Generation of High Spatial Resolution Terrestrial Surface from Low Spatial Resolution Elevation Contour Maps via Hierarchical Computation of Median Elevation Regions

We proposed a simple yet effective morphological approach to convert a sparse Digital Elevation Model (DEM) to a dense Digital Elevation Model. The conversion is similar to that of the generation of high-resolution DEM from its low-resolution DEM. The approach involves the generation of median contours to achieve the purpose. It is a sequential step of the I) decomposition of the existing sparse Contour map into the maximum possible Threshold Elevation Region (TERs). II) Computing all possible non-negative and non-weighted Median Elevation Region (MER) hierarchically between the successive TER decomposed from a sparse contour map. III) Computing the gradient of all TER, and MER computed from previous steps would yield the predicted intermediate elevation contour at a higher spatial resolution. We presented this approach initially with some self-made synthetic data to show how the contour prediction works and then experimented with the available contour map of Washington, NH to justify its usefulness. This approach considers the geometric information of existing contours and interpolates the elevation contour at a new spatial region of a topographic surface until no elevation contours are necessary to generate. This novel approach is also very low-cost and robust as it uses elevation contours.Comment: 11 pages, 6 figures,1 table, 1 algorith

Raising Port Royal: A Geospatial Reconstruction of the 1692 City Through Integrated GIS and 3D Modeling

In 1692, the British port of Port Royal, Jamaica was largely lost to the sea after an earthquake shook the city down to the seabed, devastating the town and leaving the coastline of the peninsula permanently changed. Prior to its sinking, Port Royal was a town of some 6,500 people, a hub of shipping and commerce for the British West Indies, and a stronghold for British privateering in the Caribbean Sea. After the earthquake, the peninsula on which Port Royal had been positioned was dramatically shrunk, and the major residential and economic centers of the city were lost to the water. This project endeavors to apply the archaeological information collected during excavations of the submerged city to a larger geospatial analysis of the area prior to sinking. The first portion of this project looks at using historical cartographic and archival data, along with contemporary bathymetry and satellite images to reconstruct the coast of peninsula supporting Port Royal in ESRI’s ArcGIS software. The second portion of this project focuses on the buildings excavated between 1981-1990, creating 3D digital models of the five buildings within the reconstruction of the Port Royal shoreline, and integrating them into the GIS model for comparative analysis. This is, to the researcher’s knowledge, the first attempt to virtually reconstruct the structures of Port Royal based on archival and excavation data, and will allow for an interactive mechanism through which one can explore the structures of the excavated section of Port Royal in a scalable, geographically realistic way

Progress in the Reconstruction of Terrain Relief Before Extraction of Rock Materials—The Case of Liban Quarry, Poland

Open pit mining leads to irreversible changes in topographical relief, which makes a return to the original morphology virtually impossible. This is important for quarries that were part of former mining areas. This research presents an innovative approach to the reconstruction of the relief of anthropogenically transformed land on the example of Liban Quarry in Cracow, where operations began before 1873 to 1986. The basis for the reconstructed area was a Topographic Map of Poland with a scale 1:10,000 from 1997, from which a set of data was obtained to perform spatial analyses. The estimation was conducted using the ordinary kriging method, enabling a reconstruction of the morphology of the studied area and presenting it in the form of a hypsometric map and a digital elevation model. The correctness of the modelling was verified by cross-validation and a kriging standard deviation map (SDOK). These revealed low values of estimation errors in the places without contour lines on the base map. The comparison of the obtained maps and model with a Tactical Map of Poland with a scale 1:100,000 from 1934 indicated great similarities. The highest interpolation error value was recorded in the part of the pit where the di erence between the actual and reconstructed elevation was about 30mon average. In the exploited part, the SDOK did not exceed 0.52 m, and in the entire studied area, it reached a maximum of 0.56 m. The proposed approach fulfilled the assumptions of reconstruction, as the analysis revealed elements matching the historic relief in both forms of presentation of the topography of the quarry, on the obtained hypsometric map and on the tactical map. Our study is among the very few in the world concerning the application of geostatistics in the restoration of the relief of land transformed by open pit mining activities

