The usability of GNSS mass-market receivers for cadastral surveys considering RTK and NRTK techniques

Nowadays many positioning techniques and methods are applied to the cadastral surveys. Starting from last decade, GPS/GNSS positioning had become one of the most used methodology thanks to the rapid development of satellite-based positioning and to the appearance of GNSS mass-market receivers and antennas. Methods based on these instruments are more affordable than the conventional ones even if their use for precise positioning is not so intuitive. This study is aimed to evaluate the use of singlefrequency GPS/GNSS mass-market receivers for cadastral surveys, considering both single-base RealTime Kinematic(RTK) and Network Real-Time Kinematic(NRTK) methodologies. Furthermore, a particular tool for predicting and estimating the occurrence of false fix of the phase ambiguities has been considered, in order to improve the accuracy and precision of the solutions. Considering the single-base positioning, the research results showed the difference of a few centimetres between the reference coordinates and the estimated ones if the distance between master and rover is less than 3 km, while considering the network positioning and the Virtual Reference Station correction, the difference are about a couple of centimetres for East and North component, and about 5 cm for the Up.

Research on Data Sharing between AutoCAD and MapGIS in Cadastral Database Construction

In the Second Chinese Country Survey, MAPGIS (Map Geographic Information System) is widely used all over the country in the Cadastral Database Construction. There are plenty original data is saved in the AutoCAD (Auto Computer Aided Design) data format. Therefore it is important to find a way which can exchange and share the data between AutoCAD and MAPGIS effectively and efficiently. In order to use MapGIS cadastral management system building cadastral database, it researched the current transformation methods between data of MapGIS and AutoCAD, including analysis defects of ObjectARX technology, southern CASS conversion interface, DXF file conversion. Combining the characteristics of MAPSUV data and southern CASS data, it found a data conversion method through the DWGdirectX control. This method actually read and wrote files provided by the library of MAPSUV and AutoCAD. This way avoids exchange process which can better transform the southern CASS DWG file containing graphics and attributes information to the SUV. The example which showed how DWG file transformed into SUV file. It improves the effectiveness and efficiency of conversion.

Underground space planning in Helsinki

This paper gives insight into the use of underground space in Helsinki,Finland.The city has an underground master plan(UMP) for its whole municipal area,not only for certain parts of the city.Further,the decision-making history of the UMP is described step-by-step.Some examples of underground space use in other cities are also given.The focus of this paper is on the sustainability issues related to urban underground space use,including its contribution to an environmentally sustainable and aesthetically acceptable landscape,anticipated structural longevity and maintaining the opportunity for urban development by future generations.Underground planning enhances overall safety and economy efficiency.The need for underground space use in city areas has grown rapidly since the 21 st century;at the same time,the necessity to control construction work has also increased.The UMP of Helsinki reserves designated space for public and private utilities in various underground areas of bedrock over the long term.The plan also provides the framework for managing and controlling the city’s underground construction work and allows suitable locations to be allocated for underground facilities.Tampere,the third most populated city in Finland and the biggest inland city in the Nordic countries,is also a good example of a city that is taking steps to utilise underground resources.Oulu,the capital city of northern Finland,has also started to ‘go underground’.An example of the possibility to combine two cities by an 80-km subsea tunnel is also discussed.A new fixed link would generate huge potential for the capital areas of Finland and Estonia to become a real Helsinki-Tallinn twin city.

Cadastral在农村集体土地所有权权属调查中的应用

本文主要以农村集体土地所有权权属调查项目为例,着重论述了Cadastral软件在做此类项目的应用情况。通过实际验证可知:Cadastral软件在农村集体土地所有权权属调查项目中的作用是显而易见的,它不仅缩短了项目作业时间,而且大大节约了生产成本。最主要的是在项目实施过程中,减少了中后期检查和内业的工作量。使测绘成果可信可靠,完全满足规程和精度要求,具有非常强的可操作性。

Discussion on Application of 3S Technologies in Cadastral Surveying and Mapping

In order to explore the application of 3S technologies in modern urban cadastral surveying and mapping,we analyzed the equipment composition of the global positioning system,the advantages of GPS surveying and mapping technology,and the main functions of RS and GIS technologies.GPS technology can improve the accuracy of boundary points of surveying and mapping areas,thereby improving the efficiency of surveying and mapping work and the accuracy of surveying and mapping information;remote sensing surveying and mapping technology has a large observation range and observation space,and RS technology can be used to collect data in remote mountainous areas to reduce the cost of manpower and material resources in surveying and mapping work;and GIS technology provides important data support for land planning and ownership definition.3S technologies optimize and streamline the surveying and mapping process with their own advantages,making the cadastral surveying and mapping work more scientific and efficient.

