing system, it is criticalthat knowledge about each system be well doc u-ment ed and understood. Presently, several provincesin Canada have a single person managing the opera-tions of their respective coordinate referencing sys-tem. Many of these people have accumulated decadesof knowledge about the inner workings of theirrespective systems. This knowledge base is typicallynot found outside the organization. As generations

dx.doi.org/10.5623/cig2015-403 GEOMATICA Vol. 69, No. 4, 2015, pp. 407 to 418

Malgré sa riche histoire, l’évolution du système de référencement de coordonnées en Nouvelle-Écossen’a pas été bien documentée. À titre de fondement du système d’enregistrement foncier et du canevascadas tral de la province, il est essentiel que ces connaissances soient conservées. C’est l’élément clé quipermet de relier les levés du passé à aujourd’hui. La présente recherche vise à saisir des con nais sancesimportantes sur le référencement des coordonnées auprès des personnes qui ont travaillé avec le système etqui ont pris leur retraite du gouvernement provincial de la Nouvelle-Écosse ou de l’an cien Service ducadastre et de l'information foncière.

Un examen détaillé de la documentation traitant des divers aspects historiques du référencement descoordonnées en Nouvelle-Écosse a été effectué. Les employés impliqués dans la mise en œuvre des systèmesont été interrogés pour obtenir des témoignages de première main au sujet des détails opérationnels. Cetteinformation est saisie et présentée de manière chronologique. Un aperçu de l’avenir du programme deréférencement des coordonnées fait également l’objet d’une discussion.

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change, the threat of losing a critical knowledge basethat serves as the foundation for geographic informa-tion is very real. Some provinces have lost theirgeo detic capacity altogether.

This paper strives to document informationabout the historic and current coordinate referencingsystems in Nova Scotia. A summary of key terminol-ogy is presented, followed by a chronological reviewof the coordinate referencing systems that have beenimplemented. An outlook on the future of thecoor di nate referencing program is also discussed.

Coordinate ReferencingConcepts and Terminology

A review of common coordinate referencingconcepts and technology is presented before review-ing the evolution of the province’s coordinateref er encing systems. For a more detailed discussionon these topics, see Junkins and Garrard [1998].

Coordinate systems provide a framework tospatially relate features and objects. In their simplestform, one can relate to a two-dimensional pla narcoordinate system with X and Y axis. Mathematicalmodels are used to project the spher i cal earth onto asheet of paper to allow a pla nar coordinate system tobe used. Various projection methodologies exist,each having different distortion characteristics. TheUniversal Transverse Mercator (UTM) projection isan example of a pro jection commonly used.

Coordinate systems need to be positioned andoriented to serve as a coordinate referencing sys-tem. This is achieved by defining the location of theorigin of the coordinate system and by defining theorientation of its axis. Since the earth is three-dimensional, a three-dimensional coordinatesys tem is used for geodetic referencing, with thefollowing typical parameters:

• The origin is defined as the best approximationof the earth’s centre of mass (i.e., geocentric).

• The Z-axis is parallel to the earth’s axis ofrota tion.

• The positive X-axis intersects the Greenwichmeridian.

This type of three-dimensional coordinatesys tems is known as a Conventional TerrestrialReference System (CTRS). For completeness, acoordinate referencing system must also include anyphysical constants, parameters and specifications thatare required to calculate position using that system.

By adding a reference shape to the coordinatereferencing system to represent the earth (generallyan ellipsoid), a geodetic datum is defined.

Examples of reference shapes include Clarke’sEllipsoid of 1866 (used for the North AmericanDatum of 1927) and the GRS 80 Ellipsoid (used forthe North American Datum of 1983).

A coordinate referencing system may allow forvarious coordinate types to be computed. Examplesof different types include:

• Spherical coordinates (geographic latitude andlongitude)

• Cartesian coordinates (XYZ)• Planar coordinates (based on a mapping pro-

jection such at 6 degree Universal TransverseMercator or 3 degree Modified TransverseMercator)

A physical representation of a coordinatesys tem through a series of survey or control monu-ments with assigned coordinate values, known as areference frame, allows users to spatially relatenat u ral features and structures to the coordinate ref-erencing system. Global Navigation SatelliteSystems (GNSS) have extended this traditional con-cept. Conceptually, the satellites from GNSS serveas monuments with assigned coordinates and canserve as a gateway to a specific coordinate referencingsystem. The reference frame makes the coordinatereferencing system tangible and accessible.

Over time, new observation data may beacquired for the reference frame. The new dataallows for the mitigation of existing errors and distor-tions and improvements in accuracies. The updatedcoordinates represent new realizations of the coordi-nate referencing system [Craymer 2006]. There arevarious ways in which a coordinate referencing sys-tem may be improved, including: 1) better estimationof the earth’s centre of mass; 2) better representationof the shape of the earth; 3) better technology to makereference frame observations; and 4) higher densityof reference frame monuments.

