Georeferencing Legal Surveys in British Columbia: A Pro-active Approach

Transcription

1 Georeferencing Legal Surveys in British Columbia: A Pro-active Approach

2 Agenda Background What is georeferencing and why is it needed? Equipment required Georeferencing Standards present and proposed Positioning Bearing derivation Practical uses, costs, advantages and disadvantages Next Steps

3 What is georeferencing? To georeference the act of assigning locations to atoms of information The method of georeferencing must be: Unique, linking information to exactly one location Shared, so different users understand the meaning of a georeference Persistent through time, so today s georeferences are still meaningful tomorrow

4 Background to the ABCLS initiative Digital Survey Plan Project Informal request from Surveyor General Review by External Relations Committee CCOG resolution proposed national standards Opportunity for increased role of the survey profession Opportunity to utilize current training for the benefit of society

5 Why is it needed? Increased demands by all levels of government and the public for georeferenced data Online applications for interests in land Accurate depiction/analysis of interacting interests in land (e.g. environmental, archaeological, minerals, riparian areas) Be pro-active, not reactive Move at our own pace Reduce the call for a coordinate cadastre

6 Societal demands Municipal Georeferencing Bylaws Integrated Land & Resource Registry (ILRR) & LRDW Client use of GPS Georeferenced data collection by other professionals (such as biologists and archaeologists) Spatial Navigation Google Earth

7 Georeferencing has been around for a bit Georeferencing has its roots in the earliest times of surveying and mapping. All of the world s early explorers and mapmakers used it. David Thompson, for instance, determined latitudes and longitudes of all the North West Company Forts, waterways, trails, etc. and later produced his map of western Canada from that information.

8 Later examples The federal and provincial governments over the years set out numerous triangulation or trig stations and the Canadian Hydrographic Service also set numerous control points along the coast; all to assist with their mapping.

9 Later examples The location of gas and oil wells outside the Peace River Block has always been governed by a georeferenced location; a certain latitude and longitude based on the spacing requirements depending on whether it was oil or gas.

10 Later examples The surveys for the first gas and oil wells in northeastern B.C. were started from the trig stations set by the Provincial Government in the early 1950 s. These trig stations were capped posts and most had towers built over them to assist in observations between stations.

11 Later examples The TRIM project, started in the early 1980 s, had numerous control points set around the province. Some were simple like the rock post shown here set on the edge of Pants Lake, south of Teslin Lake. Each had UTM coordinates determined for its location.

12 Introduction of Integrated Survey Areas Integrated Survey Areas implemented in the mid to late 60s Concentrated primarily on urban areas All legal surveys in an ISA must be tied to existing ISA monuments This form of georeferencing was the first used by most Land Surveyors and is now a way of life for those Land Surveyors practicing in an ISA.

13 Introduction of Integrated Survey Areas There are numerous ISA s around the Province Approximately 70% of the population of British Columbia lives within an ISA Approximately 50% of the parcels in the province are within an ISA. Network of monuments means most ties could be done using conventional methods although satellite based systems are sometimes necessary or more practical

14 Equipment needed for georeferencing For conventional surveys, a total station or even a theodolite and tape would work well. Another method would be to use the Global Navigation Satellite System (GNSS), commonly known as GPS.

15 A different tool for some of us We all know how to use our existing equipment and so this presentation will not dwell on that. It will focus more on the use of GNSS. Approximately one-third of our members have had formal training in GNSS and a large number of others have had some training. For others, GNSS will be a new tool in their tool box.

16 Fundamentals of georeferencing Horizontal positioning of a point or points within the survey (e.g. latitude/longitude, northing/easting) Horizontal positioning of points referenced to a commonly accepted or mandated coordinate system/datum Orientation of the survey (e.g. UTM grid bearings) Elevations (applicable mostly to P&NG surveys)

17 Current georeferencing standards At present, the standards for georeferencing vary depending on the type of survey and methodology used Currently, georeferencing rules are established for: Surveys in Integrated Survey Areas Mineral Tenure Act surveys P&NG Act surveys Land Act surveys Also suggested in General Survey Requirements for any surveys using GNSS measurements

18 Section 22(1) reads Surveys located outside of integrated survey areas, that are tied to geodetic control monuments or where all or part of the local survey is completed using differential GPS including derivation of bearings, must, if practical, be georeferenced to the British Columbia geo-spatial reference or other control approved by the association.