Assembly and concept of a web-based GIS within the paleolimnological project CONTINENT (Lake Baikal, Russia)

Web-based Geographical Information Systems (GIS) are excellent tools within interdisciplinary and multi-national geoscience projects to exchange and visualize project data. The web-based GIS presented in this paper was designed for the paleolimnological project 'High-resolution CONTINENTal paleoclimate record in Lake Baikal' (CONTINENT) (Lake Baikal, Siberia, Russia) to allow the interactive handling of spatial data. The GIS database combines project data (core positions, sample positions, thematic maps) with auxiliary spatial data sets that were downloaded from freely available data sources on the world wide web. The reliability of the external data was evaluated and suitable new spatial datasets were processed according to the scientific questions of the project. GIS analysis of the data was used to assist studies on sediment provenance in Lake Baikal, or to help answer questions such as whether the visualization of present-day vegetation distribution and pollen distribution supports the conclusions derived from palynological analyses. The refined geodata are returned back to the scientific community by using online data publication portals. Data were made citeable by assigning persistent identifiers (DOI) and were published through the German National Library for Science and Technology (TIB Hannover, Hannover, Germany).Continen

Remote Sensing and Gravity interpretation ofNW Borneo: Integrated Basin Analysis on a GIS platform

Geographic Infonnation System (GIS) and remote sensing were applied and used to study the geological evolution of the sedimentary basin of NW Borneo. For this study, Landsat, SRTM, bathymetry and satellite derived gravity data were integrated, manipulated and visualized in a GIS platfonn by using the capabilities of the GIS software. The onshore region was studied by perfonning lineament interpretation using Landsat images and SRTM data, whereas in the offshore region bathymetry and gravity data were used to study the lithosphere of the region by gravity modelling. Lineament interpretation was done by using maps that were generated from the SRTM data (e.g. hillshade and contour maps) viewed concurrently with the Landsat images. Using the GIS tools, gravity and bathymetry data of offshore NW Borneo were extracted to study the lithosphere of this region. The area studied crosses the Dangerous Grounds, Sabah Trough and the Sabah Basin. The lineament trend was interpreted to be evolving !Tom W-E in southwestern Sarawak to NE-SW in the central region onto Sabah, and finally ending in anE-W trend at the northern tip of Sabah. This dynamic change in orientation, coupled with cross-cutting NW-SE lineaments, support the evidence ofmultiphase tectonic evolution that might result in the series of episodes of subduction and collisions during the geological history ofNW Borneo. For gravity interpretation, the principles of Airy isostasy were used together with the current tectonic model of NW Borneo to model the crust structure to agree. The resulting interpretation shows that the offshore region of NW Borneo is underlain by attenuated crust where the crust is thinnest beneath the Sabah Through. This thinned crust is buried underneath prograding sediments of the Sabah margin overlying accreationary prism fonned during subduction. The thin subducting crust is the remnant of the extended and attenuated continental rragment of Dangerous Grounds

