Karol Bartoš

The Verification of Compatibility of Spatial Points

The verification of the compatibility of points of spatial networks forms a very important component of completion and extension of networks by new points required for accurate geodetic activities. Therefore, it is necessary to have a quality geodetic control. A quality geodetic control can be achieved not only by new and quality measurement of new points, but also fine connecting points of which a new geodetic control is being established must be available.

The Verification of Compatibility of Planimetric Points

The verification of compatibility of points in planimetric geodetic controls that are part of national, regional network structures, or individual local, purpose-built networks represents a very important component of all processes of complementing and expansion of networks by new points that are necessary for different geodetic activities, requiring reliable geodetic bases, i.e., points.

The Verification of Compatibility of Height Points

The compatibility of height points HL, i.e., a geometric height identity of horizontal tangent plane of height survey mark (Fig. 4.1) with height data h from a certain vertical datum S(h) defined relative to the geoid or quasigeoid by the relevant level surface of the field of gravity (tangential to the survey mark), is just as important for the correct and reliable performance of altimetric measurements and determination of heights of new points as requirements for positional compatibility of geodetic controls.

The Compatibility of 1D (Height) Points

In the issue of height compatibility of different types of vertical controls (levelling, trigonometric, GPS, etc.), only levelling point fields, respectively, networks, that are so far dominant not only for the vertical expression of points relative to the geoid, or quasigeoid, but also in terms of the technology and accuracy of height determination, will be considered.

The Compatibility of Geodetic Control

Every survey control point (horizontal and vertical) has a physical mark and assigned numerical data (coordinates and heights) from certain reference systems, which should be related to a survey mark of this point. So far as those determining attributes are in stochastic planimetric or altimetric identity, the point can be considered as compatible, otherwise if specified attributes of point are mutually in geometrical significantly different positions, it is an incompatible point.

The Compatibility of 2D (Planimetric) Points

Consider the position of points defined by coordinates C = [X, Y] in a specific planimetric system S(XY), which are properly monumented on the earth surface or objects. It is obvious that each point, as stated in Chap. 2, must be identified and defined by the following two fundamental components in terms of its functionality.

The Compatibility of 3D Spatial Points

By using the GNSS technology (GPS, GLONASS, …), spatial positions of points in 3D coordinate systems (WGS-84, ETRS-89, …) are determined. As required by their geodetic use, they may or may not be transformed into national planimetric or/and vertical coordinate systems. Afterward, also the quality (or stability) of determined points is assessed separately in them.

THE APPLICATION OF OPEN-SOURCE AND FREE PHOTOGRAMMETRIC SOFTWARE FOR THE PURPOSES OF CULTURAL HERITAGE DOCUMENTATION

Abstract The documentation of cultural heritage is an essential part of appropriate care of historical monuments, representing a part of our history. At present, it represents the current issue, for which considerable funds are being spent, as well as for the documentation of immovable historical monuments in a form of castle ruins, among the others. Non-contact surveying technologies - terrestrial laser scanning and digital photogrammetry belong to the most commonly used technologies, by which suitable documentation can be obtained, however their use may be very costly. In recent years, various types of software products and web services based on the SfM (or MVS) method and developed as open-source software, or as a freely available and free service, relying on the basic principles of photogrammetry and computer vision, have started to get into the spotlight. By using the services and software, acquired digital images of a given object can be processed into a point cloud, serving directly as a final output or as a basis for further processing. The aim of this paper, based on images of various objects of the Slanec castle ruins obtained by the DSLR Pentax K5, is to assess the suitability of different types of open-source and free software and free web services and their reliability in terms of surface reconstruction and photo-texture quality for the purposes of castle ruins documentation.