International Journal of Pure and Applied Mathematics

Transcription

1 Volume 118 No , ISSN: (printed version); ISSN: (on-line version) url: ijpam.eu Study on the Current Assessment of Cadastral Surveying Performance and a Plan for Its Standardization-With a Focus on the South Korean Practice in Cadastral Surveying Sung-Eon Hong Dept. of Land Management, Cheongju University 298 Daedeong-ro, Cheongwon-gu, Chungcheongbuk-do Republic of Korea hongsu2005@cju.ac.kr, Corresponding author* Phone: February 4, 2018 Abstract Background/Objectives: The purpose of this study is to ascertain the current assessment of cadastral surveying performance to improve the accuracy in assessing the performance in cadastral surveying of graphical map-based areas and digital map-based areas, and proceed from there to suggest a standard method and procedure for assessing performance. Methods/Statistical analysis: For the purpose of deriving a more objective standard for cadastral surveying performance assessment, I have made an analytical investigation into different types of performance assessments. Findings: Based on the analysis of the current assessment, I suggest a standard proposal for assessing the performance in graphical map-based areas and digital map-based areas, beginning at the stage of data research

2 Improvements/Applications: Using a detailed manual that is created through future trial applications and revision of the method proposed in this study will improve the accuracy in assessing the cadastral surveying performance. Key Words and Phrases:Cadastral surveying, Graphical map-based areas, Digital map-based areas, Performance assessment, Standardization. 1 Introduction Cadastral surveying is divided into graphical cadastral surveying and digital cadastral surveying. Graphical cadastral surveying pertains to marking and registering on maps such as cadastral map or forest map land boundaries. Digital cadastral surveying pertains to marking and registering land boundaries mathematically with coordinates, that is, making the boundary of each lot with coordinates on a scatter chart (X, Y), instead of graphically marking land boundaries. Currently, it is stipulated that cadastral surveying in graphical map-based areas and digital map-based areas (land boundary coordinate register areas) employs methods such as plane table surveying, electronic plane table surveying, theodolite surveying, electro-optical wave distance surveying, photogrammetry, and satellite surveying 1. The above cadastral surveying methods have been performed in cadastral surveying. There have been many changes to the surveying method, however, since computerization of the land register and computerization of the cadastral map were completed. Specifically, once computerization was completed, surveying is no longer done with paper-based maps. So, electronic plane table surveying and performance assessment dominate graphical map-based areas and digital map-based areas 2. Electronic plane table surveying refers to the system that has automated the previously manually performed surveying process with surveying file (CIF) or computer file (DXF). While computer controls a total station, performance assessment is operated right on the screen 3,4. Even though electronic plane table surveying, a computerized surveying method, has been adopted, the performance assessment in graphical map-based areas which surveys land lot boundaries still

3 proceeds by the field boundary-based method. Performance assessments grounded in the field boundary-based method runs the risk of being influenced by the surveyors subjective view, as various methods are applied according to site conditions. Minimizing these problems would need to specify a standardized procedure and method for assessing performance. Earlier studies on cadastral surveying performance assessment are divided into those on a plan to improve the accuracy of performance assessments through visualizing the cadastral surveying history data 5, those on a plan to improve the accuracy of performance assessments with GIS analysis and through adjusting current coordinates 6,7, those on efficient management of performance data through a cadastral surveying performance management system8, and those on establishing standard procedures for reasonable performance assessments of cadastral surveying 9,10.0 Those earlier studies have limitations in that one single method was used to suggest a plan to improve the accuracy of performance assessments. And those studies on establishing standard procedures have limitations in that their suggested improvement plans are restricted to graphical map-based areas. In this study, I suggest a standard procedure for a cadastral surveying performance assessment method which can comprise graphical map-based areas and digital map-based areas. 2 Methods for Assessing Cadastral Surveying Performance and Actual Cases 2.1 Graphical Map-Based Area With an aim to obtaining a more objective standard procedure for assessing cadastral surveying performance, I have categorized the actual cases of performance assessment currently being conducted in graphical map-based areas and made an analytical investigation into the different performance assessment methods, through cooperation from Korea Land and Geospatial InformatiX Corporation (LX). Regarding the types of performance assessment, they are divided broadly into performance assessment which uses control point (supplemental control point), performance assessment which

