The actual state of the geodetic and cartographic resources and legislation in Poland

3.1 National spatial reference system and reference frames

Polish joining the European Terrestrial Reference System and Frame was carried out by measuring 11 points by GPS in 1992 in the EUREF-POL92 campaign. In 1994–1995, another 360 points were measured for the POLREF network, which were then used as reference points for converting points of the state networks to the ETRF89. Today, according to the Polish regulations on the national spatial reference system, apart from the PL-ETRF2000 system, the PL-ETRF89 system is an applicable geodetic reference frame. The national spatial reference system in Poland consists of geodetic horizontal and vertical reference frames, coordinate systems, and projections [3]. The central point of access to the Polish part of infrastructure for spatial information in the European Community [4] is the service geoportal [5].

In the service geoportal, we can find information about the actual state of reference frames and networks. The horizontal reference frames designated as PL-ETRF2000 and PL-ETRF89 are the mathematical and physical implementation of the European Terrestrial Reference System ETRS89. The system currently in force is PL-ETRF2000 with the implementation of epoch 2011.00. The result of physical implementation of PL-ETRF2000 is the European Permanent Network (EPN) with precisely designated coordinates and changes in these coordinates with time. The transfer into the territory of Poland and maintenance of the PL-ETRF2000 geodetic reference frame is supported by the EUPOS Active Geodetic Network (ASG-EUPOS) [7]. With the current status of legislation in Poland, from 2 October 2022, fees for using the ASG-EUPOS system services have been abolished [8]. As a result, almost the entire country already covers six correction systems. In addition to ASG-EUPOS, there are also five non-governmental networks: Leica SmartNet [9], RTKNet [10], TPI NETpro [11], VRSNet [12], and NadowskiNET [13]. Progress in correction systems enables real time GNSS positioning based on data from up to 500 reference stations. The development of GNSS systems has contributed to a significant increase in the accuracy and reliability of positioning. It significantly shortened the initialization time of the mobile receiver (rover) and made it possible to perform measurements in places with difficult access to satellite signals, in the so-called city canyons (e.g., in the vicinity of tall buildings or trees).

Today geo-data has been developing in the following plane rectangular coordinate systems [3], marked by symbols: PL-LAEA, PL-LCC, PL-UTM, PL-1992, and PL-2000 (Table 2).

Polish vertical reference frames are marked by symbols PL-KRON86-NH and PL-EVRF2007-NH. The vertical reference frame PL-EVRF2007-NH is associated with the tide-gauge in Amsterdam and should only be used in new projects realized from 1 January, 2014. The vertical reference frame PL-KRON86-NH is associated with the tide-gauge in Kronstadt and can be used until the implementation of the PL-EVRF2007-NH frame throughout the country until 31 December, 2023. This is due to the changing regulations that amend the regulation on the state system of spatial references [14].

Consequently, actual spatial (vertical) products of the digital elevation model (DEM) and the digital surface model (DSM), in the service of geoportal, will ultimately be presented in new layers: NMT-PL-EVRF2007-NH and NMPT-PL-EVRF2007-NH. There are more interesting tools for updating and publishing spatial datasets in geoportal: LIDAR measurement data, surface visibility, visibility along the line, terrain profile, landmass volume to plane, and volume of embarkment/excavation.

3.2 Geodetic control network

As is known, the main geodetic control network consists of points of the horizontal and the vertical networks. The coordinates of the horizontal base geodetic control network points mainly are determined by GNSS surveying and the heights of the points are usually determined by geometric precise leveling.

The base fundamental geodetic horizontal control network are stations of the ASG-EUPOS reference network, which belong to the network of permanent EPN stations. The points of the base fundamental geodetic horizontal control network meet the criteria established by the subcommittee EUREF and provide an average density of 1 point per 20,000 km². The average error of the point’s position should not exceed 0.01 m and the error of the point’s height should not be greater than 0.02 m.

The role of the receiving segment (ground control) of the ASG-EUPOS system is to collect the observational data from GNSS satellites and transfer them in real time to the calculation center. The segment consists of GNSS reference stations evenly distributed over Poland and neighboring countries [7]. According to the EUPOS standard, during the construction of the receiving segment, the following assumptions were made:

1. the mean distance between stations is 70 km,

2. the existing EPN and IGS stations have been incorporated into the network of reference stations,

3. coordinates of the stations will be determined in the ETRS89 system and national systems,

4. only precise dual-frequency GNSS receivers have been used in the reference stations,

5. the locations of the reference stations were chosen to ensure convenient conditions for GNSS satellite observations.

