COMPARISON OF THE METHODS OF CAPTURING DATA CONCERNING PARCEL BOUNDARIES IN ASPECTS OF THEIR
ACCURACY AND RELIABILITY
*Piotr Benduch, M.Sc.
AGH University of Science and Technology Department of Geomatics
Cracow, Poland
e-mail: piotr.benduch@agh.edu.pl Agnieszka Pęska, M.Sc.
AGH University of Science and Technology Department of Geomatics
Cracow, Poland
e-mail: agnieszka.peska@agh.edu.pl Abstract
The problem of capturing data concerning parcel boundaries, which determine the spatial range of proprietorship is very important and has been up-to-date for many years. There is no doubt, that process of collecting such an important information should be performed in a way that ensures the highest possible accuracy and reliability. However, as it turns out, these two notions do not always go hand in hand.
In accordance with being in force law, it is permitted to reveal data concerning parcel boundaries obtained by direct, photogrammetric and cartometric methods in cadastre. The accuracy and reliability of these data are of course different. That is confirmed by materials derived from surveying documentation centres. On the base of the materials, analysis concerning errors of parcel corners location in selected cadastral units has been performed. The problem of the reliability of the revealed data collected by the above-mentioned methods has been analysed too.
Finally, it was found that despite the significant technological progress in the fields related to surveying and cartography, data concerning parcel boundaries revealed in cadastre, at the present time cannot be recognised as equally accurate. It is also very important to properly distinguish accuracy and reliability terms. We should be aware, that the high accuracy of data does not always indicate their high reliability.
Keywords: register of land and buildings, cadastral parcel, boundary, data capture.
Introduction
In recent decades, capture of spatial data on the boundaries of cadastral parcels has been carried out by different methods, pursuant to various legal regulations and according to the technical standards.
Technological advances in surveying-related fields of study contributed to a significant improvement in the quality of the collected spatial data. This was of great significance with respect to the tasks set for the contemporary cadastre. Unfortunately, despite the introduction of numerous amendments to the legislation, the requirement of equal accuracy of the revealed spatial data still failed to be met.
It is acceptable to use the cartometric, photogrammetric and direct methods for their capture.
The authors attempted to compare the above-mentioned methods of capturing data on the boundaries of parcels in terms of their accuracy and reliability. Basing on the materials from the national geodetic and cartographic documentation center database, analyses regarding the problem in question were performed. The focus was on the studies on the boundary point attributes. It was noted that the high accuracy of the data on the boundaries of cadastral parcels is not always synonymous with their high reliability.
* This paper is the result of research carried out within Dean’s Grant no. 15.11.150.403 in AGH University of Science and Technology, Cracow, Poland.
Cadastral parcel, boundary, boundary point
According to (REGULATION, 2001), a cadastral parcel is a continuous area of land situated within a single cadastral unit, legally homogeneous, separated from the surrounding by means of boundary lines. The definition of a parcel boundary did not appear until 31 December 2013, and it defined a boundary as part of a circuit of the cadastral parcel, in the form of a broken line or a section, common to two adjacent cadastral parcels or coinciding with the state border – in the case of cadastral parcels adjacent to this border (REGULATION, 2001). A boundary will always be the most important spatial attribute of a parcel, as it defines its shape and determines its surface area. This means that the course of boundaries should be determined in the most accurate and reliable manner.
Here, special attention should be paid to the concept of a boundary point. Determination of the proper course of boundaries of a plot is the same as the correct determination of the position of boundary points. This procedure can take place during surveying proceedings, such as determination of the course of boundaries, modernization of the cadastre, or real estate delimitation (PĘSKA, 2014). Determination of the course of boundaries is often preceded by other surveying works, such as the map for design purposes (BIEDA, HANUS, 2010b) or real estate subdivision (BIEDA, HANUS, 2010a).
A proper determination of the position of boundary points is undoubtedly more important in terms of the reliability of the data on the parcel boundaries than the technical activity itself, such as the measurement.