4 uses the field boundary-based method, and performance assessment which mixes control point and field boundary-based method Performance Assessment Using Control Point Performance assessment which uses supplemental control point is a method used in those graphic map-based areas of which nearby situations are well-suited to supplemental control point. In other words, it is a method that implements performance assessment when the results from a reconnaissance survey suit the current situation. Further performance assessment methods are through restoring or creating supplemental control points. They are used in areas where reconnaissance survey or performance assessment was first carried out by a supplemental control point or a survey has been undertaken after a lost supplemental control point was restored. Or, the method is about assessing performance by adding to or subtracting from the performance in the supplemental survey through creating supplemental control points and observing existing minor control points for plane table surveying to get them suited to the locations of minor control points for plane table surveying, in areas that reconnaissance survey and performance assessment were implemented. This is the method that installs supplemental control points and implements an on-site survey with an aim towards future accurate performance assessment, and is frequently used in areas without existing supplemental control points in figure 1. Fig. 1. A case in which performance was assessed through restoring or creating supplemental control points

5 2.1.2Performance Assessment Using Field Boundary- Based Method Performance assessment which adds to or subtracts from the performance in the supplemental survey may be considered as performance assessment by control points. Actually, however, it should be taken as field boundary-based method, as it involves acquiring current data first and then changing the performance in the supplemental survey according to its adequacy. As a method that is the most often used following the adoption of electronic plane table surveying, it is a method that assesses performance by surveying nearby situations with supplemental control points and adding to or subtracting from the performance in the supplemental survey. As another field boundary-based method, assessing performance with a boundary determined by a land survey project is about assessing performance by taking as the reference boundary line the boundary of the land lots which remain the same as when registered for a land survey project. Assessing performance with existing registered lines is concerned with a target area where the boundary relocation or surveying of land division has been carried out and is about assessing performance in its adjacent area by referencing the boundary line. Assessing performance by actual situations such as topography or geographic features is about first implementing a reconnaissance survey on the target site and the assessing performance by taking as reference boundary lines such topography or geographic features as nearby fence line or furrows. Figure 2 shows a case in which performance was assessed by adding to or subtracting from the performance in the supplemental survey and with existing registered lines. Fig. 2. A case in which performance was assessed by adding to or subtracting from the performance in supplemental survey and with existing registered lines

6 Areas in which performance is assessed by control points and areas in which performance is assessed with the field boundarybased method may exist independently of one another. Occasionally, however, some areas do have the two types of areas adjacent to one another. While control points and the performance of the field boundary-based method exist in the same space in such areas, they are separately applied in performance assessment. 2.2Digital Map-Based Area In contrast with cadastral surveying performance assessment in graphical map-based areas, cadastral surveying performance assessment in digital map-based areas show practically no difference among surveyors (within allowed margin of errors), as it involves determining the location of the boundary for a land lot after accurate control points are installed in different phases (cadastral triangulation point cadastral complementary triangulation point supplemental control point), setting up equipment at those control points, and accurately surveying the angles and distances. Nonetheless, as errors may occur in registering control points even in digital map-based areas change of locations can be caused due to the road works, performance assessment needs to follow after checking on such issues. Focusing as much on the actual cases involving digital mapbased areas as on performance assessment in graphic map-based areas, the current study investigates the cases that used existing control points, the cases that tap into the restoration of existing control points, and the cases in which minor control points were created for the purpose of suggesting a standard proposal for performance assessment. Digital map-based areas experience no difficulty in performance assessment, as they, unlike graphic map-based areas, have accurate existing control points and their coordinates. Even though existing control points are employed, however, performance is assessed by determining its adequacy after nearby situations are surveyed first, in order to ensure a stable performance assessment. In case existing control points are lost, the control points in the same area are often restored and employed. If a survey was conducted with supplemental control points and by creating minor control points, the survey was implemented by creating minor control points around the site. Even though the initially used control points were going