As technology has evolved, the accuracy ofcoordinate referencing systems has also generallyimproved. The adoption of a new coordinate refer-encing system poses numerous challenges for ajurisdiction in terms of the education of users,updating coordinate values for the reference frameand creating tools to facilitate the transformation ofexisting data sets to the new system. Because of thecosts associated with addressing these challenges,there must typically be significant benefit to mov-ing forward before a jurisdiction would consideradopting a new system.

The term “spatial referencing system” is usedboth by the Canadian Geodetic Survey (CGS) andthe United States’ National Geodetic Survey(NGS) to describe federal reference systems. They

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are referred to as the Canadian Spatial ReferencingSystem (CSRS) and National Spatial ReferenceSystem (NSRS), respectively. The scope of theirwork is generally broader than that of the provinces’efforts since it includes such activities as measuringgeopotential, acceleration of gravity, deflections ofthe vertical, GNSS orbits, tectonic velocity modelsand orientation, scale and offset information relatingfederal reference systems to international referencesystems. In this paper, the term “spatial referencingsystem” is reserved for these types of programs thatare generally feder al in nature. In Nova Scotia, thefocus is on the geometric, coordinate relationshipsand, accordingly, the program is termed the NovaScotia Coordinate Referencing System (NSCRS).The NSCRS utilizes the provincetools, models andappli cations to calculate and maintain highaccu ra cy coordinates.

The Federal FoundationAs in most provinces in Canada, the foun da tion

for Nova Scotia’s coordinate systems referencingoriginates with initiatives led by the federal gov ern-ment. For a comprehensive review of these initia-tives, see McGrath and Sebert [1999]. Being acoastal province with strategic location, NovaScotia benefitted from the charting work of theHydrographic Service of the Royal Navy conductedduring the latter half of the nineteenth century. Thenavy’s work served as control for the early medium-scale mapping for the province [Sebert 1999].

The Geological Survey of Canada was alsoinvolved in surveying and mapping activities inNova Scotia from 1880 onward. By 1910, it hadcompleted a 91-sheet series of 1-inch maps (1 inchto 1 mile scale) covering all of the province exceptthe southwest tip. These maps served as a base forthe 20-chain and 40-chain (1:15 480 and 1:31 680)provincial resource development maps. In 1922, theBritish Geographic Section of the General Staff(GSGS) and the Topographical Survey, Departmentof the Interior, began topographic mapping at the 1-inch to 1-mile scale. This work was complet ed in1956 and eliminated the need for provincial topo-graphic work until the demand for larger scaleresource mapping arose in the 1960s [Sebert 1999].

In 1913, the North American Datum (NAD) wasdefined and officially adopted for use by Canada, theUnited States and Mexico. It was renamed NAD27following a major readjustment of much of the NorthAmerican Network. NAD27 was a non-geocentricreference system which used the Clarke Ellipsoid of

1866. The primary reference point of the coordinatesystem was defined as Meade’s Ranch in the state ofKansas. The coor di nates of this site were used in thecalculation of triangulation networks throughoutNorth America [Gillis et al. 2000].

In 1935, the Canadian Geodetic Vertical Datumof 1928 (CGVD28) was officially adopted by anOrder in Council. CGVD28 is a tidal datum based onthe mean water level at five tide gauges: Yarmouthand Halifax on the Atlantic Ocean; Pointe-au-Père onthe St. Lawrence River; and Vancouver and PrinceRupert on the Pacific Ocean. Additionally, a bench-mark in Rouses Point, New York, is used as a fixedvertical constraint. The CGVD28 framework cur-rently consists of 94 000 benchmarks across thecountry that have been measured using preciselev el ling measurements [NRCan 2015A].

Most geodetic work performed prior to theSecond World War was done by two federal organ-izations [Sebert 1999]: the Geodetic Survey ofCanada (now referred to as Canadian GeodeticSurvey), which was formed in 1908 and is respon-sible for maintaining the CSRS; and the GravitySection of the Geological Survey of Canada, whichis responsible for gravity data. It was founded in1842 and is Canada’s oldest scientific agency[NRCan 2015B].

In 1946, the Canadian spatial referencing systemwas based upon a horizontal triangulation network ofabout 19 400 km and a vertical control network ofapproximately 63 000 km of precise levelling. Overthe next decade, about 7300 km was added to theconventional triangulation network and 13 000 kmwas added to the precise levelling network. Theintroduction of precise Electromagnetic DistanceMeasurement (EDM) technology in the mid-1950sgreatly accelerated Geodetic Survey’s work and, by1959, Canada had a continuous coast-to-coast trian-gulation network [Babbage and Roberts 1999]. Theuse of EDM technology also had another significantimpact—it began to reveal distortions in NAD27.The distortions were caused by non-rigorous adjust-ment procedures, poor network geometry and thelack of an accurate geoid model to make geodeticcorrections to the observations [Gillis et al. 2000].