Integration of GIS in the Development of an Environmental Cadastre Administrative System for the Environment Protection Agency Sierra Leone

The Environment Protection Agency Sierra Leone (EPA) is mandated by law to issue Environmental Impact Assessment license. Currently the agency achieves this mandate by issuing environmental licenses manually which always encountered lot of problems of accountability and transparency of the management of environmental licenses and assessment documentation. Client’s information and documentation is usually mixed up while carrying files from one point to the other or from one staff to another. Data on client are stored in a way which makes it difficult for the management to retrieve useful information on time. This paper explores these challenges faced by the manual system of issuing environmental licenses and infer solutions to the current challenges by integrating a Geographic Information Systems (GIS) to develop an Environmental Cadastre administrative System (ECAS) which establishes a web-based information repository database developed with open sources software (Java, PHP, MySQL, QGIS) that published revenues online and made the data available to stakeholders and/or the public to complete the cycle of accountability and transparency. The information is presented and downloadable in a comprehensible and user-friendly manner, which in turn improves monitoring and reporting, and increases effectiveness and accountability of the management of environmental licenses and assessment documentation. The findings show these challenges facing the manual system, the back and forth between EPA and the client in the EIA process, the difficulty in the searching a client record, the mixing up of Client’s information and documentation by carrying files from one point to the other, and the storage of data on client in a way which makes it difficult for the management to retrieve useful information on time, and lack of back up when data or information is lost. Problems encountered in the time-consuming nature of the manual retrieval of files and preparation of prompt and accurate reports make it become a difficult task to accomplish as data and information are difficult to retrieve or collect from various files. Based on these findings, this paper provides the possible solution to the above problems. An online Environmental Cadastre administrative System (ECAS) which establishes a web-based information repository database was designed to capture the full lifecycle of environmental licenses including all stages of monitoring, licenses and payments and seamlessly manage the environmental impact assessment (EIA) licenses.

Development of Large-Scale Land Information System (LIS) by Using Geographic Information System (GIS) and Field Surveying

Cadastral maps are an important component of land administration in most countries. In virtually all developed countries, the needs of computerized land and geographic information systems (LIS/GIS) has given urgent impetus to computerizing cadastral maps and creating digital cadastral data bases (DCDB). This process is creating many institutional, legal, technical and administrative problems. This desire to establish DCDBs is being given increased impetus due to a new range of enabling technologies such as satellite position fixing (GPS), improved spatial data collection techniques such as digital theodolites and “soft copy” photogrammetry, as well as a vast range of new information and communications technological tools, thus contributing to the advancement and keeping up with the great countries. This paper presents the problem of cadastral maps. The hitherto existing cadastre, consisting of paper maps and land registers, is now becoming insufficient. Its shortcomings force developments leading to its improvement. One of the ways is the creation of a Land Information System. A digital cadastral map is the main component of this system. The structure and information content of the map is presented, its differences from analogue maps are shown, and the process of map creation is described. A digital cadastral map can be the basis for additional thematic layers, successively converting it into a complex system for management of administrative units.

Applicability of Databases in the Real Estate Valuation Process in the Conditions of the Emerging Economy of the Republic of Moldova

The real estate valuation activity in the Republic of Moldova dates from 2002, with the adoption of Law No. 989 on Evaluation Activity. Nevertheless, the legislative and methodological framework is extremely limited. There are no national professional standards. Meanwhile, the situations that require real estate valuation are multiplying and diversifying. Therefore, the valuers apply the provisions of the International Valuation Standards (IVS) and of the European Valuation Standards (TEGoVA) adapting them to the national realities by virtue of their knowledge and experience. Information stored in databases plays an important role in the real estate valuation process. In this paper, the authors analyse the content of existing databases in the Republic of Moldova (the databases of normative documents, the information system for the cadastre of real estate, the statistical databases, and specialized databases), the quality of the included information, as well as the applicability of that information in the real estate valuation process. The disadvantages, limitations and shortcomings of databases are highlighted, and measures are proposed to increase their usefulness.

Formalizing Land Administration through E-Governance Mechanism in Sri Lanka

This paper proposes a comprehensive and practical approach to implement a land administration act in Sri Lanka followed by setting up a Land Administration Commission (LAC), which is a separate entity to maintain a Land Administration Database Management System in support of the land information collected and maintained by stakeholders who deal with matters related to land and its decision-making under e-governance concept. Also, It describes the operations of the four core functions: land tenure, land valuation, land use, and land development in land administration under a single sustainable national land policy, underpinned by spatial information under the e-Governance mechanism. Further, the paper identifies the stakeholders and their main responsibilities in each of the four core functions with the current issues in sharing information across stakeholders. Finally, the paper describes setting up a Land administration entity thereby empowering the LAC and introduces spatial information layers at different resolution levels in a centralized land administration spatial database to keep track of all land transactions carried out by each stakeholder. This approach will enable the top-level decision-making authority (the central level) to manage all land-related activities under one platform to contribute towards the sustainable land development of the country. It is proposed to implement this approach as a pilot activity in the district of Colombo and expand it in the entire country gradually with its output.

