3D Terrain Model Research Articles

Seamless 3D Image Mapping and Mosaicing of Valles Marineris on Mars Using Orbital HRSC Stereo and Panchromatic Images

A seamless mosaic has been constructed including a 3D terrain model at 50 m grid-spacing and a corresponding terrain-corrected orthoimage at 12.5 m using a novel approach applied to ESA Mars Express High Resolution Stereo Camera orbital (HRSC) images of Mars. This method consists of blending and harmonising 3D models and normalising reflectance to a global albedo map. Eleven HRSC image sets were processed to Digital Terrain Models (DTM) based on an opensource stereo photogrammetric package called CASP-GO and merged with 71 published DTMs from the HRSC team. In order to achieve high quality and complete DTM coverage, a new method was developed to combine data derived from different stereo matching approaches to achieve a uniform outcome. This new approach was developed for high-accuracy data fusion of different DTMs at dissimilar grid-spacing and provenance which employs joint 3D and image co-registration, and B-spline fitting against the global Mars Orbiter Laser Altimeter (MOLA) standard reference. Each HRSC strip is normalised against a global albedo map to ensure that the very different lighting conditions could be corrected and resulting in a tiled set of seamless mosaics. The final 3D terrain model is compared against the MOLA height reference and the results shown of this intercomparison both in altitude and planum. Visualisation and access mechanisms to the final open access products are described.

Identifying optimal graphical level of detail to support orienting with 3D geo-visualizations

ABSTRACT Limited hardware processing capacities and network bandwidth constrain the quality and quantity of photogrammetrically derived 3D terrain models that users can effectively visualize. In the present study, we examined what graphical level of detail (LOD) is sufficient to support effective spatial localization and orientation in 3D renderings of large-scale environments. We developed an interactive desktop split-screen orienting and geo-visualization task using photogrammetrically derived 3D terrain models, manipulating LOD on a trial-by-trial basis, tracking interactions during geo-visualization, and measuring orienting performance. Results demonstrated moderate (rather than maximum) LOD is sufficient for spatial orientation, suggesting new guidelines for the collection, transmission, and visualization of terrain models on end-user devices. We discuss these findings within the context of spatial perception, cognition, and behavior.

TouchTerrain—3D Printable Terrain Models

TouchTerrain is a simple-to-use web application that makes creating 3D printable terrain models from anywhere on the globe accessible to a wide range of users, from people with no GIS expertise to power users. For coders, a Python-based standalone version is available from the open-source project’s GitHub repository. Analyzing 18 months of web analytics gave us a preliminary look at who is using the TouchTerrain web application and what their models are used for; and to map out what terrains on the globe they chose to 3D print. From July 2019 to January 2021, more than 20,000 terrain models were downloaded. Models were created for many different use cases, including education, research, outdoor activities and crafting mementos. Most models were realized with 3D printers, but a sizable minority used CNC machines. Our own experiences with using 3D printed terrain in a university setting have been very positive so far. Anecdotal evidence points to the strong potential for 3D printed terrain models to provide significant help with specific map-related tasks. For the introductory geology laboratory, 3D printed models were used as a form of “training wheels” to aid beginning students in learning to read contour maps, which are still an important tool for geology.

СОЗДАНИЕ И ИСПОЛЬЗОВАНИЕ 3D-МОДЕЛИ ГОРНОГО РЕЛЬЕФА ДЛЯ ГЕОИНФОРМАЦИОННОГО ОБЕСПЕЧЕНИЯ ТУРИЗМА

The article deals with the creation and use of a 3D model of mountain terrain for geoinformation support of tourism in the Russian Federation on the example of the territory of the Republic of In-gushetia. The aim of the work is to develop and apply a digital 3D model of mountain terrain for use in creating an interactive tourist map on web services, as well as tourist and administrative sites of the republics of the Caucasus. Methods of geoinformational mapping, terrain modeling, cartographic research method and modern software were used: 3D Spatial Analysts, WorldMachine, Unity 3D. The classification of tourism types and objects of natural and cultural heritage in the Republic of Ingushetia is carried out. As a result of the analysis of tourist and administrative sites, as well as web-services of the republics of the Caucasus, a conclusion is made about their insufficient geoinformation support. The possibilities of using 3D models of mountain terrain on web maps for tourism purposes are pre-sented. A digital model of mountainous landform in the Republic of Ingushetia is created. A 3D scene, which shows basic relief forms and objects’ location is developed.