Technical Impact of EarlyFederal Geodetic Work

The federal adjustment of its triangulationnet works brought NAD27 to the Maritimes. Theinitial NAD27 adjustments used United StatesCoast and Geodetic Surveys stations at Chamcook

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and Trescott Rock at the western end of theBay  of  Fundy as constraints [Gillis et al. 2000].Despite the aforementioned weaknesses in NAD27,it served as the primary coordinate referencingsys tem for Nova Scotia for several decades.

The federal adjustment of its precise levellingnetworks brought CGVD28 to the Maritimes.CGVD28 has been the primary source of orthome-tric heights in Nova Scotia for almost 100 years. Itwas not until 2015 that CGVD28 heights on someNova Scotia Control Monuments (NSCMs) wereupdated with new Canadian Vertical Datum of2013 (CGVD2013) geoid-based, heights.

Atlantic Provinces Surveyingand Mapping Program

In the 1960s, it had become apparent thateco nomic development in the Atlantic provinceswas being hindered by an outdated land registrationsystem and by a poor mapping compilation fromwhich to plan resource development. The fundingrequired to update provincial mapping resourcesgreatly exceeded the capacity of the Atlanticprovinces. In 1966, a proposal was submitted to theAtlantic Development Board by Willis Roberts,Director of Surveys of New Brunswick at that time.The visionary proposed the four-phase plan sum-marized in Table 1 that would modernize surveyingand mapping in the Atlantic region. It was estimatedthat it would take 35 years to complete the planwith federal assistance, or twice as long withoutsupport [Sebert 1999].

As a result of Robert’s proposal, Nova Scotia’sfirst coordinate referencing initiative was born onMarch 22, 1968, when the Atlantic DevelopmentBoard approved the concept of establishing theAtlantic Provinces Surveying and Mapping Program(APSAMP). Funding of the program was stalled bythe formation of the newly-created federal

Department of Regional Economic Expansion(DREE). DREE supported 90% of the cost of thepro gram ($12 million) from 1969 to 1972[Sebert 1999].

Technical Impact of theAPSAMP Effort

In 1968, coordinates for the first-order networkmonuments in the province were calculated byGeodetic Survey Division (GSD) using the NAD27datum. These values were distributed in imperialunits. Rigorous geodetic techniques were not uti-lized for this adjustment (observations were not fullyreduced), which resulted in network distortions.

In order to support the development of thesec ond-order survey network as set out in Phase 1 ofthe APSAMP, the first-order federal network requiredsignificant expansion in Nova Scotia. GSD estab-lished first-order survey monuments in the AnnapolisValley region in 1969. A military survey crew alsoestablished first-order survey monuments in Hants,Kings, Halifax and Lunenburg counties that year. In1970, further expansion occurred in Halifax andGuysborough counties. Network expansion wouldcontinue throughout Nova Scotia over the next twoyears until a satisfactory density was achieved. In1972, another federal adjustment was performedusing more rigorous geodetic data-handlingtech niques and a network of approximately 100 first-order federal survey monuments. A stronger geomet-ric network resulted in a more consistent networkadjustment across the province [Flemming 2014].

Although the APSAMP led to commonstrate gies for managing and funding surveying andmapping initiatives in the Atlantic provinces, eachprovince still set its own operational standards [LRIS1977]. In Nova Scotia, APSAMP was implementedthrough the Control Surveys, Surveys and MappingDivision of the Department of Lands and Forests.

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Phase Description

1. Surveying Placing of survey monuments throughout the Atlantic Provinces at a densityconsistent with the population

2. Mapping Provincial 1:5000, 1:10 000 Municipal mapping at 1:1200, 1:2400, 1:4800 (imperial) and 1:1000, 1:2000,1:2500 and 1:5000 (metric)

3. Land Titles Design and implementation of an improved land titles registration system

4. Land Data Bank Compilation of all land information into a database including the ownership,market value and geographical characteristics of all registered land parcelsand Crown lands

Table 1: Four-phase plan for modernizing surveying and mapping in the Atlantic region [Sebert 1999; LRIS 1977].

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The Division placed a total of 8000 sec ond-orderNSCMs during the first five years of operation. Mostof these monuments were located throughout thedeveloped areas of the province [NSLUC 1995].

Land Registration andInformation Service

During the mid-1960s, New Brunswick, NovaScotia and Prince Edward Island were investigatingways of conducting interprovincial cooperation. In1965, the Maritime governments proposed theMaritime Union Study to formally explore opportu-nities for integrating government services and toaddress the question of whether or not the Maritimeprovinces should unite into a single province.Although a plan for political union was rejected, thethree provincial governments agreed to establish theCouncil of Maritime Premiers (CMP) to provide aframework for implementing joint initiatives. Onekey interest for such initiatives were opportunitiesfor collaboration in delivering land use and tenureprograms [LRIS 1977].