Boundary point attributes
In order to ensure the uniformity and consistency of the data collected in the real estate cadastre, UML (Unified Modeling Language) application diagrams were introduced, which were contained in Appendix 1 to (REGULATION, 2001). It should be considered controversial that such significant information was not presented in the proper content of the regulation. From these diagrams it follows that to every boundary point, in addition to the identifier and rectangular coordinates expressed in the current geodetic coordinate system 2000, the following attributes are assigned:
a) denotation of the boundary point in the source material,
b) data source on the boundary point position (the polish acronym: ZRD),
c) mean error of the boundary point position (the polish acronym: BPP) relative to the first-order geodetic control,
d) code of the boundary point marking (the polish acronym: STB), e) code of the boundary order (the polish acronym: RZG),
f) information whether the point belongs to the disputed boundary of the cadastral parcel, g) additional information.
Attributes a – f are not obligatory, and therefore it still is acceptable not to enter the information referred to in points a – f in the register of land and buildings.
From the point of view of the article, the most important of the boundary point attributes include the data source on the boundary point position - ZRD (Table 1) and the boundary point position error – BPP (Table 2).
Table 1. Data source on the boundary point position (ZRD).
Value Definition
1 Field surveys preceded by real estate delimitation, restoration of boundary markers, determination of boundary points or of their position in a different mode, including the one specified in §39 sections 1 and 2 of the Regulation (REGULATION, 2001).
2 Field surveys not preceded by real estate delimitation, restoration of boundary markers, determination of boundary points or of their position in a different mode.
3 Photogrammetric surveys of boundary points, the location of which has previously been determined as set out in §37 section 2 of the Regulation (REGULATION, 2001), as well as photogrammetric measurements of boundary markers visualized on aerial photographs or on a orthophotomap, as a result of their signaling before taking photographs.
4 Photogrammetric surveys not preceded by the determination of the course of the boundaries of cadastral parcels or signaling boundary markers before taking aerial photographs.
5 Approved projects of real estate subdivision or reparcelling and subdivision.
6 Approved projects of reparcelling or exchange of land.
7 Screen vectorization of the cadastral raster map using the results of field surveys (linear tie distances).
8 Screen vectorization of the cadastral raster map without using the results of field surveys (linear measurements).
9 Other than ZRD1 – ZRD8 data sources, including the results of findings and analyses referred to in §39 section 3 of the Regulation (REGULATION, 2001).
Source: (REGULATION, 2001).
Table 2. Mean error of the boundary point position (BPP) relative to the first-order geodetic control.
Value Definition 1 0,00 m – 0,10 m 2 0,11 m – 0,30 m 3 0,31 m – 0,60 m 4 0,61 m – 1,50 m 5 1,51 m – 3,00 m 6 above 3,00 m Source: (REGULATION, 2001).
Over the years, the presented values and definitions of the attributes ZRD and BPP have been going through various changes. The most important of them is that, as of 31 December 2013 (REGULATION, 2013), errors of the boundary point position are determined relative to the first-order geodetic control. Before that, there was a provision about the errors of boundary point positions being determined relative to a geodetic control, but without its further specification (REGULATION, 2001).
A significant change, which occurred on 11 January 2016 (REGULATION, 2016), is also a change in the definition of the ZRD attribute equal to 9.
There was a great variety of ways to define individual values of the attributes ZRD and BPP over the past four years. In fact, their comprehensive update was not carried out. Therefore, in the cadastral database, next to the individual attributes of the boundary points, the information should be included, according to which legal provision a given value was assigned to them. It can be argued that the attributes ZRD and BPP are a measure of the reliability of the entered information about the course of boundary lines. It is essential, therefore, to reliably assign appropriate values to the individual attributes.
The methods of capturing data on the parcel boundaries and the ZRD attribute
Taking into consideration (Table 1) and (REGULATION, 2001), it can be concluded that in order to capture data on the boundaries of parcels it is possible to use the cartometric, photogrammetric and direct methods. Basing on the ZRD attribute, it is possible to determine which method was used.
