Proceedings of Research Works 1998

Proceedings of Research Works 1998

250 66 Zdiby 98, tel. 02/685 7375, fax: 02/685 7056, e-mail: odis@vugtk.anet.cz

*KOCÁB, Milan*
TRENDS OF DEVELOPMENT IN UPKEEPING DIGITAL CADASTRAL MAP BY MICROGEOS SYSTEM
Proceedings of Research Works 1998. - Roč.44. - Zdiby : VÚGTK, 1998. - S.13-17. - ISBN 80-85881-10-1

Summary:

The current form and functions of the MicroGEOS system for upkeeping digital cadastral map in the Czech Republic (CR). New requirements on the system. Cadastre, Internet. Transition to Windows NT operating system and ORACLE database environment. A new MicroStation. Designs for digital cadastral map updating.

1. Introduction

On the base of the Czech Office for Surveying, Mapping and Cadastre (Czech abbr. ČÚZK) decision dated 30.3.1995, Ref. No. 598/1995-23, the programming system MicroGEOS has been introduced as the obligatory one for upkeeping digital cadastral maps in CR. In last two years, i.e. in 1996 and 1997 this system was not being further developed because of the ČÚZK decision, it was being only maintained. Now the necessity of further development of the MicroGEOS system is being shown, for upkeeping digital maps including connected database files.

2. Main functions of the current operational MicroGEOS system

The current form of the MicroGEOS system for upkeeping cadastral maps was successively arising in the Research Institute of Geodesy, Topography and Cartography (VUGTK) at Zdiby on the MicroStation products platform. In the beginning the MicroGEOS was being developed only for upkeeping digital cadastral map (Czech abbr. DKM), from the initial 3.0 version to the current MicroStation 5.00 22 (95) version in DOS environment, later also as a tool for easy digital data acquisition. The work has continued utilizing the experience of classic analog cadastral map updating method using survey data involved in a survey sketch. It was necessary to analyse, create, program, and verify all functions of MicroGEOS system. These works were being realized within the frame of the project "Automated Information System of Geodesy and Cartography" (Czech abbr. AISGK), paid by the Department of Economy of CR, and later by ČÚZK. The current MicroGEOS 5.2.3 version still operates under DOS operating system as a program superstructure of the MicroStation 5.00.22 (95) version. The current system includes functions for easy providing the geodetic information file data, contingently other graphic data in digital form to authorized surveyors (persons producing survey sketches), furthermore functions for taking over the DKM, partially already processed (digitally processed survey sketch). The system also ensures new data files checking and reflection of all accepted changes to the DKM.

2.1 Reference Drawings

Drawing files used at cadastral offices are incorporated in the MicroGEOS system in the form of fixed and uniform address data structure. Every user can easily choose either an active or a reference drawing or graphic raster drawings, and he can create suitable combinations of drawings himself. The original cadastral map drawing is most frequently used as a reference one (for reading only), lest it should become to damage or destruction. A special drawing is created as processed survey sketches, marks of error spots if batch processed drawing checks are used, survey of detailed points numbers and drawing of soil valued ecological units. Sheet line system with identifiers enable to connect raster map files of the previous land cadastre, and if need be, also ZABAGED1 or ZABAGED2 data.

2.2 Databases

A group of problems that was necessary to be solved in VUGTK was the connection of database files of various sheet line systems, descriptive information files of the cadastre of real estate (Czech abbr. KN), and databases of new minor control points related to the graphic file of DKM. The current database of points enables input of points represented by ten-digit, so as twelve-digit numbers, and before reading them a duplicity of points is checked in the file being read, and the file is compared with the connected database. Created functions are able to check whether DKM drawing does not differ from the list of coordinates of detailed points stored in relational points database. The database functions are able to draw detailed points into a drawing and this one whenever in automatized way update (delete non-valid, supplement valid). The database outputs into a text file with point numbers and codes of quality characteristics of them stored in the database, enable every person processing survey sketches to handle with numbers and coordinates acquired at a cadastral office with distinction of accuracy class.