In April of 1972, APSAMP was extended for anadditional year with each province managing itsaffairs independently. At this time, Newfoundlanddecided to withdraw from the arrangement and

negotiated a separate agreement with DREE.Roberts pro posed that the CMP assume the admin-istration of a new program called the LandRegistration and Information Service (LRIS)[Sebert 1999]. The proposal was approved and inApril of 1973, the staff previously employed onAPSAMP work by the provinces formed the core ofthe new organization [LRIS 1977].

LRIS was designed to have the same fourphases as APSAMP and was also funded throughDREE. Experience had shown that the two-yearfunding periods applied for APSAMP were tooshort for the magnitude of the project. Roberts wasable to negotiate a five-year plan for LRIS, whichwas the limit for the program at that time. It wasassumed that additional five-year plans would fol-low until the program was fully executed in 30 years.At the end of the first five-year period in 1977,DREE informed the CMP that only one additionalyear’s funding would be provided, and fundingwould not be available for another five years. From1968 until 1978, DREE had contributed approxi-mately $34 million to the APSAMP and LRISpro grams [Sebert 1999].

The coordinate referencing system put in placethrough Phase 1 of LRIS was state-of-the-art. Thesystem was commonly referred to as theNova Scotia Coordinate Control System (NSCCS)and its reference frame is illustrated in Figure 1.

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Figure 1: NSCCS reference frame.

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Practically every inhabited road in Nova Scotia hadsurvey monuments with 1-km spacing or less. Theinfrastructure was also extended to Sable Island in theearly 1980s. For a more detailed discussion on coor-dinate referencing on Sable Island, see Bond [2015].

EDM technologies were becoming morecom monplace during the 1970s and were being usedon many surveying projects, including the establish-ment of the NSCCS reference frame. For optimalperformance, a calibration procedure was used toaccount for the non-coincidence of the electricalcentre of the EDM with its centring mark. For thatpurpose, GSD and LRIS cooperated to establishthree calibration baselines in Nova Scotia nearLawrencetown, Halifax and Port Hawkesbury.

In southwest Nova Scotia, inertial surveysys tems were used to densify the survey monumentinfrastructure. This was a collaborative effortbetween LRIS, the Nova Scotia Department ofLands and Forests and the federal Department ofEnergy Mines and Resources. These monumentsappear as distinct lines across southwest NovaScotia and were referred to as ISS points.

Elevations for the second-order survey networkwere derived from first-order federal benchmarks.Levelling was typically only performed betweenfirst-order benchmarks and the nearest second-ordersurvey monument. Elevations were determined forthe rest of the network by measuring the slope dis-tance and near simultaneous zenith dis tancesbetween monuments.

With over 20 000 NSCMs put in place to real izethe NSCCS reference frame, it was not long beforechallenges associated with maintaining and manag-ing this infrastructure became apparent. As newdevelopments took place, it became necessary todensify and measure to new NSCMs to expand thenetwork. It was estimated in the early 1980s that 2%of NSCMs were being destroyed each year and thatan additional 1% were required for densification.Consequently, a five-year work program was imple-mented in 1981 to address these needs [Dept. ofLands and Forests 1983].

It was recognized early on that road constructionwas one of the largest offenders for destroyingsur vey monument infrastructure. To help address thecost of replacing destroyed monuments, aMonument Trust Fund was established in 1982 toallow the Department of Transportation andCommunications to transfer funds to cover the costof replacing monuments. More than 425 monumentswere replaced using this fund [NSLUC 1995].

By 1983, 23 000 NSCMs had been installed inNova Scotia. Unfortunately, the 1983–1984 budgetcut maintenance of the NSCCS network. Despite

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cutbacks, the overall quality of the coordinateref er encing system remained high for several years,largely because of the abundance of NSCMs. By theend of the 1980s, however, it was apparent that thelack of funding to maintain the infrastructure wastaking its toll. In 1989, a proposal was put forward todo a single cycle of maintenance on the ref erenceframe. This involved inspecting and densifying theexisting network over a five-year period, at a totalcost of $2.25 million. The proposal was rejected dueto the high cost [NSLUC 1995].

As LRIS was struggling to maintain the NSCCS,the Global Positioning System (GPS) was emergingas a new technology to perform geodetic surveys.GPS offered higher accuracy measurements overlonger distances than conventional theodolite andEDM technologies. Additionally, GPS did not requireline-of-sight between adjoining monuments. In 1986,LRIS commissioned a study for control surveys forLRIS. The main recommendation of that study wasthat the LRIS should develop expertise in GPS so thatit would be immediately able to take advantage of thetechnology [Hamilton and Doig 1993]. As GPSbecame more commonplace through the 1990s, itbegan to reveal distortions in the NSCCS, which wasobserved using conventional survey instrumentation.As was the case 20 years prior, technology dictatedthat a higher accuracy coordinate referencing systemwould be required to support it.