7 to be used, buildings or other structures made it impossible to collimate the land boundary. Figure 3 shows an actual case in which performance was assessed by restoring existing control points or creating minor control points. Fig. 3. Actual case in which performance was assessed by restoring existing control points or creating minor control points 3 A Plan to Standardize Cadastral Surveying Performance Assessments 3.1 Graphic Map-Based Area Preliminary data research is equally the most important phase in performance assessment in graphic map-based areas. Data research, which involves a preliminary survey of the characteristics involved in performance assessments in a target area, represents the most important phase designed to prevent errors from occurring in performance assessment. Data research should be able to completely ascertain the existence of data of the current situation, past surveying history and used reference points, and the status of control points and performance assessment method. As data research proceeds and on-site surveys and performance assessments are implemented, a common standard needs to be established in a broad context with a view to deriving standards for different types of performance assessment. Namely, we need a standard that is commonly applicable to all types of performance assessment. This study has examined the laws and precedents related to cadastral surveying performance assessments and reviewed the commonly suggested standard. To summarize what has been derived

8 from the review, we should use the survey methods and reference points used when registered to the cadaster, in assessing performance. This means that land lots with a survey history should use existing reference points, as long as notable errors arent discovered in performance assessments. In case there is no reference point, a similar nearby reference point may be used. If there is no similar reference point, a basic survey should be implemented at a nearby supplemental control point. I have drawn up a common standard that should be broadly applied in assessing performance. Based on the common standard, specific criteria for different types may be presented as follows. First, the surveyor implements a reconnaissance survey and then determines the type of performance assessment for the site. The survey of the practice in performance assessment classified the types as the case in which performance is assessed by control point, the case in which it is assessed by field boundary-based method, and the case in which performance assessment utilizes both control point and field boundary-based method (performance separation). Here, performance assessment by control point may be divided broadly into two types. Namely, they are the case it adds to or subtracts from the performance in the supplemental survey. The case in which it adds to or subtracts from the performance in the supplemental survey refers to the areas in which a detailed survey is conducted and performance can be assessed accordingly. Graphic map-based areas differ from digital map-based areas in terms of performance assessment by control point. Even if performance is assessed with a control point in graphic map-based areas, a reconnaissance survey is carried out first and then its adequacy to the actual situation is verified for the control point. This is why it is deemed as another type of performance assessment in graphic map-based areas. The case involving addition to or subtraction from the performance in the supplemental survey apparently has its performance assessed by a control point, for which the performance is added to or subtracted from depending on whether it is adequate to the control point in the field boundary-based method. Therefore, itd best be regarded as a type of field boundary-based method. The areas of performance separation result in different types according to its adequacy to the field boundary-based method, so the

9 blocks in the areas of performance separation need to be marked in different colors for the purpose of clearly detailing spatial scopes by type. Table 1 shows the standard (proposal) for cadastral surveying performance assessments in graphic map-based areas. 3.2 Digital Map-Based Area Digital map-based areas may incur errors with their existing performance and therefore require thoroughgoing preliminary data research for the target area. And this involves determining the status of reference points, areal peculiarities, etc. for the purpose of assessing performance. Just as for graphic map-based areas, a broadly common standard for performance assessment has been created for digital map-based areas. In other words, a common standard has been created for thoroughly checking the control points in target areas, using the contemporary control points as much as possible, and checking the adequacy of acquired current data. Land boundary coordinate register area, where surveys are accurately performed according to control points, needs a common standard for checking errors with existing performance. Based on actual surveys, specific assessment methods are defined as performance assessment by an existing control point, performance assessment by restoring an existing control point, and performance assessment by creating a minor control point. Performance assessment by an existing control point required an inspection of the performance at nearby supplemental control points including the existing control points. Also, it required an inspection of the adequacy of the acquired current data. Data could be acquired anew and inspected despite the presence of existing current data. Performance assessment by restoring an existing control point should be applied if the existing control point is lost. Its method consists in restoring by checking the performance at a nearby control point and by tapping into a registered superior control point. If restoring is not easy, a control point should be created by checking the performance at a nearby control point. Performance assessment through creating a minor control point is applicable when collimating the boundary is difficult due to influence from buildings or structures. A minor control point is installed and used following