Design and development of a web-based 3D cadastral visualisation prototype

Three-dimensional(3D)developments of land,such as complex high-rises,put enormous pressure on current land administration systems that have ad hoc approaches to 3D property management.These approaches are unable to support effective 3D storage,analysis and visualisation of property information.Effective visualisation is one of the essential components in realisation of a truly 3D cadastre.Currently,several 3D visualisation applications and cadastral prototypes have been developed around the world.However,they do not effectively represent ownership information in 3D because they have not been developed based on 3D cadastral visualisation requirements.After candidate 3D visualisation solutions were compared with user-derived visualisation criteria,a web-based 3D visualisation prototype was designed and developed.The functionality,usability and efficiency of the prototype were evaluated by potential users involved in the registration and management of property.While there was a high level of enthusiasm for the features of the prototype,the results also suggest further directions for development of 3D cadastral visualisation.

Exploring the applications of 3D proximity analysis in a 3D digital cadastre

Increasing population in urban areas and limitations of suitable lands for developing houses and urban infrastructure have led to the vertical development in cities.However,these developments are managed by a cadastral system which is mainly two-dimensional and cannot efficiently represent Rights,Restrictions,and Responsibilities(RRRs)in complex scenarios.In fact,a three-dimensional cadastre is required for efficiently registering and representing RRRs.In this paper,a 3D proximity analysis was proposed and implemented to determine RRRs and associated easement rights in non-topology-based data structures.This method can be used to investigate the surrounding spaces of a subject apartment unit or storage in a high-rise.The performance of the developed method was evaluated in a large complex high-rise in Tehran,Iran.The results confirmed that the proposed method can correctly identify the neighbor spaces in complex scenarios.

Integration of cadastral survey data into building information models

Cadastral surveying plays an important role in defining legal boundaries of land and property.The current practice for recording cadastral survey data mainly relies on 2D digital or analog documents.This practice is efficient for simple land parcels but can be challenged in complex building developments.To address the issues stemmed from 2D methods of representing cadastral survey data,3D spatial information models can be considered as a viable solution for managing cadastral survey data.Building Information Modeling(BIM)enables colsslaborative 3D management of the design,construction,and operation of buildings.There have been extensive studies conducted to investigate the connectivity between BIM and 3D cadaster.Most of these studies focus on managing legal information,such as ownership boundaries and attributes,in BIM-based environments.However,there is limited investigation on how survey-ing measurements can be mapped into BIM.In this study,the proposed method for integrating the cadastral survey data into the BIM environment includes identifying cadastral survey requirements,using BIM entities relevant to cadastral survey data,enrichment of a BIM proto-type,and evaluation of the prototype.The major contribution of this study is to demonstrate the storage of cadastral survey data such as survey marks and traverse lines in the BIM environment.Therefore,this research contributes to the further enrichment of BIM with incorporating data elements related to cadastral surveying practices.It is confirmed that current BIM-based tools provide restricted capabilities for explicit management and visualiza-tion of cadastral survey data.This limitation can be addressed in the future enhancements of BIM in terms of supporting important elements for cadastral survey data.

Expeditious management plan towards digital earth

The breakthrough developments in geospatial technologies and the increasing availability of spatial data make geoinformation a business and a decisional element to the management.Hence,it is important to have a management plan to factor in practical and feasible data sources,in building geo applications.The authors of this paper are motivated by the fact that right data sources could outclass in-house resources in various application scenarios.This paper outlines pragmatic cases for the tangible benefits of the existing potential data and expeditious patterns for digital earth.This work also proposes‘good-enough’solutions based on the pragmatic cases,available literature,and the 3D city model developed that could be sufficient in contriving the objectives of the common public usage and open business models.To demonstrate this approach,the paper encapsulated the low-cost development of virtual 3D city model using publicly available cadastral data and web services.

Exposing the urban continuum:implications and crosscomparison from an interdisciplinary perspective

There is an increasing availability of geospatial data describing patterns of human settlement and population such as various global remote-sensing based built-up land layers,fine-grained census-based population estimates,and publicly available cadastral and building footprint data.This development constitutes new integrative modeling opportunities to characterize the continuum of urban,peri-urban,and rural settlements and populations.However,little research has been done regarding the agreement between such data products in measuring human presence which is measured by different proxy variables(i.e.presence of built-up structures derived from different remote sensors,census-derived population counts,or cadastral land parcels).In this work,we quantitatively evaluate and cross-compare the ability of such data to model the urban continuum,using a unique,integrated validation database of cadastral and building footprint data,U.S.census data,and three different versions of the Global Human Settlement Layer(GHSL)derived from remotely sensed data.We identify advantages and shortcomings of these data types across different geographic settings in the U.S.,which will inform future data users on implications of data accuracy and suitability for a given application,even in data-poor regions of the world.