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In geoinformatics, there is a considerable demand for dealing with different layers given in different geodetic datums and map projections within the same project. In the majority of the software, the computations are completed on-the-fly using the open-source program PROJ. In recent years, the definition of national reference systems for a wide ra...
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... projected coordinates were then transformed into the local system of reference points using a two-dimensional similarity transformation. Parameters were estimated using an open-source project, GeoEasy (Siki, 2018) applying a traditional least-squares solution with ± 7 mm root mean square error (Table 1). The shift values correspond to the x and y coordinates of the centre point, while the scale factor comes from height correction. ...Context 2
... projected coordinates were then transformed into the local system of reference points using a two-dimensional similarity transformation. Parameters were estimated using an open-source project, GeoEasy (Siki, 2018) applying a traditional least-squares solution with ± 7 mm root mean square error (Table 1). The shift values correspond to the x and y coordinates of the centre point, while the scale factor comes from height correction. ...Citations
... Laborde (1928) a korábban vázolt 2. és 3. lépést egy komplex transzformációba összevonva hozta létre Madagaszkár térképi vetületét. A fentiektől eltérő megközelítést választva a ferdetengelyű hengervetület általános leírását Hotine (1947) adja meg, amelyet később Snyder (1979Snyder ( és 1987 Látható tehát, hogy ferdetengelyű szögtartó hengervetületeket a világon számos országban alkalmaznak, különféle, akár helyi mérnökgeodéziai feladatokra is (lásd: Takács-Siki 2021). Az EOV azonban egy tulajdonságában mind közül mégis egyedinek mondható. ...
The Uniform National Projection System of Hungary (EOV) was defined for official surveying and mapping applications in Hungary. Its technical details including formulas and defining parameters are described in a technical standard released in 1975. The article shows that one of the constant values (indicted as k1) relating to an equation of the conformal Gaussian spherical projection was miscalculated and published in the standard with a wrong value 1/k1 =1.003 110 008 3 instead of 1/k1 =1.003 110 007 693. As one of the consequences of the incorrect constant’s value, the grid coordinates calculated with the standard closed formulas of the projection deviate from their true position with an average 2.6 mm in terms of horizontal distance. It has been proven this error occurs in the coordinates of the national horizontal first order geodetic network. Due to the incorrect value of k1 the ellipsoidal latitude of projection centre is also changed. It is the case because the EOV applies a unique two-step projection procedure where the ellipsoidal latitude of projection centre not given as an initial parameter but can be calculated from the 0,0 grid coordinates using the inverse equations of the projection. Applying the Hotine Oblique Mercator variant B projection (used in EPSG to describe EOV) with the newly calculated ellipsoidal latitude of projection centre (ϕ0=47°08’39.81744527”) the EOV can be approximated within 0.013 mm in terms of differences between standard EOV and Hotine grid coordinates.
... This Collection includes 4 papers representing some of the latest pre-pandemic trends in the geospatial community. Luciani et al. (2021) present their contribution to the monitoring of environmental conditions using a FOSS4G-based workflow for satellite monitoring system of subalpine lakes implemented within the SIMILE project; Stoppe and Flenker (2021) present a unique and innovative application of FOSS4G tools, applying their principles to the case of designing and visualizing electronic printed circuit boards, facilitating smoother and more ubiquitous user experience; Takács and Siki (2021) look into the precision of local coordinate reference systems, required for even tighter integration of the GIS and surveying disciplines; Siki and Takács (2021) showcase the potential of free software-based solutions in the automatization of surveying by detecting and identifying control points for aerial photography and real-time building deformation monitoring. Together, these papers highlight issues that will probably remain high on the agenda of the FOSS4G community in the coming years, e.g., extending the capabilities and applications of free GIS tools, demand for even higher precision of location data, and automatic high precision monitoring of environmental conditions. ...
This is the foreword to the Special Issue in the Baltic Journal of Modern Computing, which includes the papers originally submitted to the Academic Track of the FOSS4G Europe 2020 conference. The conference was canceled due to the COVID-19 restrictions, but the Scientific Committee responsible for the Academic Track still managed to publish the Special Issue (available at https://www.bjmc.lu.lv/en/contents/vol-92021-no-1) as initially planned.
The Oblique Mercator (OM) has been the runt in the family of conformal coordinate projection where its particular attribute of arbitrary orientation has been largely ignored. It is proposed that the Oblique Mercator, as a conformal projection, is well-suited to bridge the gap between a conventional north-oriented projection and the family of engineering grids that are unit-scaled and arbitrarily oriented improve the management of coordinate reference systems (CRS) between GIS and CAD/BIM software that has been, and remains, a significant cause of inefficiency for engineering design and construction, and for plane surveying. Issues relating to the selection of an optimal set of HOM projection parameters are discussed, including a new method to transform an existing engineering grid into an optimised HOM grid.