In this respect, it is worth taking advantage of the assumptions proposed by (BENDUCH, 2016):
ZRD = 1, 2, 5, 6, (9) direct method
ZRD = 3, 4, (9) photogrammetric method
ZRD = 7, 8, (9) cartometric method
Unfortunately, after the last amendment (REGULATION, 2016) entered into force, the assignment of the cartometric method to the value of the ZRD attribute equal to 9 is not obvious. It is necessary to carry out additional studies on the methods of capturing data on the boundary point position.
The study area – Maków Podhalański cadastral unit and Zawoja cadastral unit
The cadastral units, where the modernization of the register of land and buildings was carried out in recent years, were selected as the research area. The main objective of modernization process was to complete the missing data and to modify the existing data so that they meet the requirements specified in the applicable regulations (REGULATION, 2001).
Below, there is the information about the boundary points at the selected cadastral units located in the Sucha Beskidzka district (Małopolska province). The modernization of the register of land and buildings in the Maków Podhalański cadastral unit was completed in 2005, and in Zawoja cadastral unit in 2015. The captured data will form the basis for further research and analysis:
Table 3. ZRD and BPP attributes of the boundary points of parcels in the cadastral unit of Maków Podhalański.
lack 1 2 3 4 5 6 7 8 9 In total
lack 388 812 0 0 0 1 4 787 0 0 1992
1 9 46256 7 1 0 1050 0 20 0 0 47343
2 0 14 0 0 0 0 0 0 0 0 14
3 0 0 0 0 0 0 0 8 0 0 8
4 0 0 0 0 0 0 0 0 0 0 0
5 0 0 0 0 0 0 0 2 0 0 2
6 0 0 0 0 0 0 0 0 0 0 0
In total 397 47082 7 1 0 1051 4 817 0 0 49359
Source: Own research studies based on the documentation from the geodetic and cartographic documentation center database in Sucha Beskidzka.
BPPZRD
Table 4. ZRD and BPP attributes of the boundary points of parcels in the cadastral unit of Zawoja.
lack 1 2 3 4 5 6 7 8 9 In total
lack 3 0 0 0 0 0 0 0 0 0 3
1 0 84 0 4590 0 6 0 0 1 0 4681
2 0 11386 0 0 1 5573 1 0 0 88541 105502
3 0 0 0 0 0 0 0 0 0 0 0
4 0 0 0 0 0 0 0 0 177 0 177
5 0 0 0 0 537 0 0 0 140 0 677
6 0 0 0 0 0 0 0 0 0 0 0
In total 3 11470 0 4590 538 5579 1 0 318 88541 111040
Source: Own research studies based on the documentation from the geodetic and cartographic documentation center database in Sucha Beskidzka.
The choice of the cadastral units was not accidental. In Maków Podhalański, during the works related to the modernization, the data on the boundaries of parcels were captured primarily by the direct method. In contrast, in Zawoja cadastral unit, the materials captured using the photogrammetric method were the basis of the modernization. Simultaneously, the vast majority of the boundary points was assigned the ZRD attribute equal to 9. Before 11 January 2016, this value corresponded to the screen vectorization of the cartographic studies other than the cadastral map.
In the following parts of the article, the authors attempted to discuss and compare the different methods of capturing data on the boundaries of parcels in terms of their accuracy and reliability.
The cartometric method
The cartometric method involves the use of the existing cadastral maps. This is the cheapest and the fastest method. It was widely used during the converting of the spatial part of the land register survey into the digital form (HYCNER, 2004). It is based on two technologies: digitalization and scanning of the existing cadastral maps in order to obtain their digital images (raster model), which can be converted into a vector form. The second of the mentioned technologies was primarily used in modern surveying.
The rules for scanning and calibration of the existing cartographic materials were defined in (REGULATION, 2011). The regulation provides that the use of cartometric surveys aimed at determining the position of field details covered by the cadastral database can only occur when there are no materials prepared as a result of performing field surveys or photogrammetric measurements. Thus, it can be concluded that the applicable legislation indirectly defines the cartometric method as a second-rate one, in relation to the direct and photogrammetric methods.