Perhaps the biggest challenge with the LRISSurveys and Mapping program was that it lacked asustainable model to maintain the infrastructure. In1992, a contract was awarded to Angus Hamiltonand James Doig to make recommendations regard-ing the coordinate referencing program for eachMaritime province [NSLUC 1995]. In March of1993 they delivered the Report of the Task Force onControl Surveys in the Maritime Provinces (seeHamilton and Doig [1999]).

LRIS continued to operate using provincialfunding until it was closed on March 31, 1994[Sebert 1999]. LRIS left a legacy in terms of thecoordinate referencing system it produced. In themost remote regions of the province, one can stilllocate NSCMs which have existed for over 40years. The NSCCS effort was so well executed thatit would delay the province’s effort to migrate toNAD83 for over a decade.

The original LRIS vision was to migrate to aland titles system through Phase 3 of the program andto move towards a system with guaranteedbound aries [LRIS 1977]. The Land Registration Actwas passed by the Nova Scotia legislature in 2001and came into effect in various counties betweenMarch 2003 and March 2005. The Act created a new

land titles system with the intent of eventually replacingthe existing traditional Registry of Deeds, which hasbeen in existence for over 250 years. ColchesterCounty was the first to implement the system in NovaScotia, followed by Antigonish, Cumberland andPictou in December of 2003 [Hill 2015].

A property can be registered in the new landtitles system on a voluntary basis and must be regis-tered if it is sold or mortgaged. In partnership withthe Nova Scotia Barristers’ Society, the provinceprovides a limited guarantee of ownership ofreg is tered properties. The province guarantees title(ownership) but not boundaries or extent (size).Equivalently, the province affirms that one owns theproperty rights to a certain parcel of land, but cannotauthorize the location, size or location of boundaries.This role is left to a surveyor who can give apro fes sional opinion on these aspects [Hill 2015].

Technical Impact of theLRIS Effort

The LRIS changed the way that surveys wereconducted in Nova Scotia. LRIS greatly benefittedfrom being able to draw upon the Department ofSurveying Engineering that was formed at theUniversity of New Brunswick (UNB) in 1960. Theworld-class experts that the department recruitedprovided the expertise and knowledge necessary tosupport the creation of a coordinate referencing sys-tem for each Maritime province. Custom surveynetwork adjustment software (e.g., LEAP), as wellas specialized subroutines for reducing and process-ing survey observations, were developed either atUNB or internally.

Deficiencies in NAD27 would continue to beexposed with the development of new survey instru-ments and this resulted in an initiative to define a newdatum known as the North American Datum of 1983(NAD83). The expected unveiling of NAD83 did notcoincide with LRIS timelines for producing coordi-nates for the referencing system for each Maritimeprovince. It was desired to move to a geocentricdatum and to migrate to the metric system.

Reluctant to wait for the release of NAD83, theMaritimes leveraged the expertise of the SurveyingEngineering Department at UNB, GSD and LRISto develop a coordinate referencing system basedupon the Average Terrestrial System of 1977(ATS77) datum. This effort led to the publication ofcoordinates for 40 887 survey monuments in theMaritimes in 1979. The coordinates were calculatedin an adjustment that used positions and variance-covariance values from an October 1977 first-order

federal network adjustment as constraints [Gillis etal. 2000]. Issues with this adjustment would surfaceover the upcoming years. The problems were laterattributed to distance observations not beingprop er ly modelled. Maintenance adjustments forlocalized sections of the network would graduallyremove some of these errors [Flemming 2014].

In Nova Scotia, two 3°-wide zones weredefined to project coordinates using the ModifiedTransverse Mercator (MTM) Projection. Zone 4 iscentred on 61°30’ W and uses a false easting of4 500 000.000 m. Zone 5 is centred on 64°30’ Wand uses a false easting of 5 500 000.000 m. Whendeveloped, it was expected that the parameters usedto define the location of the ATS77 ellipsoid rela-tive to the centre of mass of the earth would beclose to those defined for NAD83. When NAD83was finalized, modifications to its reference frameand ellipsoid were introduced, causing a horizontalshift of approximately 4.5 m between ATS77 andNAD83 coordinates [Gillis et al. 2000].

The first realization of NAD was performed in1986 as part of the NAD83 redefinition and adjust-ment project. This became known asNAD83(1986) or NAD83(Original). In May of1989, a secondary regional network adjustment foreastern Canada was performed by the federal gov-ernment. The adjustment used approximately62 000 stations using the NAD83 datum and con-ventional observations. The computed coordinatesremoved most of the distortion in ATS77 but theachievable accuracies were still lim ited by theaccuracies of the original observations [Gillis et al.2000]. The set of coordinates generated, referred toas NAD83(1989), was the first major realization ofNAD83 in the Maritimes. A grid shift file namedGS7783.gsb was generated to transform betweenATS77 and NAD83(1989).