Accuracy assessment in glacier change analysis

This thesis assesses the accuracy of digital elevation models (DEM) generated from contour lines and LiDAR points (Light Detection and Ranging) employing several interpolation methods at different resolutions. The study area is Jostefonn glacier that is situated in Sogn og Fjordane county, Norway. There are several ways to assess accuracy of DEMs including simple ways such as visual comparison and more sophisticated methods like relative and absolute comparison. Digital elevation models of the Jostefonn glacier were created from contour lines for years 1966 and 1993. LiDAR data from year 2011 was used as a reference data set. Of all the interpolation methods tested Natural Neighbours (NN) and Triangular Irregular Network (TIN) algorithms rendered the best results and proved to be superior to other interpolation methods. Several resolutions were tested (the cell size of 5 m, 10 m, 20 m and 50 m) and the best outcome was achieved by as small cell size as possible. The digital elevation models were compared to a reference data set outside the glacier area both on a cell-by-cell basis and extracting information at test points. Both methods rendered the same results that are presented in this thesis. Several techniques were employed to assess the accuracy of digital elevation models including visualization and statistical analysis. Visualization techniques included comparison of the original contour lines with those generated from DEMs. Root mean square error, mean absolute error and other accuracy measures were statistically analysed. The greatest elevation difference between the digital elevation model of interest and the reference data set was observed in the areas of a steep terrain. The steeper the terrain, the greater the observed error. The magnitude of the errors can be reduced by using a smaller cell size but that this is offset by a larger amount of data and increased data processing time.Popular science Glaciers are very sensitive indicators of climate change. The major cause of melting glaciers is global warming. This rapid rate of melting has serious negative impact on the earth causing flooding, leaving impact on flora and fauna, resulting in shortage of freshwater and hydroelectricity. The long-term monitoring of glaciers and the knowledge gained from it can help governments, environmental and water resource managers to make plans to cope with impacts of climate change. Results from glacier monitoring ought to be precise, showing the actual situation compared to the situation in the past as well as predicting possible glacier changes in the future. The aim of this thesis was to investigate how sensitive the results were to different methods used in glacier change detection focusing on the quality of Digital Elevation Models (DEMs). The study area of this thesis was the Jostefonn glacier situated in Sogn and Fjordane county, Norway. Digital elevation models were created from contour lines for years 1966 and 1993. LiDAR data from year 2011 was used as a reference data set. Several techniques were employed to estimate the accuracy of digital elevation models including visualization, statistical analysis, analysing the accuracy of digital elevation models for terrain on different slopes, comparison to a reference data set outside the glacier area that was considered to be stable and where no elevation change was expected. The original contour lines (1966 and 1993) were compared with the ones generated from the created terrain models (glacier area) as well as with the contour lines from the reference data set (outside the glacier area) by visualization techniques. Accuracy measures (Root Mean Square Error, Mean Absolute Error and others) were statistically analysed. Natural Neighbours and Triangular Irregular Network interpolators proved to be superior to other algorithms used to create the terrain models. The best outcome was achieved by using as small cell size as possible. 5 m resolution rendered the best results from the resolutions tested (5 m, 10 m, 20 m and 50 m). The greatest elevation differences were observed in the areas of a steep terrain. The steeper the terrain, the greater the elevation difference. The terracing effect was noticed in the digital elevation models due to the high density of elevation points on the contour lines and hardly any points between them. Useful information can be obtained by estimating accuracy of digital elevation models. The accuracy of terrain models determines the reliability of glacier change analysis and that is why the digital elevation model must represent the terrain as accurately as possible. The different methods used in this thesis rendered very similar results and that indicated that the results were reliable and the terrain models created with Natural Neighbours and Triangular Irregular Network interpolators (resolution of 5 m) can be employed in further glacier change analysis