10 the inspection of performance at nearby control points. Table 2 shows the standard (proposal) for cadastral surveying performance assessment in digital map-based areas. TABLE 1. Standard (proposal) for cadastral surveying performance assessment in graphic map-based areas

11 TABLE 2. Standard (proposal) for cadastral surveying performance assessment in digital map-based areas

12 4 Conclusion The purpose of this study is to ascertain the current assessment of cadastral surveying performance to improve the accuracy in assessing the performance in cadastral surveying of graphical mapbased areas and digital map-based areas, and proceed from there to suggest a standard method and procedure for assessing the performance. The research has derived the following achievements. To begin with, for the purpose of deriving a more objective standard for cadastral surveying performance assessments, I have formed an analytical investigation into different types of performance assessment which are widely conducted in graphic mapbased areas and digital map-based areas. For graphic map-based areas, the types of performance assessment are divided broadly into performance assessment which uses control point, performance assessment which uses field boundary based method, and performance assessment which mixes control point and field boundary-based method. For digital map-based areas, the study investigates the cases that used existing control points, the cases that utilize the

13 restoration of existing control points, and the cases in which minor control points were created. Based on the analysis of the actual situation, a standard proposal has been presented for cadastral surveying performance assessment in graphic map-based areas and digital map-based areas. The standard method for graphic map-based areas is specified in the order of specifics of preliminary data research, commonly applied standard, determining the type of current situation survey and performance assessment, performance assessment by control points, performance assessment by field boundary-based method, performance assessment by the mix of control points and field boundarybased method, and performance assessment for areas without survey history. The standard method for digital map-based areas is specified in the order of specifics of preliminary data research, commonly applied standard, performance assessment by an existing control point, performance assessment by restoring an existing control point, and performance assessment through creating a minor control point. Using a detailed manual that is created through future trial applications and revision of the method proposed in this study will improve the accuracy in assessing cadastral surveying performance. References [1] Cadastral Surveying Enforcement Regulations. [2] Hong SE. Comparing efficiency of numerical cadastral surveying using TS and RTK-GPS. Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography September, 15(3), p. 88. [3] Lee JH. A study on the cadastral surveying method by electronic plane table.thesis, Inha University [4] Korea Land and Geospatial Information Corporation(Spatial Information Research Institute). A study on improvement method of cadastral surveying by digital cadastral map [5] Lee SK, Hong SE. Visualization method of surveying history data to ensure effective decision on cadastral surveying results

14 Journal of The Korean Society of Cadastre December, 26(2), pp [6] Park WC, Kim KR. PAI(Position Accuracy Improvement) for the cadastral boundary determination. Journal of Cadastre and Land Informatix(Korea Land and Geospatial Information Corporation) June, 41(1), pp [7] Park WC, Kim KR, Ra YH. Study on the improvement of cadastral surveying accuracy by adjustment model of the present condition coordinates. Journal of The Korean Cadastre Information Association June, 13(1), pp [8] Kim YM, Choi SY, Park MH. A study on the improvement of cadastral surveying result management system. Journal of The Korean Society of Cadastre December, 25(2), pp [9] Hong SE, Lee YH, Kim CK. A study on the establishing standard process for the rational decision making of the cadastral surveying in graphical map based area. Journal of The Korean Society of Cadastre June, 27(1), pp [10] Korea Land and Geospatial Information Corporation.A study on the decision making of cadastral surveying result

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