2.3 Upkeeping (updating) - maintenance of DKM

The MicroGEOS system fully supports technological process for upkeeping (updating) the DKM determined by related branch regulations. The change being processed through a survey sketch is stored in a special drawing assigned for survey sketches and has adjoined to new lines, texts and marks an attribute of a record number of detailed surveying of changes (Czech abbr. ZPMZ). Change processing respects the condition that all traverse points must lie on the fundamental grid of the MicroGEOS system, and the intersection of two lines must be calculated in coordinates, split into lines and also moved to the system grid. This operation is solved in an automated way with the own MicroGEOS function. The function for DKM maintenance (updating) will project (after coming changes in descriptive information file into legal force) new map elements labeled with ZPMZ number into an active DKM drawing and the non-valid drawing will be deleted.

2.4 Checks

During creation of the MicroGEOS system a special attention was devoted to the check system for testing DKM data files, so that data should be geometrically correct and have a uniform structure. It is possible to check whether any geometric error occurs, also a duplicity, special conditions (e.g. length out of allowed range), location of texts and symbols - all this in a batch form for the entire drawing or for its part only. The checks will find whether for every detailed point of DKM drawing exists the respective coordinate data in the detailed data database, and vice versa - whether all valid points in the database have connection to DKM lineament. A very effective check is the comparison of complexity and area between parcels represented in DKM drawing and the same parcels involved in the descriptive information file database of KN. Also extreme deviations are tested between calculations of parcel areas of survey information file (Czech abbr. SGI) and data of descriptive information file database. After all checks are finished, a record (protocol) about course and results of testing will be done. The system of checks is also solved in regard to obligatory technical regulations in such a way that the acquired SGI file should be correct in all aspects and could be included in the state system.

2.5 Data protection

In the current system the protection of data files is ensured through access rights to individual DKM drawings. Only a worker with the highest priority has the right to "open" the cadastral map as an active one, and thus make it possible to modification. The second level of access rights represents a possibility of information providing (representation), and realization of outputs from data files for needs of survey sketches elaborations, and also providing cadastral data. The lowest level of access rights to DKM files is the drawings examination only.

3. Further development of the MicroGEOS system

A perspective cadastral information system must take into account all leGISlative facts to protection and farming on agricultural parcels of land. It must be prepared for arising interest in complete information connected with land market development. From this point of view it is clear that the MicroGEOS, in order to fulfil these requirements, must pass over to the new operating system Windows NT, to faster and more reliable database system. It will thus make possible the system to be more open to public, and connection of it to Internet, solving the internal interconnection with related SW, and introducing a fast and easy way of updating graphic data files. These requirements to MicroGEOS system are contemporary arising with technical conditions of progress in the area of informatics, accessible in the given time period. The contemporary development of the Bentley MicroStation, designs and the current state in Internet development, and databases development give a real form of requirements fulfilment on MicroGEOS development.

3.1 Integration with Windows

The development of operating systems gives a possibility to the MicroGEOS system to pass over to the reliable, fast and verified Windows NT platform. The operational environment Windows NT for MicroGEOS and MicroStation will enable to use an extended support OLE ensuring a non-problem cooperation between various SW applications (legal regulations, economic works, organizational security), and furthermore between all Microsoft Office applications. New optimized user interface would involve features and behaviour of the Office 97, support of colour icons and field. Administrative operations (advices of delivery, invitations, advice notes) could be sent directly from the MicroGEOS environment by help of any post system complying with MAPI (Mail Application Program Interface) specifications, as e.g. the Microsoft Exchange.

3.2 New database environment of MicroGEOS system

The rate and reliability of database environment will be the main requirement of a new MicroGEOS system. After testing various databases in VUGTK in 1995, the database environment ORACLE 7 was designed for the KN information file updating and maintenance. In this database environment there was in VUGTK also programmed the basic horizontal control updating and maintenance including graphic information storing. Among advantages of this database for KN maintenance can be included the fact that the database changes are recorded on disk not before they are confirmed by a command (unfinished operation is not stored). A translational diary enables automatic changes recording in the KN database. Cadastral information shall create one data model consisting of graphic and non-graphic information. Contingent differences occurred by comparison of correspondence between common SPI and SGI data would be removed at once. The mutual interweaving of graphic and non-graphic data will act on user as a uniform information. This KN data integrity is watched through interconnection (relation) between individual model tables in such a way that no "white spots" would remain there. Procedures (triggers) perform these operations automatically and often have a close connection to reference integrity of adjoined graphic DKM file. The MicroStation is one of the first products that are able to interconnect a graphic information with external data stored in the relation ORACLE database. This database system will also by its substance enable further innovations in data protection, and consequently the full utilization of the remote data transfer system.