Next to the ASG-EUPOS system, where the total number of stations incorporated into the system is approximately 130, there are roughly 400 Polish commercial reference stations. Reference stations are mostly located on public administration buildings of the province and district levels, research institutes, and education buildings. Real-time services and post-processing services are provided in all reference systems (Table 3).

Corrections from reference networks are available on a specified TCP/IP address and port where before receiving data it is necessary to enter a username and password. When the system recognizes the user, it will enable the requested corrections. In the case of network corrections with a username and password, a receiver must send an approximate position in NMEA format to calculate corrections valid for this area (where NMEA is an acronym for the National Marine Electronics Association in United States of America).

3.3 SDI

Polish (national) SDI, according to the Act on Spatial information infrastructure [2], is established, maintained and developed by 12 leading bodies. Each leading body coordinates the work and assures the implementation within the scope of a specified theme related to the 34 themes of the SDI.

The Surveyor General of Poland plays a key role in the implementation process of the Polish NSDI. The implementation body of the Surveyor General is the Head office of geodesy and cartography that prepares and submits the government programs regarding the execution of tasks in the field of NSDI. 15 of the 34 themes specified by the directive on INSPIRE are implemented by the Head office of geodesy and cartography.

Another important player is the Ministry of Environment being the active leader of the implementation measures with regard to environmental data themes. In the Ministry of Environment, 14 themes are coordinated by 10 other central offices.

Considerable financial resources are mostly spent on the construction and development of a geoportal [5], and the development of modern sets (databases) of large-scale map data (Figure 1).

Figure 1

View of main information about the NSDI in Poland [5].

In the context of creating and sharing geo-data (resources), the role of the “Portal PZGiK” system (mentioned in Section 1) is important. Portal PZGiK is a specific record of resources (resource materials), and includes [15] the name of the resource material; inventory identifier of the resource material; the date of acceptance of the material into the resource; identification of the application for surveying works or the contract designation; spatial location of the area to which the resource material relates; information about data format of the resource material; and information about the creator and information on access to the resource material. In the case of excluding geo-data from the resources, information about the archival category of the resource material; the signature and date of the protocol of excluding the materials from the resources; the date of excluding the material from the resources and the date of transferring the material to the national archives, or the date shredding of the non-archival materials are recorded.

Geo-data stored in Portal PZGiK are described in the metadata profile by identifier in accordance with the applicable regulations. A registration identifier is assigned to the materials accepted into the resources, and then these materials are provided with an official clause. The resource material registration identifier consists of four parts (separated by dots), of which the first is the letter C – in the case of the central geodetic and cartographic resource (central resource), W – in the case of the voivodeship geodetic and cartographic resources (regional/voivodship resources), P – in the case of a district geodetic and cartographic resources (district/powiat resources); the second is the abbreviation PL – in the case of the central geodetic and cartographic resources, TERYT database identifier of the territorial division unit of the country (voivodship, powiat or municipal), competent for the authority keeping the record of materials – in the case of voivodeship and powiat geodetic and cartographic resources; the third is a four-digit number representing the year the material was accepted into the resources; and the fourth is the next natural number in a given calendar year.

3.4 Large-scale map data

Large-scale map data are stored in theme databases and are obligatory components of the national spatial information system. Along with other spatial data, they together co-create three thematic groups of the Polish spatial information infrastructure [2]. The large-scale base map in Poland has been created from several data sources [1,15]:

1. a real estate cadaster database EGiB,

2. the GESUT geodetic database of utilities,

3. the PRG national database of boundaries and areas of territorial division,

4. the BDPOG national database of base (first order) geodetic control networks,

5. the BDSOG district’s databases of detailed (second order) geodetic control networks,

6. the BDOT500 sets of topographical objects which ensure the creation of databases in the standard 1:500–1:5,000 cartographic scales.

In a modern digital form, typical large-scale cartographic products are created by compiling collected sets of data or databases. This approach facilitates the collection, maintenance, distribution, and use of the SDI. By reducing duplication, facilitating integration, and also respecting user needs, integration of data can result in savings [16,17].

We know that there are many methods of producing large-scale map data [18], which lead to different qualities of databases or maps. Accuracy and estimation of accuracy of the geo-databases guarantee that national geodetic and cartographic resources meet the relevant quality standards [19,20]. Moreover, it is essential to ensure the transparency of relations between the map producers and users and for developing trust in SDI through accuracy [21,22].