The discussed method is commonly recognized as not a very accurate one. Poor data quality results from the fact that it is a secondary process, involving the conversion of the existing information into a different form. As it was stated in (BIEDA, JASIOŁEK, HANUS, 2011), the accuracy of determining the coordinates of the bend point of a parcel boundary can be calculated from the following formula:
m ± m + m + m (1)
where:
mP – error of the boundary point position, mWK – error of marking the element on the map, mT – error of map transformation,
mW – error of boundary vectorization.
During the modernization of the cadastre in Zawoja, completed in the fourth quarter of 2015, the cadastral maps at the scale of 1:2880 were used, among others. Taking into account the considerations set out in (HANUS, 2006), it can be stated that the error of the boundary point position defined on the basis of the existing cadastral maps is approximately 0.60 m.
The performed study demonstrates that the application of the cartometric method in the cadastral unit of Zawoja allowed to reach the accuracy of the position of boundary points between 1.51 m and 3.00 m (BPP = 5). The accuracy of fitting the raster had a decisive influence on the value of the error of boundary point position when using this method in the analyzed area. Often, due to the small number of ground control points, especially in the case of cadastral maps, it is not possible to achieve a satisfactory result.
The analysis of the information contained in (Table 4) demonstrated that out of 318 boundary points with the value of the ZRD attribute equal to 8, 177 boundary points received the BPP attribute equal to 4, and 140 points - the BPP attribute equal to 5. These figures are very likely. One
BPP ZRD
of the boundary points was assigned the value of the BPP attribute equal to 1 which, given the discussion so far, should be considered a mistake.
The figure below presents the current courses of the boundaries of the selected parcels in Zawoja cadastral unit (lines in red color) against a calibrated cadastral map at the scale of 1:2880.
The differences in the positions of the boundary bend points between the archival cartographic documentation and the modernized cadastral database are very important. In some cases, the linear deviation exceeds 3 meters. This proves that the data regarding parcel boundaries captured basing on the presented map only, would be both of very low accuracy and reliability.
Fig. 1. The current parcel boundaries against the calibrated cadastral map at the scale of 1:2880.
Source: The geodetic and cartographic documentation center in Sucha Beskidzka.
The photogrammetric method
The photogrammetric method involves capturing data on parcel boundaries basing on photogrammetric materials, in particular aerial photographs processed from the central projection onto the orthogonal projection, brought to a uniform scale (orthophotomap). Its application also requires carrying out a large number of field works, associated with, for example, establishing a network of control points, their signaling, identification of parcel boundaries and making photogrammetric flights, as well as appropriate processing of the results. The accuracy of the photogrammetric method compared to the direct method is generally considered to be lower (HYCNER, 2004).
In recent years, as part of the project “ZSIN - Construction of an Integrated System of Information on Real Estate - Stage I”, throughout the country, works related to the modernization of the cadastral database were carried out. In many cases, photogrammetric materials were used to capture data on parcel boundaries. It is possible pursuant to §37 section 1 (REGULATION, 2001), where it is provided that if the national geodetic and cartographic center database lacks in proper documentation, based on which it would be possible to determine the course of boundaries of parcels, or these data are unreliable, the data is captured as a result of the performed field surveys or photogrammetric measurements preceded by the determination of the course of boundaries. §37 section 2 (REGULATION, 2001) expands the possibilities of using photogrammetric materials in the works related to the register of land and buildings, allowing for the determination of the course of parcel boundaries based on aerial imaging, satellite imaging or an orthophotomap. It is required that these materials have a resolution ensuring the visualization of topographic details that may be relevant in determining the position of boundary points. This procedure allows to determine the course of boundaries without field inspection.
In accordance with the applicable technical standards (REGULATION, 2011), the measurement of field details by the photogrammetric method is performed on a terrain model created from aerial photographs, for which orientation elements are determined in the process of aerial triangulation.