19 Section 22 continues Unless otherwise stated, the estimated network horizontal accuracy under subsection (1) must be less than 2 metres. [Section 22(2)] Surveys outside of integrated survey areas, other than surveys under subsection (1), may be geo-referenced by autonomous GPS or superior positioning methods. [Section 22(3)]

20 Proposed amendment to Section 22 All legal surveys outside of Integrated Survey Areas must be georeferenced, with the exception of Explanatory Plans. Lists the methods which are appropriate Outlines the positional accuracy required Allows for exemption where justified

21 Georeferencing can be accomplished by Ties to existing Integrated Survey Area monuments. Ties to survey posts on previously georeferenced plans. Ties to existing geodetic control monuments or trig stations. Ties to Provincial, Federal or municipal Active Control Stations

22 Proposed amendment to Section 22 The ERC feels this will help simplify the Rule and make it more understandable In response to our earlier survey of the proposed Rules, one land surveyor stated: the current rules are a bit unclear and sometimes contradictory, and these changes should help alleviate those problems. Good job.

23 Land Act requirements Rule 129 Rule 129(1) states (in part): Surveys that are located outside of integrated survey areas must: (a) be georeferenced by autonomous GPS or superior positioning methods Options within this Rule also include ties to a prominent topographical or structural feature on 1:20,000 mapping, or ties to the nearest existing cadastral survey.

24 Land Act requirements Rule 129 Accuracy of georeferencing is left up to the Land Surveyor, with the positional accuracy ranging from: centimetres (if using high end GNSS) 1-3 metres (mapping grade code differential/satellite service GNSS) 5-10 metres (if using hand held GNSS) metres+ (if tying to topo features could be lots worse!)??? (if tying to existing cadastral surveys)

25 Proposed Rule change Rule 129 would be simplified to: Surveys that are located outside of integrated survey areas must be georeferenced in accordance with Section 22

26 Mineral Tenure Act surveys Rule 171 Rule 171 has been recently amended by Rule Change SR5-04 and is more complex as it deals with legacy claims and cell claims All legacy and cell claim surveys must be georeferenced to an accuracy of 0.5 metres or less Allows for exemptions from the Rule in certain conditions, but only insofar as the level of accuracy is concerned

27 CCOG Resolution on accuracies Canadian Council on Geomatics recommends the following accuracies: Urban Areas 5 centimetres Rural Areas 20 centimetres Remote Areas 1 metre

28 What we are suggesting In an online poll, the majority of those members responding felt they could achieve the following: Urban Areas (within ISA) 5 centimetres Urban Areas (non-isa) 10 centimetres Rural Areas 25 centimetres Remote/backcountry areas 1 metre

29 Example 0.05m 0.25m 1.00m 0.10m

30 Methods of georeferencing by GNSS Differential or real-time GNSS from a known location (e.g. control monument Differential GNSS from a BC or Canadian Active Control Station Differential or real-time GNSS from municipal active control (e.g. CRD, GVRD systems) Precise Point Positioning (PPP) service from NRCan Private GNSS control (may not be validated stations!!!)