We have some new legislation for the theme of the large-scale cartographic products base (base map), called “mapa zasadnicza” in Polish [16]. In the new technical standard was characterized the database of topographic objects (Polish abbrev. BDOT500). The BDOT500 database collects information on buildings not listed in the a real estate cadaster database as well as construction objects permanently connected with the building; structures; fences; communication; land development; sports and recreation; waters; and landforms.

The attributes common to all objects of the BDOT500 database are method of obtaining information about the object, date of admission to the national geodetic and cartographic resources, and number of the technical reports with an identification of the application for surveying works or the contract designation.

The following methods of obtaining information about the localization of objects of BDOT500 database are distinguished: direct measurement in relation to the reference network (O is used for letter’s mark); vectorization (D is used for letter’s mark); photogrammetric measurement (F is used for letter’s mark); direct measurement with reference to objects, which are characterizing details with good identification in the field (M is used for letter’s mark); another method of obtaining (I is used for letter’s mark); and undefined method of acquisition (X is used for letter’s mark). Moreover, with each object of the BDOT500 database can be associated information that defines the heights of characteristic points located on the elements of these objects.

In case of the geodetic database of utilities (Polish abbrev. GESUT), practically each object must be associated with information that defines the heights of characteristic points located on the elements of these objects [23]. The heights of the characteristic points of GESUT database objects are defined in the vertical reference frame PL-EVRF2007-NH. Whereas, the location of GESUT objects is determined in the PL-2000 plane rectangular coordinate system.

The geometric representation of GESUT objects, depending on their types, can be a point, a broken line, a set of lines (multiline), a polygon (multiangle), or a set of points (multipoint). The dimensions of the sections of GESUT objects (diameter, horizontal, and vertical dimensions) are given in millimeters.

In addition to the abovementioned methods of obtaining information about the location of objects (in the BDOT500 database), in case of the GESUT database, three additional methods are distinguished: measurement with a wire detector (A is used for letter’s mark); data obtained from the administrator of the utility (B is used for letter’s mark); and documentation prepared on the so-called coordination meeting (K is used for letter’s mark). The previously developed district’s GESUT databases and the national GESUT database will be adjusted as per the applicable Regulation [23] by 31 December, 2022.

Next important geo-dataset is a real estate cadaster database (Polish abbrev. EGiB). Information with the methods of obtaining information about the localization of objects of the EGiB database also has great importance. In the light of the applicable regulations [21,24], the attribute related to the source of data about the location of the border point is of key importance by specifying the point position error, which is of fundamental importance for the correctness and reliability of the database.

In defining the cadastral parcel their boundary points, in accordance with new specification must be characterized attribute the way of obtaining data about the border point (Polish abbrev. SPD).

The boundary point takes the value of the SPD attribute as “per specification” in the case of geodetic field measurements preceded by demarcation of real estate or resumption of boundary signs and designation of boundary points; geodetic photogrammetric measurements of border points, the location of which has been previously determined, as well as photogrammetric measurements of boundary marks visible on aerial photos or on an orthophoto map as a result of their signaling before taking photos; division of real estate or merger and division of real estate, and by approved land consolidation or replacement projects. The boundary point takes the value of the SPD attribute as “unspecified” in all other cases.

However, in case of information on the compliance with the accuracy standards of the boundary point (attribute with the Polish abbrev. ISD), ISD attribute takes the value as “satisfied” when specifying the location of the point in relation to the points of the horizontal reference network, with an accuracy of not less than 0.10 m. The boundary point takes the value of the ISD attribute as “not satisfied” in all other cases.

Exchange and sharing of geo-data (where EGiB, GESUT, and BDOT500 databases are of major importance) take place in electronic form using the services network and web portals (geoportals) with the use of the files in GML format. These files have been generated from ISO TC/211 UML class diagrams and which the Head Surveyor of the Country publishes as XML Schema Definition (XSD) application schemas in the interoperability repository [25].

Sharing of geo-data takes place in reference to the regulations issued on the computerization of activities entities performing public tasks [26].

3.5 International geospatial initiatives and INSPIRE

In author’s opinion, the important issues for the NSDI are data sources, information about services, and new publication of them. Because the NSDI is strongly dependent on pre-existing infrastructures, it is necessary to present some characteristics of these infrastructures in some other regions and countries.