GIS-based landscape design research

Landscape design research is important for cultivating spatial intelligence in landscape architecture. This study explores GIS (geographic information systems) as a tool for landscape design research - investigating landscape designs to understand them as architectonic compositions (architectonic plan analysis). The concept ‘composition’ refers to a conceivable arrangement, an architectural expression of a mental construct that is legible and open to interpretation. Landscape architectonic compositions and their representations embody a great wealth of design knowledge as objects of our material culture and reflect the possible treatment of the ground, space, image and program as a characteristic coherence. By exploring landscape architectonic compositions with GIS, design researchers can acquire design knowledge that can be used in the creation and refinement of a design.  The research aims to identify and illustrate the potential role of GIS as a tool in landscape design research, so as to provide insight into the possibilities and limitations of using GIS in this capacity. The critical, information-oriented case of Stourhead landscape garden (Wiltshire, UK), an example of a designed landscape that covers the scope and remit of landscape architecture design, forms the heart of the study. The exploration of Stourhead by means of GIS can be understood as a plausibility probe. Here the case study is considered a form of ‘quasi-experiment’, testing the hypothesis and generating a learning process that constitutes a prerequisite for advanced understanding, while using an adjusted version of the framework for landscape design analysis by Steenbergen and Reh (2003). This is a theoretically informed analytical method based on the formal interpretation of the landscape architectonic composition addressing four landscape architectonic categories: the basic, the spatial, the symbolic and the programmatic form. This study includes new aspects to be analysed, such as the visible form and the shape of the walk, and serves as the basis for the landscape architectonic analysis in which GIS is used as the primary analytical tool.  GIS-based design research has the possibility to cultivate spatial intelligence in landscape architecture through three fields of operation: GIS-based modelling: description of existing and future landscape architectonic compositions in digital form; GIS-based analysis: exploration, analysis and synthesis of landscape architectonic compositions in order to reveal latent architectonic relationships and principles, while utilizing the processing capacities and possibilities of computers for ex-ante and ex-post simulation and evaluation; GIS-based visual representation: representation of (virtual) landscape architectonic compositions in space and time, in order to retrieve and communicate information and knowledge of the landscape design.  Though there are limitations, this study exemplifies that GIS is a powerful instrument to acquire knowledge from landscape architectonic compositions. The study points out that the application of GIS in landscape design research can be seen as an extension of the fundamental cycle of observation, visual representation, analysis and interpretation in the process of knowledge acquisition, with alternative visualisations and digital landscape models as important means for this process. Using the calculating power of computers, combined with inventive modelling, analysis and visualisation concepts in an interactive process, opened up possibilities to reveal new information and knowledge about the basic, spatial, symbolic and programmatic form of Stourhead. GIS extended the design researchers’ perception via measurement, simulation and experimentation, and at the same time offered alternative ways of understanding the landscape architectonic composition. This gave rise to the possibility of exploring new elements in the framework of landscape design research, such as the visible form and kinaesthetic aspects, analysing the composition from eyelevel perspective. Moreover, the case study showcases that GIS has the potential to measure phenomena that are often subject to intuitive and experimental design, combining general scientific knowledge of, for instance, visual perception and way-finding, with the examination of site-specific design applications. GIS also enabled one to understand the landscape architectonic composition of Stourhead as a product of time, via the analysis of its development through reconstruction and evaluation of several crucial time-slice snapshots. The study illustrates that GIS can be regarded an external cognitive tool that facilitates and mediates in design knowledge acquisition. GIS facilitates in the sense that it can address the ‘same types of design-knowledge’ regarding the basic, spatial, symbolic and programmatic form, but in a more precise, systematic, transparent, and quantified manner. GIS mediates in the sense that it influences what and how aspects of the composition can be understood and therefore enables design researchers to generate ‘new types of design-knowledge’ by advanced spatial analysis and the possibility of linking or integrating other information layers, fields of science and data sources. The research contributes to the development and distribution of knowledge of GIS-applications in landscape architecture in two ways: (1) by ‘following’ the discipline and developing aspects of it, and (2) by setting in motion fundamental developments in the field, providing alternative readings of landscape architecture designs

GIS-based landscape design research:

Landscape design research is important for cultivating spatial intelligence in landscape architecture. This study explores GIS (geographic information systems) as a tool for landscape design research - investigating landscape designs to understand them as architectonic compositions (architectonic plan analysis). The concept ‘composition’ refers to a conceivable arrangement, an architectural expression of a mental construct that is legible and open to interpretation. Landscape architectonic compositions and their representations embody a great wealth of design knowledge as objects of our material culture and reflect the possible treatment of the ground, space, image and program as a characteristic coherence. By exploring landscape architectonic compositions with GIS, design researchers can acquire design knowledge that can be used in the creation and refinement of a design.  The research aims to identify and illustrate the potential role of GIS as a tool in landscape design research, so as to provide insight into the possibilities and limitations of using GIS in this capacity. The critical, information-oriented case of Stourhead landscape garden (Wiltshire, UK), an example of a designed landscape that covers the scope and remit of landscape architecture design, forms the heart of the study. The exploration of Stourhead by means of GIS can be understood as a plausibility probe. Here the case study is considered a form of ‘quasi-experiment’, testing the hypothesis and generating a learning process that constitutes a prerequisite for advanced understanding, while using an adjusted version of the framework for landscape design analysis by Steenbergen and Reh (2003). This is a theoretically informed analytical method based on the formal interpretation of the landscape architectonic composition addressing four landscape architectonic categories: the basic, the spatial, the symbolic and the programmatic form. This study includes new aspects to be analysed, such as the visible form and the shape of the walk, and serves as the basis for the landscape architectonic analysis in which GIS is used as the primary analytical tool.  GIS-based design research has the possibility to cultivate spatial intelligence in landscape architecture through three fields of operation: GIS-based modelling: description of existing and future landscape architectonic compositions in digital form; GIS-based analysis: exploration, analysis and synthesis of landscape architectonic compositions in order to reveal latent architectonic relationships and principles, while utilizing the processing capacities and possibilities of computers for ex-ante and ex-post simulation and evaluation; GIS-based visual representation: representation of (virtual) landscape architectonic compositions in space and time, in order to retrieve and communicate information and knowledge of the landscape design.  Though there are limitations, this study exemplifies that GIS is a powerful instrument to acquire knowledge from landscape architectonic compositions. The study points out that the application of GIS in landscape design research can be seen as an extension of the fundamental cycle of observation, visual representation, analysis and interpretation in the process of knowledge acquisition, with alternative visualisations and digital landscape models as important means for this process. Using the calculating power of computers, combined with inventive modelling, analysis and visualisation concepts in an interactive process, opened up possibilities to reveal new information and knowledge about the basic, spatial, symbolic and programmatic form of Stourhead. GIS extended the design researchers’ perception via measurement, simulation and experimentation, and at the same time offered alternative ways of understanding the landscape architectonic composition. This gave rise to the possibility of exploring new elements in the framework of landscape design research, such as the visible form and kinaesthetic aspects, analysing the composition from eyelevel perspective. Moreover, the case study showcases that GIS has the potential to measure phenomena that are often subject to intuitive and experimental design, combining general scientific knowledge of, for instance, visual perception and way-finding, with the examination of site-specific design applications. GIS also enabled one to understand the landscape architectonic composition of Stourhead as a product of time, via the analysis of its development through reconstruction and evaluation of several crucial time-slice snapshots. The study illustrates that GIS can be regarded an external cognitive tool that facilitates and mediates in design knowledge acquisition. GIS facilitates in the sense that it can address the ‘same types of design-knowledge’ regarding the basic, spatial, symbolic and programmatic form, but in a more precise, systematic, transparent, and quantified manner. GIS mediates in the sense that it influences what and how aspects of the composition can be understood and therefore enables design researchers to generate ‘new types of design-knowledge’ by advanced spatial analysis and the possibility of linking or integrating other information layers, fields of science and data sources. The research contributes to the development and distribution of knowledge of GIS-applications in landscape architecture in two ways: (1) by ‘following’ the discipline and developing aspects of it, and (2) by setting in motion fundamental developments in the field, providing alternative readings of landscape architecture designs

Airborne LiDAR for DEM generation: some critical issues

Airborne LiDAR is one of the most effective and reliable means of terrain data collection. Using LiDAR data for DEM generation is becoming a standard practice in spatial related areas. However, the effective processing of the raw LiDAR data and the generation of an efficient and high-quality DEM remain big challenges. This paper reviews the recent advances of airborne LiDAR systems and the use of LiDAR data for DEM generation, with special focus on LiDAR data filters, interpolation methods, DEM resolution, and LiDAR data reduction. Separating LiDAR points into ground and non-ground is the most critical and difficult step for DEM generation from LiDAR data. Commonly used and most recently developed LiDAR filtering methods are presented. Interpolation methods and choices of suitable interpolator and DEM resolution for LiDAR DEM generation are discussed in detail. In order to reduce the data redundancy and increase the efficiency in terms of storage and manipulation, LiDAR data reduction is required in the process of DEM generation. Feature specific elements such as breaklines contribute significantly to DEM quality. Therefore, data reduction should be conducted in such a way that critical elements are kept while less important elements are removed. Given the highdensity characteristic of LiDAR data, breaklines can be directly extracted from LiDAR data. Extraction of breaklines and integration of the breaklines into DEM generation are presented