Emergence of the Nova Scotia CoordinateReferencing System

Upon closure of the LRIS, the Nova ScotiaGeomatics Centre (NSGC) assumed responsibility ofthe province’s coordinate referencing program underthe Land Information Management Services Divisionof the Department of Municipal Affairs. The programwould later move to the Department of ServiceNova Scotia and Municipal Relations in 2000. Therole of Coordinate Control Officer was established toprovide technical expertise for maintaining the

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NSCCS. A survey technologist role was alsoestab lished to support the Coordinate Control Officer.At its peak, the Surveys and Mapping Section ofLRIS had over 20 full-time human resources to sup-port it. It was not uncommon to have an additional 20students employed for summer programs.Maintenance of the NSCCS now resided with twopeople, while demand for maintaining the sys temwould only con tin ue to rise.

Prior to the LRIS being disbanded, Hamiltonand Doig [1993] made a number of recommenda-tions for the Maritime provinces to deliver upontheir coordinate referencing mandates, including:

1. Adopting a new GPS-based coordinate net-work, referred to as the Nova Scotia HighPrecision Network, which would be basedupon the Canadian Spatial Referencing System(CSRS)—this realization of NAD83 would bereferred to as NAD83(CSRS);

2. Operating the NSCCS and NSHPN in paralleluntil a formal transition to NAD83(CSRS) wasmade;

3. Creating cooperation amongst all users of theinfrastructure to maintain it;

4. Liaising with the user community on anongo ing basis;

5. Establishing, documenting and maintainingstandards and specifications for the NSCRS inconjunction with N.B. and P.E.I.;

6. Developing and maintaining the NSCRS withGPS;

7. Adopting the NSCRS through legislation;8. Training or recruiting a GPS specialist for the

long term;9. Compiling maps at a scale of 1:10 000 and

smaller using the UTM projection; and10. Compiling maps at a scale of 1:10 000 and

larger using the MTM projection.

To act upon the first recommendation, theMaritime provinces began discussions with GSD.They agreed to cooperatively establish 12 CanadianBase Network (CBN) reference frame points in theMaritimes. Additionally, the provinces decided tointegrate an additional 32 points throughout theMaritimes, forming the Maritime High PrecisionNetwork. Observations on this network took placein October 1994, with observation schedules care-fully planned. CBN points were observed for aminimum of three 24-hour sessions. Provincialsta tions were observed for a minimum of threeeight-hour sessions. Consequently, the additionalMaritime High Precision Network Points becametightly inte grated with the CSRS. This firstreal iza tion of the NAD83(CSRS) framework hadan average mon ument spacing of 60 to 70 km[Gillis et al. 2000].

Between 1995 and 1999, each of the Maritimeprovinces densified the Maritime High PrecisionNetwork within their own jurisdictions. InNova Scotia, a collaborative effort amongst surveyresources in the departments of Service NovaScotia and Municipal Relations, Transportation andNatural Resources would help execute the densifi-cation effort. By 2000, 153 Nova Scotia HighPrecision Network (NSHPN) points were estab-lished, with an average spacing of about 20 km (seeFigure 2). This system became known as the NovaScotia Coordinate Referencing System (NSCRS).The cost of this effort was approximately $750,000[NSLUC 1995]. In 2001, an active GPS station(HLFX) was installed at the Bedford Institute ofOceanography to assist in realizing more accurateversions of NAD83(CSRS) through the CanadianActive Control System (CACS).

Similar to the EDM Calibration Baselineini tia tive, a cooperative program between GSD andthe province established a GPS Validation Networkfor testing the reliability and accuracy of GPSequipment and software. The GPS ValidationNetwork consists of seven NSCMs located in FollyMountain, Enfield, Musquodoboit Harbour,Montague Road, Mount Uniacke, McGrath andHalifax (on the EDM Calibration Baseline).

Almost all of the NSHPN points were alsopoints in the NSCCS reference frame. This wouldallow for the generation of a set of transformationparameters to be defined in a grid shift file betweenATS77 and NAD83(CSRS) that was namedNS778301.gsb. It also reduced costs by recyclingexisting NSCMs into the new reference frame. Theaccuracy of this transformation is as good as a fewcentimetres, but discrepancies as high as 1 to 2 mexist for portions of the network with remainingblunders and/or distortions.

The adoption and migration to NAD83(CSRS)would prove to be a major challenge for the next15 years in Nova Scotia. This was partially attrib-uted to the NSCCS reference frame creating anunrealistic expectation that survey monumentscould be installed and maintained with 1-kmspac ing across the province. The 20-km spacingof the NSHPN was not practical for survey pur-poses. Connecting a sur vey to the NSCRS oftenmeant long drives to occupy a NSHPN monu-ment. Surveyors were forced to decide betweenleaving expensive GPS equipment unattended inremote locations while conducting a survey andpaying someone to guard it.

