GIScience Theory Based Assessment of Spatial Disparity of Geodetic Control Points Location

Abstract

Geodetic networks provide a spatial reference framework for the positioning of any geographical feature in a common and consistent way. An even spatial distribution of geodetic control points assures good quality for subordinate surveys in mapping, cadaster, engineering activities, and many other land administration-oriented applications. We investigate the spatial pattern of geodetic control points based on GIScience theory, especially Tobler's Laws in Geography. The study makes contributions in both the research and application fields. By utilizing Average Nearest Neighbor, multi-distance spatial cluster analysis, and cluster and outlier analysis, it introduces the comprehensive methodology for ex post analysis of geodetic control points' spatial patterns as well as the quantification of geodetic networks' uniformity to regularly dense and regularly thinned. Moreover, it serves as a methodological resource and reference for the Head Office of Geodesy and Cartography, not only the maintenance, but also the further densification or modernization the geodetic network in Poland. Furthermore, the results give surveyors the ability to quickly assess the availability of geodetic points, as well as identify environmental obstacles that may hamper measurements. The results show that the base geodetic control points are evenly dispersed (one point over 50 sq. km), however they tend to cluster slightly in urbanized areas and forests (1.3 and 1.4 points per sq. km, respectively).Hence, the base geodetic control points (thereinafter refed as BGCPs) are of utmost importance for georeferencing of manuscripts of historical maps [11,18,19] or images from unmanned aerial vehicles [20].Geodetic control points should cover an area relatively evenly to enable accurate and cost-effective measurements [21][22][23]. Although there is a variety of studies considering the design and densification of geodetic control networks [16,24,25] as well as investigating the influence of topographic objects that hinder the visibility of the horizon, interfere with satellite signals, and, finally, affect the quality of geodetic control stations' positioning [26][27][28], a profound analysis of the spatial pattern of geodetic control points still requires investigation. The problem of geospatial distribution of geodetic control points was previously discussed in several publications [29][30][31]. However, these studies were concerned with the detail (third-order) of geodetic network point analyses in relatively small (less than 200 sq. km) rural areas. The results, related to surveying units and then grouped according to land use types, showed that geodetic control points are scattered with significantly visible groupings along roads, railways, and built-up areas. Moreover, the number and density of geodetic control points depend on the development of the area in question, and 35% to 50% depend on the land cover, mainly in locations of built-up areas, roads, and railways [30,31].The density of geodetic control points is specified by the National Map...

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