Initiation for Global SDI was provided by GSDI association [27]. The global association was the networking organization of academic and research institutions, government agencies, commercial geomatics companies, and national and regional associations.

The GSDI Association in 2018 was wound up as a legal entity and was used as a financial resource to support the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM) [28]. UN-GGIM aims to address global challenges regarding the use of geospatial information, including the development agendas, and to serve as a body for global policymaking in the field of geospatial information management. The main purpose of UN-GGIM is to support the works of the global geospatial information stakeholders and assist in the coordination of relevant activities between the organizations. The current members of UN-GGIM are Geoscience and remote sensing society, International association of geodesy, International cartographic association, International federation of surveyors, and International geographical union.

International map industry association, International society for digital earth, International society of photogrammetry and remote sensing, International union of geodesy and geophysics, and the International hydrographic office and the urban and regional information systems association are observing members.

The multi-national geospatial societies organization includes representatives from all continents, which are integrated in the regional board for Africa, Asia and Pacific, South America, North America, and Europe.

In Europe, a major recent development has been the entering into force of the INSPIRE directive in May 2007, establishing an infrastructure for spatial information in Europe to support community environmental policies, and policies or activities which may have an impact on the environment. INSPIRE is based on the infrastructures for spatial information established and operated by the 28 Member States of the European Union (until 2019, the United Kingdom data displayed are from before Brexit).

The INSPIRE directive requires the commission to establish a community geo-portal and the Member States shall provide access to their infrastructures through the geo-portal as well as through any access points they themselves decide to operate. For territory of Member States of European Union to provide discovery and view services according to the INSPIRE Regulation on Network Services, a release of the INSPIRE geoportal was published for enhancing access to European spatial data [29]. The INSPIRE geoportal provides the means to search for spatial datasets and spatial data services of the officially registered discovery services of EU countries and some EFTA countries [30].

There is important the National Spatial Data Infrastructure (NSDI) of the United States of America, because US NSDI is a pioneering venture in the world-scale and is provided by the Federal geographic data committee (FGDC). FGDC is an interagency committee that promotes the coordinated development, use, sharing, and dissemination of geospatial data on a national basis [31].

In 2020, US geospatial platform (GeoPlatform, [32]), operating under the authority of the Geospatial Data Act of 2018, transformed to establish its primary role which will be to discover geospatial data assets with special emphasis as the authorized source for all the official National geospatial data assets (NGDAs). The GeoPlatform provides streamlined access to NGDAs, across data themes as guided by the FGDC, and reduces data duplication.

Big datasets are produced with the support of the geological survey from US (USGS). The USGS is the science agency for the US Department of the Interior and is important for partners and customers for its natural science expertise and its vast earth and biological data holdings [33].

On the other hand, the Open geospatial consortium (OGC) plays an important role in the business sector. The OGC is an international consortium of more than 500 businesses, government agencies, research organizations, and universities driven to make geospatial (location) information and services in FAIR strategy – “Findable, Accessible, Interoperable, and Reusable” [34].

The OGC activity for spatial data and their processing since 1994, what is evidence of the unique value which are collegial and efficient networking and standards producing organization. International and government organizations cooperate with the OGC both to advance the standards and to learn about them.

The leading standardization organization is the International organization for standardization (ISO). The ISO is an independent, non-governmental international organization with a membership of 167 national standard bodies.

The ISO Technical Committee 211 (ISO/TC211) has developed the ISO 19100 family of standards, named “Geographic information/Geomatics.” There is a catalogue of standards provided by the Committee ISO/TC 211 [35].

3.6 Normalization and technical standards for geo-data in Poland

In Poland, the organizational structure of the geo-data (spatial information infrastructure) was established by the transposition of the INSPIRE directive into Polish Law. Within the infrastructure, initiatives may be implemented creating regional, local, and thematic geo-portals on the condition of ensuring that they are inter-operational and in compliance with the Polish and INSPIRE implementing rules [17].

In accordance with the update of the geodetic and cartographic law [1], many of the geodetic and cartographic resources are available free of charge and without any restrictions on use [36]. Some geo-data are currently available for download as follows: digital elevation model (Polish abbrev. NMT); digital surface model (Polish abbrev. NMPT); LIDAR data; 3D building models; Orthophoto maps; data of geodetic control network points (Polish abbrev BDPOG and BDSOG); database of topographic objects; database of general geographical objects; national registry of boundaries (Polish abbrev. PRG), and national registry of geographic names.