Between 1995 and 2012, several reviews ofthe NSCRS would be conducted in an effort todefine a strategy to move forward:

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• A Coordinate Referencing Policy for theProvince of Nova Scotia [NSLUC 1995]

• Final Report for the Study of the OfficialAdoption of the NSCRS [Jaques Whitford 2002]

• A Spatial Referencing Policy for the Provinceof Nova Scotia [GeoNova 2006]

• Final Report: Nova Scotia CoordinateReferencing System (NSCRS) Future PolicyStrategy [Seely 2011]

In each report, many of the key recommenda-tions made by Hamilton and Doig [1993] resurface.Because of the complexity of the subject matter, theability to inspire change, particularly when signif-i cant funding is required, would be an ongoingchallenge. From 2000 onward, NSLSs would con-tinue to express discontent with their inability toaccess the new NSHPN and the decaying NSCCSnetwork. It was hoped to have NAD83(CSRS) real-ized through the NSCCS framework. Such a taskwould involve re-adjusting over 100 000 conven-tional observations used to estimate the ATS77coordinates of the NSCCS framework. It was esti-mated that this would take years to execute. Justlike the NAD83(1986) and NAD(1989) realiza-tions, there was no guarantee that the accuracy ofthe results would be suitable for GPS.

By 2011, Nova Scotia’s first Coordinate ControlOfficer and NSCRS Geomatics Technologist had

retired. These were the only resources in theprovin cial government with an intimate knowledgeof the coordinate referencing observation and coordi-nate databases. Over 30 years of knowledge pertain-ing to a critical piece of the province’s infrastructurewas gone, leav ing an irreplaceable void. Similar situ-ations had arisen in New Brunswick, Prince EdwardIsland and other provinces across Canada.

In 2012, the province filled the CoordinateControl Officer position. Stakeholder engagementsessions and technological reviews were conductedto examine ways to respond to user needs. A majorfinding from that process was that several technolo-gies could be embraced to modernize the NSCRSand to help address identified needs. Specifically,these technologies included:

a)Active Control Stations (ACSs)—by perma-nently installing GPS equipment on NSCMs,users could access the data and not have tophysically occupy a traditional NSCM tocon nect to the NSCRS;

b)Network real-time kinematic (NRTK) surveys—by permanently installing a network of ACSs,users could benefit from reduced dis tancedependent, GNSS, error sources, resulting inhigher accuracy over longer dis tances;

c)Cellular communications networks—byuti liz ing the extensive cellular networks in the

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Figure 2: NSHPN reference framework.

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province, users could benefit from accessingreal-time, GNSS positioning services;

d)Crowd sourcing applications—by developingan application to accept observation data fromNSCM occupations, NSLSs could contributeto the ongoing maintenance of the NSCRS.

At present, NSLSs are still predominantlycon ducting surveys in ATS77. A modernizationeffort was started in 2012 to embrace the abovetech nologies with an emphasis on developing asus tainable maintenance program. It is hoped thatthe modernized system will address accuracy andaccessibility needs of the surveying community andthat this will facilitate the migration to NAD83(CSRS).The new CGVD2013 will also be embraced as partof this initiative. Many of the recommendationsmade by Hamilton and Doig [1993] 20 years earlierare being acted upon. It is anticipat ed that by the endof 2015, 40 ACSs will be installed in Nova Scotia.This infrastructure will not only create more efficientsurvey methods, but will also provide an opportunityto implement a sustainable maintenance model. Adetailed discussion of the NSCRS modernizationeffort is the topic of a subsequent paper.

OutlookThe core competency for a coordinate referencing

advisor is expertise in geodetic engineering. InCanada, this specialization is now acquired at thepost-graduate level at only a handful of universities.At the University of New Brunswick, it is estimatedthat one student graduates with a specialization inGeodetic Engineering (Master’s degree) every twoyears. With a limited resource pool, strategicplan ning is required to ensure the successful and sus-tainable delivery of geodetic referencing initiativesnot only in Nova Scotia, but across Canada.

Embracing technology and new strategies tomore effectively deliver upon coordinate referenc-ing mandates is critical to ensuring programsuc cess. Fortunately, the increasing use of ACSs formachine automation in industries outside ofsur veying has heightened the awareness of spatialreferencing technologies and their value to societyin general. The growing demand for spatial dataalso provides some assurance that coordinate refer-encing programs will be adequately supported inthe future. Regardless of how easy GNSS makespositioning in the future, there will always be aneed to be able to return to his toric data sets thatused different coordinate referencing systems andto have a clear understanding of how the pastrelates to the present.