ИСПОЛЬЗОВАНИЕ ДЗЗ И ГИС ПРИ СОЗДАНИИ ГЕОГРАФИЧЕСКИХ ОСНОВ ДЛЯ ТЕМАТИЧЕСКИХ КАРТ

The development of science always depends on technological progress. Cartography is rapidly changing and developing with the introduction of new computer technologies, such as GIS and remote sensing of the Earth. Recently, there have been qualitatively new types of cartographic products, in particular 3D terrain models, which in cartography are becoming a universal, optimal and operational method for displaying terrain. The article discusses a method for creating a three-dimensional digital terrain model in the form of an irregular triangulation network based on SRTM data and GIS technology on the example of the Khenti aimag of Eastern Mongolia.

Geomorphology and Landslide Proneness of Kerala, India A Geospatial study

It was thought for a long time that only the younger and tectonically active mountains are prone to landslides and hence more attention was given in studying them the world over. But, when the landslides have started occurring in other mountain regions of high rainfall and human interventions also, these mountains too came under the purview of landslide studies. The studies thus widened to the other mountains revealed that the various geological/terrain parameters and the degree of anthropogenic activities occur in different combinations and assign varying grades of landslide probabilities. According to it, these mountains succumb to different degrees of landslides when heavy rainfall occurs. The state of Kerala, which is 600 km long in North Northwest–South Southeast and 35 to 120 km broad in East-West directions, is one such a region of recurring landslides. It is a unique physiographic/geomorphic province with highly elevated NNW-SSE oriented Western Ghat Mountains in the east, that are rimmed by the sub parallel systems of landforms like composite slopes, marginally raised lateritic uplands and the coastal plains successively in the west with gradual descending elevation, thus providing a step like topography. The regular annual rainfall of the southwest monsoons cause devastating landslides in Kerala due to the unique geomorphic setting. So the present study was carried out to analyse the geomorphology of the region in details, which is dominantly evolved by the tectonics, to elucidate its input over the landslides. In the study, the geomorphic features were studied in detail using the (i) satellite false colour composite imagery wrapped over the digital elevation model of the terrain, (ii) shaded relief maps and (iii) the topographic cross sections drawn over the above satellite data wrapped 3D terrain model. These were accomplished using the advanced options available with geospatial technology. The study revealed that due to the high degree of deformation and the resultant development of geomorphology of the study area, the rainwater infiltrates and cause landslides in the form of rock and cliff topples, rock and cliff falls, landslides, talus and debris falls/flows.

Optimization Analysis of Suki Kinari Underground Powerhouse Caverns Based on an Efficient CATIA-Abaqus Model

Underground powerhouse caverns, which are large-scale, complex-type, and intersecting circuits, are considered as a complicated, constrained, and irreversible nonlinear system. They are divided into several layers for excavation. Various stress states occur whenever they are subjected to excavation; therefore, deformation and failure arise because of stress redistribution and concentration. Based on the determinate excavation scheme, the sectional shape of underground powerhouse caverns, especially the aspect ratio of the main powerhouse, is the key factor that affects the stability of the surrounding rock masses. Furthermore, during the excavation process, the integrity and stability of rock pillar, whose thickness is determined by the interval of caverns, are considered as crucial issues, because damage occurs in the thinner rock pillar. Consequently, the interval of caverns is the important parameter that needs to be investigated. In this study, we combine building information modeling with numerical analysis to investigate the effect of the aspect ratio of the main powerhouse and the interval between the main powerhouse and the main transform chamber. For the Suki Kinari (SK) underground powerhouse caverns, the 3D terrain and geological model was created in accordance with the detailed geological information. The parameterized underground powerhouse model and the supporting system were designed by CATIA, and the numerical model that involves the excavation scheme was generated by ABAQUS. The results show the following: (1) As the aspect ratio increases, the deformation of the main powerhouse exhibits various features, indicating that the arch crown settlement reduces while the deformation of the sidewalls increases. (2) As the aspect ratio increases, the overall deformation of the particular parts exhibits the characteristic of rapidly decreasing and then gradually forming a convergent trend. (3) Intense disturbance occurs on the rock pillar because of bidirectional unloading during the excavation process, and the rock pillar weakens rapidly and then gradually stabilizes as the thickness increases, suggesting the property of exponential function of the total deformation. Finally, the conclusions are applied on the SK underground powerhouse caverns to reveal the optimal aspect ratio and interval.