3.3 Cadastre in Internet

The basis of a cadastral information system must be a good access to data and their easy long distance communication. Information systems in CR use various kinds of data transfer (e.g. special information highways, metropolitan networks) for which the combination of current available communication network is used. Very often also telephone lines are incorporated in the communication system, and these lines are intended also for future. For the cadastre a fast communication within the system is necessary, but an important condition for cadastre assertion in the market system is a fast external accessibility of it. A significant communication channel that enables to raise queries to cadastre throughout the whole week without any visit at a cadastral office, can be the Internet. The Internet cadastre (like e.g. Internet banking) ensures cadastral data protection through an electronic key, reliable ciphering software and digital signatures. Compared to "hand" information issue, the information providing (presentation) via Internet is about hundred times cheaper. The current version of MicroStation offers many new functions that enable a rich direct communication between Internet participants. The WWW viewer allows to connect DKM data with other documents on Internet and enables e.g. to copy data in a simple way as in Windows. Due to MicroStation tools for publication on Web, it is possible to afford data in C6M, SVF, PN6, VRML or HTML formats for remote users by help of international WWW standards.

3.4 New possibilities of DKM upkeeping (updating)

A digital map gives to user a number of possibilities of its easy and fast utilization in comparison with the classical (analog) map. Also the updating procedure brings many facilitations but till now no way is ideal. Besides the current way of DKM updating, further possibilities are being therefore proposed, for instance:

To elaborate a change (survey sketch) in a special drawing in such a way, that duplicated elements should not be projected into DKM, and all non-duplicated map elements from DKM should be removed. Successively to transfer non-duplicated (new) elements from a special drawing for a given territory to DKM. The whole operation should be realized in one technological step.
To prepare the survey sketch in such a way, that it should involve information on both kinds of elements (detracting - negative ones, and adding - positive ones). Negative elements are pointed up with colour for users. The updating will be realized by addition of this set to the current DKM.
To ask through leGISlative way a private subject for elaborating a survey sketch. The MicroGEOS system will perform a correct local DKM separation in the extent needed for any person elaborating the survey sketch, will record this information and after performed updating this DKM part, the fragment will be removed from DKM and replaced by a new up-to-date fragment.

3.5 DKM as a large scale map of CR

The DKM upkeeping and maintenance in form of sets of individual cadastral districts is already now accompanied with troubles at borders of two or more cadastral districts. The MicroGEOS system should pass over to a system of continuous seamless DKM upkeeping. This higher dimension supposes a uniform and correct data in all DKM files, and therefore it is necessary to create also new check functions for mass checking cadastral districts. Together with development of KN digitization, these tools will be very desirable. That means to pass over to a new system when individual programs of the MicroGEOS system, till now connected with topical drawing of one cadastral district, will be able to work with various graphic DKM files in the frame of the entire CR. The logic issue should then be a continuous digital large scale map of the entire state territory, an analogy of the present state map series SMO-5.

4. Conclusion

Some developmental trends to further advancement of the MicroGEOS system were already designed in 1995, but their realization was not accepted by the system manager. In a new way also some further problems can be now solved, which are connected with development and enhancement of the system core, i.e. the MicroStation. Costs for realization of these intentions would not essentially exceed the present purpose-given means for science and research development in this branch. The main part of means for realization would be blocked only for purchase of HW and SW products, that can be for ČÚZK branch also provided, under convenient financial conditions, by the own branch scientific and research basis at Zdiby.

Naposledy aktualizováno: 23.7.1998
Dotazy a připomínky k této WWW stránce na Milan Talich, Alexandr Drbal.