Summary

This document attempts to capture the evolutionof coordinate referencing in Nova Scotia for knowl-edge continuity. Like most provinces in Canada, thefoundation of Nova Scotia’s coordinate referencingsystem originates with initiatives led by the federalgovernment. The coordinate referencing system ofeach Maritime province was impacted by the tremen-dous vision of Willis Roberts, first by the AtlanticProvinces Surveying and Mapping Program and thenby the Land Registration and Information Service.

With the dissolution of LRIS in 1994, eachMaritime province assumed responsibility for pro vi-sioning a coordinate referencing program. Since thattime, Nova Scotia has been attempting to fullymigrate its survey work to the GPS-com p ati bleNAD83 datum. Despite the NSHPN having higheraccuracy coordinates than the NSCCS ne t work, thegreater accessibility of the NSCCS has perpetuatedits use. In order to facilitate the migration toNAD83(CSRS), improved accessibil i ty to theNSCRS reference frame would need to be addressed.

In 2012 an effort to modernize the NSCRSthrough ACSs was begun. The ACSs have provided anew gateway to the NSCRS and have helped toaddress the accessibility challenge that the NSHPNdid not address. Over time, it is hoped that the tech-nology will be embraced and the migration toNAD83(CSRS) will occur. Figure 3 summarizes themain coordinate referencing systems that have beenimplemented in Nova Scotia. Figure 4 sym bolizes thechanges that have occurred as rep resented by thechange in NSCM signs over the past several decades.

AcknowledgementsThis work could not have been completed

with out the input and cooperation of: Bert Seely,Manager of Geographic Information ServicesOperations (Retired), Department of Housing andMunicipal Affairs, Province of Nova Scotia; NormanHill, Registrar General, Service Nova Scotia,Province of Nova Scotia; Allen Flemming,Coordinate Control Officer (Retired), Department ofHousing and Municipal Affairs, Province of NovaScotia; Pierre Heroux, Head, Analysis andDevelopment Section, Canadian Geodetic Survey,Survey General Branch, Natural Resources Canada;Colin MacDonald, Director, Geographic InformationServices, Internal Services, Province of Nova Scotia;Pierre Gareau, Manager of GeoNova Program,Geographic Information Services, Internal Services,Province of Nova Scotia.

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References

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Bond, J. 2015. Enabling high precision position monitoringon Sable Island through the Nova Scotia CoordinateReferencing System. Proceedings of the Sable IslandConference 2015, May 2, 2015, Halifax, Nova Scotia.

Craymer, M. 2006. The evolution of NAD83 in Canada.Geomatica. 60(2): 151–164

Dept. of Lands and Forests. 1983. Report on status of NovaScotia coordinate system. Internal Report, Departmentof Lands and Forests, Province of Nova Scotia.

Flemming, A. 2014. Coordinate Control Officer (Retired),Department of Housing and Municipal Affairs,Province of Nova Scotia. Personal Communication.

GeoNova. 2006. A spatial referencing policy for theProvince of Nova Scotia. GeoNova ReferenceCoordinate System Policy Node, Service Nova Scotiaand Municipal Relations.

Gillis, D., A. Hamilton, R.J. Gaudet, J. Ramsay, B. Seely,S. Blackie, A. Flemming, C. Carlin, S. Bernard andL.G. LeBlanc. 2000. The selection and implementa-tion of a new spatial reference system for Canada’sMaritime provinces. Geomatica. 54(1): 25–41.

Hamilton, A., and J. Doig. 1993. Report of the Task Forceon Control Surveys in the Maritime provinces.

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Figure 3: Main coordinate referencing systems used in Nova Scotia.

Figure 4: Evolution of the Nova Scotia ControlMonument Sign from 1968 to 2015. Top left—circa1968; top right—circa 1979; bottom left—circa1996; bottom right—2015.

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Hill, N. 2015. Registrar General, Service Nova Scotia,Province of Nova Scotia. Personal communication.

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MS rec’d 15/10/02Revised MS rec’d 15/10/26

Authors

Jason Bond manages the coordinate referencingsystem for the Province of Nova Scotia. He has aspecialization in geodetic engineering with a focuson GNSS through master’s and doctoral degrees atthe University of New Brunswick (UNB). Jasonalso has a Diploma in Cadastral Surveys from UNBand is working towards obtaining a Nova ScotiaLand Surveyor designation.

William Robertson was the manager of theControl Survey Section of the Land RegistrationInformation Service (LRIS) established through theCouncil of Maritime Premiers. He has over 20years experience with the coordinate referencingprogram for the Maritimes. He has been directlyinvolved with several key projects, includingestab lishing the Primary Control networks forPrince Edward Island and Nova Scotia, theReadjustment of the Maritime Control Network tothe ATS77 datum, establishing survey control onSable Island, early implementation of GPS toestablish control on Sable Island and to establishsurvey control for the construction of the CobequidPass Highway. He was a licensed Land Surveyor inNew Brunswick and a member of the Associationof Professional Engineers in Prince Edward Islandand Nova Scotia. q

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