applied sciences Article Three-Dimensional Thematic Map Imaging of the Yacht Port on the Example of the Polish National Sailing Centre Marina in Gda ´nsk Pawel S. Dabrowski 1 , Cezary Specht 1,* , Mariusz Specht 2 and Artur Makar 3 1 Department of Geodesy and Oceanography, Gdynia Maritime University, 81-347 Gdynia, Poland; [email protected] 2 Department of Transport and Logistics, Gdynia Maritime University, 81-225 Gdynia, Poland; [email protected] 3 Department of Navigation and Hydrography, Polish Naval Academy, 81-127 Gdynia, Poland; [email protected] * Correspondence: [email protected] Abstract: The theory of cartographic projections is a tool which can present the convex surface of the Earth on the plane. Of the many types of maps, thematic maps perform an important function due to the wide possibilities of adapting their content to current needs. The limitation of classic maps is their two-dimensional nature. In the era of rapidly growing methods of mass acquisition of spatial data, the use of flat images is often not enough to reveal the level of complexity of certain objects. In this case, it is necessary to use visualization in three-dimensional space. The motivation to conduct the study was the use of cartographic projections methods, spatial transformations, and the possibilities offered by thematic maps to create thematic three-dimensional map imaging (T3DMI). The authors presented a practical verification of the adopted methodology to create a T3DMI visualization of Citation: Dabrowski, P.S.; Specht, C.; Specht, M.; Makar, A. the marina of the National Sailing Centre of the Gda´nskUniversity of Physical Education and Sport Three-Dimensional Thematic Map (Poland). The profiled characteristics of the object were used to emphasize the key elements of its Imaging of the Yacht Port on the function. The results confirmed the increase in the interpretative capabilities of the T3DMI method, Example of the Polish National relative to classic two-dimensional maps. Additionally, the study suggested future research directions Sailing Centre Marina in Gda´nsk. of the presented solution. Appl. Sci. 2021, 11, 7016. https:// doi.org/10.3390/app11157016 Keywords: three-dimensional imaging; thematic map; T3DMI; data harmonization; laser scan- ning; bathymetry Academic Editor: Paraskevi Nomikou Received: 4 July 2021 Accepted: 27 July 2021 1. Introduction Published: 29 July 2021 The purpose of using cartographic projections and creating maps is to present a convex Publisher’s Note: MDPI stays neutral surface approximating to the shape of the Earth (sphere or rotational ellipsoid) on a flat with regard to jurisdictional claims in two-dimensional surface [1]. The mapping functions enable the transition from angular published maps and institutional affil- coordinates of longitude and latitude to orthogonal coordinates on the plane [2]. Attributes iations. containing selected spatial information such as the course of borders, height in the adopted reference system, or the manner of land use are assigned to the planar coordinates [3]. A key feature of cartographic mapping is the mutual assignment of points on the Earth’s surface and the map’s surface [4]. As a result, a unique assignment of each point on the surface of the original to exactly one point on the surface of the image is obtained [5]. An Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. inherent feature of all mapping is the occurrence of mapping distortions. Hence, when This article is an open access article creating maps, the available projections are analyzed and the mapping is carefully selected, distributed under the terms and which in turn represents the desired region of the Earth in the least disturbed manner [6,7]. conditions of the Creative Commons Maps, due to various content and purpose, are divided according to various criteria. Attribution (CC BY) license (https:// Thanks to mathematical properties, mappings dedicated to the needs of specific areas of creativecommons.org/licenses/by/ human activity are known, e.g., navigation [8,9], or land surveying [10]. In turn, in order to 4.0/). present local and global processes, thematic maps are created [11]. The catalog of thematic Appl. Sci. 2021, 11, 7016. https://doi.org/10.3390/app11157016 https://www.mdpi.com/journal/applsci Appl. Sci. 2021, 11, 7016 2 of 12 Maps, due to various content and purpose, are divided according to various criteria. Appl. Sci. 2021, 11, 7016 Thanks to mathematical properties, mappings dedicated to the needs of specific areas2 of 12 of human activity are known, e.g., navigation [8,9], or land surveying [10]. In turn, in order to present local and global processes, thematic maps are created [11]. The catalog of the- matic map applications is constantly growing