The technology of photogrammetric digital studies should be used. The use of laser scanning is also permitted, which may prove helpful in the future in the implementation of tasks related to the construction of a 3D cadastre. §44 (REGULATION, 2011) provides that photogrammetric measurements should be verified and completed by comparing the content of aerial photos with
the terrain, and carrying out the necessary topographic detailed field measurements. In relation to the capturing of the data on parcel boundaries, these activities are primarily aimed at verifying the correctness of the performed identification of the field details covered by the photogrammetric measurement, and completing the missing data on the boundary bend points, which were not available for the measurement in part or in whole. The most common reasons are trees or buildings.
This is a great limitation of the photogrammetric method, as mentioned, inter alia, in (BEDNARCZYK et al., 2015), where attention was drawn to the varying degrees of usefulness of the orthophotomap in the process of determining the boundaries of parcels, depending on the time of year when the surveying missions were performed.
Figure 2 illustrates a fragment of the orthophotomap from Zawoja cadastral unit, which formed the basis for the performed activities related to the determination of the course of boundaries of parcels and capturing data on their bend points.
Fig. 2. Boundaries of cadastral parcels against the orthophotomap used to determine their course.
Source: The geodetic and cartographic documentation center in Sucha Beskidzka.
Although the orthophotomap, whose fragment is illustrated in Fig. 2 meets the requirements of the necessary resolution, its usefulness for the determination of parcel boundaries in many cases is questionable. This is due to the trees and buildings which occur in the analyzed area. It should also be taken into account that the Sucha Beskidzka district is a mountainous area. The boundaries of cadastral parcels often run along slopes, which are not sufficiently visible on the orthophotomap.
Basing on the information contained in (Table 4), it can be concluded that in the cadastral unit of Zawoja, the data on the position of 4590 boundary points were captured using photogrammetric surveys, preceded by the determination of the boundaries (ZRD = 3). All of these points were assigned the BPP attribute equal to 1. According to the technical conditions for the modernization of the cadastre in Zawoja, issued by the District Office in Sucha Beskidzka, the photogrammetric survey was carried out on a terrain model created from the processed aerial or satellite photographs of the size of a pixel not exceeding 25 cm.
Both in the case of the measurement performed on the photogrammetric station, as well as in the case of the survey of the signaled boundary markers visualized on the orthophotomap, the result are the coordinates of a given field detail. So far, the literature has not provided any algorithm which would clearly define the accuracy of a boundary point position, determined by photogrammetric surveying. According to the explanations of the Central Office of Geodesy and Cartography regarding the compliance with §37 section 2 (REGULATION, 2001) in the context of public procurement carried out as part of the project “ZSIN - Construction of an Integrated System of Information on Real Estate - Stage I”, the accuracy of determining the position of a topographic point by the method of photogrammetric surveying should fall within the range:
‒ mXY≤ 0.40 m0,50 m - for the photographs in the scale of 1:13 000,
‒ mXY≤ 0.75 m0,90 m - for the photographs in the scale of 1:26 000.
Considering additional factors, such as the possibility to precisely identify the field details which are relevant to the determination of a boundary line, and the perception of the person performing the photogrammetric survey, the errors of boundary point position not exceeding 0.10 m relative to the first-order geodetic control (BPP = 1), are not entirely reliable. It is worth remembering as well that the orthophotomap is not a flawless document. It contains geometric errors, which are the consequence of the errors of the digital elevation model, exterior orientation errors and the errors resulting from the simplification of the application implementing the conversion process (TECHNICAL GUIDELINES, 2000).
Out of 538 boundary points with the ZRD attribute equal to 4, 537 of them were assigned the BPP attribute equal to 5. These were the points located on the boundary of the cadastral unit, mostly in forest areas, where the signaling of the boundary points was not possible. One of the boundary points with the value of the ZRD attribute equal to 4 was assigned the BPP attribute equal to 2. It was not, however, a point located on the border of the study area. The visibility and identification was not difficult in this case, and so the assumed accuracy of determining its position was higher.