SYNTHETIC VISION SYSTEM CALIBRATION FOR CONFORM PROJECTION ON THE PILOT’S HEAD-UP DISPLAY

Abstract. Situational awareness of the crew is critical for the safety of the air flight. Head-up display allows providing all required flight information in front of the pilot over the cockpit view visible through the cockpit’s front window. This device has been created for solving the problem of informational overload during piloting of an aircraft. While computer graphics such as scales and digital terrain model can be easily presented on the such display, errors in the Head-up display alignment for correct presenting of sensor data pose challenges. The main problem arises from the parallax between the pilot’s eyes and the position of the camera. This paper is focused on the development of an online calibration algorithm for conform projection of the 3D terrain and runway models on the pilot’s head-up display. The aim of our algorithm is to align the objects visible through the cockpit glass with their projections on the Head-up display. To improve the projection accuracy, we use an additional optical sensor installed on the aircraft. We combine classical photogrammetric techniques with modern deep learning approaches. Specifically, we use an object detection neural network model to find the runway area and align runway projection with its actual location. Secondly, we re-project the sensor’s image onto the 3D model of the terrain to eliminate errors caused by the parallax. We developed an environment simulator to evaluate our algorithm. Using the simulator we prepared a large training dataset. The dataset includes 2000 images of video sequences representing aircraft’s motion during takeoff, landing and taxi. The results of the evaluation are encouraging and demonstrate both qualitatively and quantitatively that the proposed algorithm is capable of precise alignment of the 3D models projected on a Head-up display.

UAV MISSION PLANNING FOR AUTOMATIC EXPLORATION AND SEMANTIC MAPPING

Abstract. Unmanned Aerial Vehicles (UAVs) are used for the inspection of areas which are otherwise difficult to access. Autonomous monitoring and navigation requires a background knowledge on the surroundings of the vehicle. Most mission planing systems assume collision-free pre-defined paths and do not tolerate a GPS signal outage. Our approach makes weaker assumptions. This paper introduces a mission planing platform allowing for the integration of environmental prior knowledge such as 3D building and terrain models. This prior knowledge is integrated to pre-compute an octomap for collision detection. The semantically rich building models are used to specify semantic user queries such as roof or facade inspection. A reasoning process paves the way for semantic mission planing of hidden and a-priori unknown objects. Subsequent scene interpretation is performed by an incremental parsing process.

3D MAP SYSTEM FOR TREE MONITORING IN HONG KONG USING GOOGLE STREET VIEW IMAGERY AND DEEP LEARNING

Abstract. In densely built urban areas such as Hong Kong, the positive effect of urban trees is to help maintain high environmental and social sustainability for the city while unmanaged trees lead to negative effects such as accidents, outbreaks of pests and diseases. The public awareness of urban tree population has been increasing and preserving all the benefits offered by trees, a continuous monitoring concept would be required. In this work, an efficient 3D map system for tree inventory in Hong Kong is presented to the based on automated tree detection from publicly available Google street view (GSV) panorama images. First, Convolutional Neural Networks (CNNs) based object detector and classifier – YOLOv3 with pretrained model is adopted to learn GSV images to detect tree objects. GSV depth image has been utilized to decode depth values of each GSV panorama image and will provide accurate information to calculate the tree geographic position. A “field of view” filter was designed to remove duplicated tree detection within the overlapped areas followed by spatial clustering applied to further increase the tree localization accuracy. The average distance between the detected trees and ground truth data was achieved within 3 meters for selected roads used for the experiment. Second, a 3D Map platform prototype for facilitating the urban tree monitoring and management was developed. Currently, there is no true 3D platform for interpreting the results of tree records in Hong Kong city areas. With the help of webGL technology, contemporary browsers are able to show 3D buildings, terrain and other scene components together with the obtained tree records in an open source 3D GIS platform, the level of visualization is enhanced as all the detected trees are placed on the 3D digital terrain model. Consequently, it is easy for end-users to know the actual position of the trees and their distribution.

NEW DIRECTIONS OF USING 3D-MODELING

The article discusses the concept of three-dimensional modeling, shows the main areas of application of 3D models in the modern world and their significance for humans. The main advantages of 3D models in comparison with a two-dimensional model are described. Shows which software products are used to create 3D terrain models.

Use of new technologies in water resources prospecting—A case study on Karst of the Polanco Formation, Uruguay

Hydrogeological background motivated the development of prospective groundwater models in carbonate rocks of the Polanco Formation (Ediacaran). Field and photographic surveys were carried out (SGM, Google Earth and Drone Phantom 2 Vision+), and 3D terrain models were generated to interpret the morpho-structural characteristics of the karst relief. Boreholes and geoelectric data were surveyed. Standard prospective techniques were complemented with remote ground access technologies to generate a specific prospective model for these lithologies. As a result, it was found the existence of folds that generate an inverted relief with “cup” and “tube” type dolines, a karst relief type lapiaz, three springs and the development of wells with an average flow of 30 m3/h. The hydrogeochemical composition corresponds to bicarbonate-calcium waters of natural mineral water quality.