In addition, through the integration services in most cases, data may be downloaded separately. There is land and building register database (EGiB) which allows its users to generate a land and building register map for any area of the country [37].

The utilities network databases (GESUT) contain information about the existing and designed utility lines and related infrastructure [38].

In the case of other data (topographic features) are collected in proper in BDOT500 database, which acquired its for make up a full composition of base map [39].

Much of the geo-data are shared from the Polish National Geoportal of SDI by the “Data download” section. Mostly NSDI data are distributed in Web map service (WMS) standard which complies with the specification of OGC standard. WMS standard (in version 1.3.0) and International Standard ISO 19128 are the same documents. This standard is applicable to pictorial presentation (renderings) of maps in a graphical format in accordance with the International organization for standardization and the Open geospatial consortium specifications [40,41].

As we know, the basic standardization document is a standard (the normative document), i.e., a non-legal act, but a document adopted by consensus and approved by an authorized organizational body [42].

In terms of “Geographic information,” we have ISO [43], regional standardization (CEN, European Committee for Standardization [44]) and national standardization (for example: German – Deutsches Institut für Normung, DIN [45] and Polish – Polski Komitet Normalizacyjny, PKN [46]).

The normative documents are a valuable source of definition of specialist terms and therefore they deserve attention services of the German institute for standardization (DIN).

There are DIN-TERM [47] database for the terms and definitions from standards, draft standards, and specifications in the following languages: German, English, French, and Polish and the information portal developed by the German–Chinese Joint Committee of Industry and Trade [48].

In Poland, the Technical Committee No. 297 for geographic information operates as part of the work of the standardization committee (PKN). It covers all issues related to the modeling and design of data resources in spatial information systems and geo-data flow between different users and systems.

Modern knowledge in this area is included in more ISO standards of the 19100 series, adopted as European standards, as well as in the nation’s standardization documents. For example, in the years 2014–2020, Head office of geodesy and cartography in Poland implemented the POWER project [49]. POWER task was carried out by providing an information and knowledge about geo-data for public administration and for people interested in the geographic information. In addition, from 2011, the e-Guide was available, including entries from Polish (PKN) normative documents [50].

In the world today, there are three groups of data sources for acquisition of geo-data. Geo-data can be produced by different techniques:

1. field surveying by using total station and GNSS for direct measurement from terrain surfaces and with the use of geo-radar and other apparatus for the measurement of underground features.

2. photogrammetry by using photogrammetric images and point clouds and photogrammetric instruments and applications.

3. cartographic digitization by using existing maps and survey notes.

In Poland, geo-data are produced by various methods [18], and in accordance with the Regulation [51] standards were set out for geodetic works involving the technology of positioning of topographic points (especially for the large-scale map data) using field measurements, photogrammetric surveying, and map digitizing (so-called cartographic surveying).

Field measurements and other methods of data acquisition should ensure adequate accuracy of geo-data points. The horizontal positioning were divided into three groups of accuracy:

1. the 1st accuracy group, with an error not greater than 0.10 m (i.e. the so-called “well-defined” points, inter alia: marks of boundary points, marks of control network points, buildings and engineering structures, including elements of utilities available for direct survey);

2. the 2nd accuracy group, with an error not greater than 0.30 m (inter alia: ground buildings and construction devices in the form of embankments, excavations, dikes, levees, ditches, canals, artificial lakes, hidden elements of public utilities and land development components, particularly parks, lawns, playgrounds and recreation, single trees, and sports fields);

3. the 3rd accuracy group, with an error not greater than 0.50 m (inter alia: contours of agricultural land and soil pits for the needs of soil classification, rivers, and lakes with natural boundary lines, forestry fields on forest areas, and national parks).

In case of elevation (height) surveying, accuracy should not be less than: 0.02 m – for pipes and sewage devices; 0.05 m – for objects and equipment of building and marked pickets in the field; 0.10 m – for earthworks, flexible or electromagnetically measured underground utilities network, and unmarked pickets in the field.

In accordance with new legislation (paragraph 3. in [51]), measurements for the large-scale map geo-data are made using the methods, techniques, and technologies that ensure the above accuracies and the fulfilment of the conditions for performing the surveying works (jobs). The choice of the “right way” used for meeting the conditions for taking measurements and ensuring the required accuracy rests with the head of geodetic jobs.