In accordance with the technical conditions, during the works associated with the modernization of the cadastre in Zawoja, in order to capture data on the boundary point position, it was allowed to perform a cartometric survey on the orthophotomap created from aerial photographs of the terrain pixel size not exceeding 0.10 cm. This procedure was used in the case of 88,541 boundary points, which were assigned the ZRD attributes = 9 and BPP = 2. The surveyor's opinion was that the vectorization of the orthophotomap allowed to achieve the accuracy which met the requirements for a numerical description of boundaries (REGULATION, 2001), i.e. of not more than 0.30 m. relative to the first-order geodetic control. This means that the data captured in this way were used to calculate the surface areas of parcels and to enter them into the cadastral database. It is worth remembering that, pursuant to (ACT, 1989), the data contained in the real estate cadastre form the basis, for example, for imposing taxes and calculating benefits, as well as for the denotation of real estate in land and mortgage registers. The effects of such proceedings are therefore significant.
Unfortunately, possibilities to verify the actual accuracy of the boundary points determined in this way are very limited. This problem calls for broader research studies and analyses.
The direct method
The direct method is considered to be the best method of capturing data on parcel boundaries. Its very important advantage is the possibility to determine the actual course of the boundaries in the field (HYCNER, 2004). This method is based on the performance of field surveys. In recent years, the most popular measurements included tacheometric surveys (the polar method), however, satellite techniques RTK or RTN are becoming increasingly popular nowadays. When using the direct method, the data on parcel boundaries may also be captured from the documentation entered into the national geodetic and cartographic center database. This issue is regulated by §36 (REGULATION, 2001).
Specific rules for the performance of detailed topographic surveys were set out in (REGULATION, 2011). It is worth paying special attention to the ambiguity concerning the permissible accuracy of the boundary points position, referred to in the provisions on the register of land and buildings (REGULATION, 2001) and in technical standards (REGULATION, 2011). Pursuant to (REGULATION, 2001), the numerical description of boundaries is made using sets of boundary points whose position relative to the first-order geodetic control has been determined on the basis of topographic surveys with mean errors not exceeding 0.30 m. However, (REGULATION, 2011) states that the accuracy of the position of the topographic point which belongs to the first-group field detail is not less than 0.10 m relative to the closest points of the horizontal geodetic control and the measurement control.
Given the importance of the discussed issue, this problem should be unified.
Below, there are considerations regarding the most probable values of the BPP attribute of the boundary points whose position was determined using tacheometric measurement before and after the entry into force of (REGULATION, 2011):
Table 5. Predicted values of the BPP attribute of the boundary points whose position was determined using tacheometric measurement.
The measurement period
Error of the position of the first-group
accuracy field detail [m]
Error of the position
of the point of the measurement
control [m]
Error of the position
of the point of horizontal
third-order control
[m]
Error of the position of the boundary
point relative to the first-order
geodetic control [m]
Predicted value of the BPP
attribute
Before 22.12.2011 0,10 0,20 0,10 0,24 2
After 22.12.2011 0,10 0,10 0,10 0,17 2
Source: Own study based on (REGULATION, 2011), (REGULATION, 2012), (GUIDELINE, 1988).
The above considerations neglect the influence of the second-order geodetic control which, due to the assumed high accuracy, has no significant effect on the outcome of the analysis. The research confirms that the use of tacheometry to capture data on the boundaries of parcels does not form grounds for uncritical assignment of the BPP attribute value equal to 1, especially when the measurement was performed before (REGULATION, 2011) has entered into force. The total influence of the factors contained in (Table 5) is so significant that it is more likely to achieve the accuracy of the boundary point position between 0,110,30 m (BPP = 2). Nevertheless, these still are the values which meet the technical requirements set for the numerical description of boundaries.