The Paleo topography of Neungheodae and its Surrounding Areas Using 3D Terrain Analysis

능허대는 백제시대 외국 사신의 출항과 입항이 이루어지던 장소로 알려져 있다. 하지만 능허대와 그 주변은 대규모 도시 개발로 인해 현재는 원지형을 거의 살필 수 없다. 따라서 선박 장소로서의 능허대를 정확히 파악하기가 쉽지 않다. 이의 해결을 위해 고지형분석 방법을 이용한 능허대와 주변의 지형을 살핌으로써 선박장소로서 능허대의 가능성을 파악하고자 하였다. 고지형분석은 미시적이고 거시적 관점에서 지형의 3차원 판독을 진행하였으며, 이와 함께3차원 지형 모델링 복원하여 해수면의 변동 분석을 같이 실시함으로써 능허대와 주변 일대의선박장소로서의 적합한 지형을 파악하고자 하였다. 그러한 방법을 바탕으로 고지형 분석을 실시한 결과 능허대와 그 주변은 구릉지와 야트막한 미고지성 지형으로 이루어진 모습을 살펴볼수 있었으며, 동쪽의 청량산에서부터 발원한 구유로가 동에서 서쪽으로 흐르는 것을 확인하였다. 더불어 능허대의 동쪽 사면에 접한 곳으로는 선박의 정박이 이루어질 수 있는 넓은 집수지성지대와 함께 작은 어선의 입출항이 가능할 수 있는 갯골 등의 흔적도 파악하였다. 이러한 분석결과를 통해 능허대는 배의 정박 장소보다는 주변 경관을 조망하기 좋은 장소로서의 기능이 우선하였던 것으로 이해되었고, 오히려 선착장으로서의 지형은 능허대의 동쪽, 고지도에 표시된 한진의 지명이 있는 지형이 유력할 가능성을 제시하였다. 물론 능허대와 주변의 지형들은 항만의 자연 입지 조건에 부합하는 모습이 명확하고 물자와 인력이 이동하기에 좋은 자연지형을 갖추고 있어 경제적 조건의 항만 입지와도 일치한다. 이러한 입지조건 파악을 통해 백제및 중국 사신들의 사행 이동로의 지형도 같이 파악할 수 있었으며 나아가 이동의 방향 등도살펴볼 수 있었다.Neungheodae is known to be the location where the port entry and exit of foreign envoys occurred during the Baekjae period. However, the original topography of Neungheodae and its surrounding areas is almost impossible to find due to large-scale urban development. Therefore, it is not easy to accurately pinpoint Neungheodae as a docking location. That is why I aimed to determine the possibility of the ferry landing as a docking place by examining the paleotopography of Neungheodae and its surrounding areas using 3D terrain analysis. The 3D terrain analysis is a paleotopography method that deciphers terrain from microscopic and macroscopic perspectives. By conducting a sea level change analysis using the 3D terrain analysis together with the 3D terrain modeling reconstruction, I attempted to identify the terrain at Neungheodae and its surrounding areas that were found to be suitable for docks. The results of the terrain analysis based on that methodology showed that Neungheodae and its surrounding areas were composed of hills and low minute hilly terrain (slightly raised ground), and I also found that the old Gokbu river, which originates from Mt. Cheongnyang in the east, flowed from the east to the west. In addition, I also discovered that there was a large receiving basin area where boats could anchor next to the eastern slope of Neungheodae, as well as the traces of tidal channels where small fishing boats could enter and exit the dock. Through these analysis results, I proposed that the main function of Neungheodae was prioritized as a location to afford a view of the surrounding landscape rather than as a location for boats, and that the possibility that the slightly raised ground to the east of Neungheodae, the location noted as Hanjin in old maps, was rather more suitable as a dock. Above all, the topography of the ferry landing and its surrounding areas have natural geographical conditions that clearly made it suitable as a dock, and it has economically advantageous geographical conditions as it has terrain that is naturally suited for the movement of goods and people. By understanding these geographical conditions, I could examine the routes that Baekjae and Chinese envoys took, as well as the direction of their routes.

Terrain Point Cloud Assisted GB-InSAR Slope and Pavement Deformation Differentiate Method in an Open-Pit Mine.