31 BC Active Control Stations

32 Canadian Active Control/WCDA stations Victoria Beaver Cove Chilliwack Penticton Eliza Dome Holberg Nanoose Nootka Island Ucluelet Williams Lake Whistler Calgary

33 GVRD Active Control

34 CRD Active Control

35 For more information BCACS CACS GVRD CRD PPP Service

36 Deriving bearings current Rule Section 21 of the Rules gives a number of options: Stellar observations Solar observations (conditional) Geodetic control monuments GNSS derived baselines (>150m) Existing cadastral surveys (with some conditions) Other methods approved by the Association

37 Deriving bearings current Rule Section 21 of the Rules also goes into great detail regarding: Where grid bearings must be used Where astronomic bearings referred to a local meridian must be used Where bearings referred to a township meridian must be used How bearings must be derived on long right of way surveys

38 Deriving bearings proposed Rule Section 21 of the Rules would be simplified to read: All bearings shall be grid bearings referred to the central meridian of the UTM zone in which the survey is situated, with the exception of Explanatory Plans whose bearings shall be referenced to existing records.

39 Deriving bearings proposed Rule Guidelines for how to derive and control bearings would be moved to the Manual of Standard Practice Options to derive bearings could include: GNSS derived baselines GNSS or conventional observations to geodetic control points Star or sun shots with application of convergence Ties to previously georeferenced surveys on grid bearings

40 Where can GNSS be used by land surveyors? Control surveys for legal, engineering, and topographical surveys

41 Where can GNSS be used by land surveyors? Control surveys for air photo control

42 Where can GNSS be used by land surveyors? Surveys for oil and gas exploration and well site locations:

43 Where can GNSS be used by land surveyors? Multi-lot Development Control for large projects

44 Where can GNSS be used by land surveyors? Geoid Ellipsoid Transfer of Elevations

45 Where can GNSS be used by land surveyors? Treed Area Reduce conventional traversing Found post

46 Where can GNSS be used by land surveyors? Calculated boundary Georeferenced survey Calculated boundary Precise Evidence Searches

47 Advantages Allows for more precise and efficient searches for evidence, potentially saving time and money for our clients Helps maintain the overall survey fabric of the Province Faster updating of your in-house mapping database All bearings on one common origin instead of an infinite number Integration of information from other sources (e.g. mapping, digital orthophotos, handheld positions)

48 Disadvantages Initial outlay of money to acquire GNSS equipment Time and expense in training and becoming proficient Slightly higher cost of survey to the client in some cases (keeping in mind that using GNSS may also keep costs down!)

49 What does it cost?... Pairs of dual frequency receivers are available in the $40-50,000 range (RTK ready) 2 & 3 unit packages of single frequency receivers are now available for under $10,000! Two single frequency receivers flanking a dual frequency receiver on a test baseline in Nanaimo.

50 What does it cost?... The cost per job will vary depending on the staff, equipment, locations chosen for observations, etc. There will certainly be some equipment costs, survey time costs and processing time costs and there may be some training costs to factor in. As you get more experienced with the equipment, these costs will come down. Remember, sometimes a few hours of GNSS survey can save a day or more of conventional survey!

51 For more information The Overview, Backgrounder, and Cost/Benefit Analysis as sent out by the External Relations Committee with the proposed Rule changes on August 08, 2006 has some excellent reading. We suggest you all read them.

52 A quote from the Overview to modify the regulation of cadastral surveys to incorporate and recognize modern positioning technologies and to add, through the use of these modern technologies, the full and complete integration of all cadastral surveys into a common coordinate framework to improve the mapping and strength of British Columbia s cadastral fabric.

53 A quote from the Backgrounder the Association and its members must take a leading role in georeferencing our surveys to a level that is acceptable for the purposes required therein, as well as to a level that will provide added benefit to the public, and the survey community as a whole.

54 In summary Georeferencing is not necessarily GNSS. GNSS is just another tool to get you there.

55 In summary In order for the georeferencing Rules and procedures to be effective, they must be: Practical Useful Achievable Flexible Improvable Measurable

56 In summary We feel the Rule changes as proposed meet all these criteria, and urge all members to embrace them now and be leaders in georeferencing and GNSS technology.

57 Next steps We are reviewing the comments submitted by members to see where improvements should be made Working with the CPD committee to promote seminars on GNSS/GPS More hands-on training and testing by our members Information, information, information!

58 Thanks for your attention and Happy Georeferencing!