In the case of the boundary points and markers, whose position is more and more frequently determined using GNSS satellite measurements based on the system of ASG-EUPOS reference stations, the BPP attribute takes the value of 1. It is assumed that the determination of the horizontal position of a field detail, using RTK surveying technique under standard measurement conditions, taking into account the adjustment data of the NAWGEO service, is carried out with a mean error not exceeding 0,03 0,05 m (ŁUCZYŃSKI, 2011), relative to the first-order horizontal geodetic control which, according to (REGULATION, 2012) is made up of ASG-EUPOS reference stations belonging to the network of contiguously operating reference stations EPN. Given the accuracy of modern surveying instruments, it can be concluded that in the case of a tacheometric survey performed basing on the points of a measurement control, whose coordinates were determined using satellite techniques, the resulting accuracy of the position of a field detail will fall within the range corresponding to the value of the BPP attribute equal to 1.
In the cadastral unit of Zawoja (Table 4), after the modernization of the register of land and buildings, 11,470 boundary points were assigned the ZRD attribute equal to 1, but only 84 of them were assigned the BPP attribute equal to 1. In the case of the remaining boundary points, the location of which was determined by the direct method, the position errors were determined at 0,110,30 m (BPP = 2). It should be noted, that even 40-years-old surveying data, which were entered into the documentation center database, were used. Therefore, the values of the BPP attribute assigned to these points are likely, as confirmed by the previously performed analyses.
A similar accuracy was defined for 5,573 boundary points, where the approved projects of real estate subdivision or reparcelling and subdivision were the data source on their position (ZRD = 5).
In Maków Podhalański cadastral unit (Table 3), the direct method was used for almost 98%
of the boundary points to capture data on their position. This is largely a consequence of the modernization of the register of land and buildings, completed in 2005. In contrast to the cadastral unit of Zawoja, in Maków Podhalański primarily archival documents were used.
The materials collected in the database, complemented by field surveys, which was preceded by determining the course of the boundaries, according to the surveyor, allowed to determine the position of 46,256 boundary points with the accuracy appropriate for the value of the BPP attribute = 1. The same position errors were assigned to the boundary points with the ZRD attribute
= 5. This does not mean, however, that a higher accuracy of the obtained results was assumed than in Zawoja cadastral unit. Prior to the amendment (REGULATION, 2001), which entered into force on 31 December 2013, the errors of boundary point position had been determined relative to the control, without its further specification. The technical requirements were therefore significantly less restrictive.
It is also worth noting that in the case of 812 boundary points in the cadastral unit of Maków Podhalański, which were assigned the ZRD attribute equal to 1, the values of the BPP attribute were not revealed. Unfortunately, the reasons could not be determined.
Conclusions
1. The cartometric method allowed for a fast conversion of the spatial part of the land register survey into the digital form. However, considering all of the discussed factors, it can not be expected that the accuracy, and consequently also the reliability, of the data on the parcel boundaries, captured based on the existing cartographic materials, was sufficient to carry out statutory tasks of the register of land and buildings. In time, these data should be replaced as a result of updates, or a comprehensive modernization of the real estate cadastre.
2. The photogrammetric method allows both to capture data about the position of parcel boundary points and to carry out the process of determining the course of boundaries. Its important limitation is inability to identify field details obscured by the canopies of trees and by elements of land development. Thus, it will not be suitable for highly urbanized or wooded areas. However, it may be used in lowland areas used for agricultural purposes.
3. The direct method still remains the one which, due to the possibility to determine boundaries in the field and the accuracy of the obtained results, is most suitable for the tasks related to capturing the data on the position of boundary points of parcels. Considering the nature of the problem, a very good solution, which is continuously gaining more and more popularity, are measurements using satellite techniques.
4. Depending on the method used, both the accuracy and reliability of the final results may vary significantly.
5. Carrying out topographic surveys which meet the technical standards should be regarded as a necessary, but certainly not a sufficient condition, so that the captured data on parcel boundaries could be considered reliable. It is necessary to reliably determine a course of the boundaries in question.
6. Carrying out a full and unambiguous assessment of the accuracy in terms of the position errors of the boundary points captured by the analyzed methods, for the purpose of determining the value of the BPP attribute is not performed. This attribute is usually determined conventionally, after examining the procedure which was used. Therefore, in order to obtain information on the reliability of the data on boundaries, it is necessary to analyze the source as well (the ZRD attribute).