alongside the development of technology mapand applicationshuman needs is [12]. constantly An important growing theoretical alongside aspect the development of creating ma ofps technology is spatial visual- and humanization needs semiotics [12]. [13]. An important Semantic, theoretical syntactic, aspectand pragmatic of creating components maps is spatial determine visualization how to semioticsbuild and [13 connect]. Semantic, cartographic syntactic, elements and pragmatic on the map components and their determine relationship how with to buildthe re- andcipient. connect Technological cartographic development elements on over the the map past and few their decades relationship has largely with eliminated the recipient. the Technologicaluse of classic paper development maps. Currently, over the pastthe standard few decades use of has maps largely is electronic eliminated imaging, the use often of classicavailable paper on-line maps. [14]. Currently, The first signals the standard of a diametrical use of maps change is in electronic cartography imaging, were noticed often available on-line [14]. The first signals of a diametrical change in cartography were noticed as early as the 1990s [15]. as early as the 1990s [15]. Rapid technological development observed in recent years is also reflected in meas- Rapid technological development observed in recent years is also reflected in measure- urement technologies used to obtain source data for creating maps. Particularly notewor- ment technologies used to obtain source data for creating maps. Particularly noteworthy thy are the measurement methods that implement mass data acquisition in a short time, are the measurement methods that implement mass data acquisition in a short time, such such as laser scanning [16], bathymetric surveys [17], satellite GNSS measurements [18] as laser scanning [16], bathymetric surveys [17], satellite GNSS measurements [18] or or photogrammetric flight missions by unmanned aerial vehicles [19]. The large amount photogrammetric flight missions by unmanned aerial vehicles [19]. The large amount of data collected during these measurement methods calls for generalization, e.g., in the of data collected during these measurement methods calls for generalization, e.g., in the form of three-dimensional models [20]. Nevertheless, even after applying cartographic form of three-dimensional models [20]. Nevertheless, even after applying cartographic generalization procedures, the presentation of all objects at once is a complex problem. generalization procedures, the presentation of all objects at once is a complex problem. This especially applies to areas with a high degree of urbanization, where significant in- This especially applies to areas with a high degree of urbanization, where significant in- frastructurefrastructure facilities facilities are are located located at at points points with with the the same same horizontal horizontal coordinates, coordinates, but but at at differentdifferent heights. heights. Generally,Generally, maps maps differ differ in in both both the the content content and and component component parts. parts. Simple Simple maps maps consist consist ofof several several elements, elements, while while more more complex complex maps maps (e.g., (e.g., topographical) topographical) contain contain more elements.more ele- Everyments. map Every is a setmap of strictlyis a set defined of strictly graphical defined elements. graphical Some elements. of the signs Some are of subordinated the signs are tosubordinated cartographic to rules cartographic and depict rules some and real depict world some objects. real Other world elements objects. of Other the map elements are not of cartographicthe map are and not arecartographic thus subject and to differentare thus rulessubject or to do different not represent rules anyor do real not life represent objects. Ref.any [ 21real] mentionslife objects. an [21] example mentions of the an mapexam titleple of and the legend. map title Those and legend. descriptive Those elements descrip- aretive controlled elements byare natural controlled language by natural rules, langua and theirge rules, location and on their the lo mapcation is controlledon the map by is aestheticcontrolled rules by ofaesthetic the map rules creator. of the Thematic map creato mapsr. Thematic belong to maps the group belong of to geographical the group of maps.geographical Friendly maps. [22] states Friendly that they[22] states are effective that they in discoveringare effective and in discovering exploring spatial and explor- data. Theing theme spatial is data. related The to thetheme chosen is related phenomena to the (e.g.,chosen economic, phenomena demographical (e.g., economic, or cultural). demo-