7. The attributes BPP and ZRD of the boundary points contain important information. It is essential to assign appropriate values to them. The research has shown that this requirement, unfortunately, can not always be regarded as met.
8. Identical values of the attributes BPP and ZRD of the boundary points, depending on the legislation which is in force at the time of their entry into the cadastral database, have different definitions. The solution to this problem could be information concerning the legislation under which the individual values were assigned, provided in the form of a new boundary point attribute.
References
BEDNARCZYK, M., BIRYŁO, M., DAWIDOWICZ, A., DAWIDOWICZ, K., HLOTOV, V., KOWALCZYK, K., KWARTNIK-PRUC, A., PELC-MIECZKOWSKA, R., SIEJKA, Z., TOMASZEWSKI, D., WRÓBEL, A. 2015.
Modern Geodetic Techniques in Spatial Measurement. GIS Forum, Zagreb.
BENDUCH, P. 2016. The assessment of the influence of cadastral parcel boundary points location errors on the accuracy of analytical determination of their surface area. Geomatics and Environmental Engineering, Volume 10, Number 1, Kraków.
BIEDA, A., JASIOŁEK, J., HANUS, P. 2011. Wykorzystanie klasycznych map ewidencyjnych w podstawowych pracach geodezyjnych. Infrastructure and Ecology of Rural Areas, Number 4/2011, Kraków, pp. 193 – 202.
BIEDA, A., HANUS, P. 2010. Determination of real estate boundaries for the purposes of subdivision process. Geomatics and Environmental Engineering, Volume 4, Number 1, Kraków (BIEDA, HANUS, 2010a).
BIEDA, A., HANUS, P. 2010. Real estate boundaries on maps for projects. Geomatics and Environmental Engineering, Volume 4, Number 3, Kraków (BIEDA, HANUS, 2010b).
HANUS, P. 2006. Ocena przydatności dokumentacji byłego katastru austriackiego dla potrzeb prac geodezyjnych. Unpublished PhD thesis, Kraków.
HYCNER, R. 2004. Podstawy katastru. Wydawnictwa Naukowo – Dydaktyczne AGH, Kraków.
ŁUCZYŃSKI, R. 2011. Historyczne i współczesne technologie pomiarowe w aspekcie potrzeb katastru nieruchomości. Science session on occasion of 90th anniversary of Faculty of Geodesy and Cartography existing. Politechnika Warszawska, Warszawa.
PĘSKA, A. 2014. The Role of the Surveyor in Real Estate Delimitation Run during Administrative and Court Procedure. Geomatics and Environmental Engineering, Volume 8, Number 2, Kraków.
REGULATION of the Minister of Administration and Digitalization of 14 February 2012 on the geodetic, gravimetric and magnetic controls (Official Journal 2012, No. 0, item 352).
REGULATION of the Minister of Administration and Digitalization of 29 November 2013 amending the regulation on the register of land and buildings (Official Journal 2013, No. 0, item 1551).
REGULATION of the Minister of Administration and Digitalization of 6 November 2015 amending the regulation on the register of land and buildings (Official Journal 2015, No. 0, item 2109).
REGULATION of the Minister of Regional Development and Construction of 29 March 2001 on the register of land and buildings (Official Journal 2015, No. 0, item 542 - consolidated text, as amended).
REGULATION of the Minister of Internal Affairs and Administration of 9 November 2011 on the technical standards for the performance of horizontal and height measurements and processing as well as transferring results of these measurements to the National Geodetic and Cartographic Resource (Official Journal 2011, No. 263, item 1572).
TECHNICAL GUIDELINE O-1. The overall rules of performing surveying proceedings. Release IV, Warszawa, 1988.
THE ACT of 17 May 1989 Geodetic and Cartographic Law (Official Journal 2015, No. 0, item 520 – consolidated text, as amended).
THE RULES of preparing orthophotomaps in scale 1:10000. Technical guidelines. Central Office of Geodesy and Cartography, Warszawa, 2000.