Ground-based synthetic aperture radar interferometry (GB-InSAR) is a valuable tool for deformation monitoring. The 2D interferograms obtained by GB-InSAR can be integrated with a 3D terrain model to visually and accurately locate deformed areas. The process has been preliminarily realized by geometric mapping assisted by terrestrial laser scanning (TLS). However, due to the line-of-sight (LOS) deformation monitoring, shadow and layover often occur in topographically rugged areas, which makes it difficult to distinguish the deformed points on the slope between the ones on the pavement. The extant resampling and interpolation method, which is designed for solving the scale difference between the point cloud and radar pixels, does not consider the local scattering characteristics difference of slope. The scattering difference information of road surface and slope surface in the terrain model is deeply weakened. We propose a differentiated method with integrated GB-InSAR and terrain surface point cloud. Local geometric and scattering characteristics of the slope were extracted, which account for pavement and slope differentiating. The geometric model is based on a GB-InSAR system with linear repeated-pass and the topographic point cloud relative observation geometry. The scattering model is based on k-nearest neighbor (KNN) points in small patches varies as radar micro-wave incident angle changes. Simulation and a field experiment were conducted in an open-pit mine. The results show that the proposed method effectively distinguishes pavement and slope surface deformation and the abnormal area boundary is partially relieved.

Study on 3D Terrain Generation and Lightweighting Method of Highway

BIM technology is widely used in highway engineering projects. During the transformation of 2D design and application to 3D, especially for special strip projects such as highways, 3D terrain has problems such as large loading efficiency and low efficiency. Based on the Beijing-Shanghai Highway reconstruction and expansion project, this paper studies the three-dimensional terrain generation and lightweight conversion methods of highway. The terrain construction method is optimized during the formation phase of the terrain, and the polygon is triangulated using the triangular surface growth algorithm. By generating the PHM (Polyhedral Mesh) terrain surface, a three-dimensional terrain model with no deviation, small volume and high generation efficiency is realized. The lightweight 3D terrain model generated by the modeling software can further simplify the 3D terrain and realize the pyramid terrain model with different loading accuracy with different sight distance through grid conversion and tin buffer generation. At the same time, the terrain is projected on satellite images, and The surrounding scenes are deeply fused. The results show that the lightening of terrain in the modeling stage is conducive to improving the modeling efficiency, eliminating the problems of large volume and stuttering of conventional terrain models, and improving the efficiency of terrain export. In the application phase, format conversion and pyramid loading are performed on the terrain, and the lightweight loading of the terrain model is truly realized. The terrain model is seamlessly integrated with the BIM road and other models, and at the same time, it covers elements such as satellite films, enabling real-time browsing based on the B / S (Brower/Server).

ОЦЕНКИ ИЗМЕНЕНИЯ РЕЛЬЕФА БЕРЕГОВОЙ ЗОНЫ ПРИ АБРАЗИИ ПО ДАННЫМ ДИСТАНЦИОННОГО ЗОНДИРОВАНИЯ: МЕТОДИЧЕСКИЕ ПОДХОДЫ И ПРЕДВАРИТЕЛЬНЫЕ РЕЗУЛЬТАТЫ

The article offers a method for assessing changes in the relief of the Azov sea coastline and the localization of areas of erosion using discrete surface models obtained from remote sensing of the Earth using unmanned aerial vehicles (UAVs). This problem arises because of the need to monitor the dynamics of the coastline: due to the activation of various natural and man-made processes, there is an intensive destruction of the shores of the seas of Russia. Existing modern methods of land topographic survey do not allow you to quickly get information about changes in the state of the coastline or are expensive, and the large extent of the zone subject to erosion makes the traditional instrumental approach of measuring at reference points very labor-intensive. Also, the data obtained by the instrumental method reflects the problem point-by-point, rather than along the entire coastline. In this paper, we developed an algorithm and software for building a three-dimensional terrain model (using Delaunay triangulation) based on the so-called “dense point cloud” obtained when shooting terrain from an unmanned aerial vehicle (UAV). we proposed and programmatically implemented an algorithm for comparing (subtracting) two 3D models based on surveys performed by the same camera, but at different times of the day, in different seasons, and at different heights with an interval of 2 years, to identify significant changes in terrain in the area of the coastal slope, caused by abrasive and collapse processes. Experimental studies of the developed approach were conducted at the test site (500 by 300 m in size) on the southern shore of the Taganrog Bay. As a result of the considered experimental studies of comparing two 3D terrain models based on dense point clouds, additional working hypotheses (steps) that need to be solved were formulated to identify significant differences due to the destruction of the coast

The application of artificial immune algorithm to earthquake relief route planning

After an extreme earthquake attacks an urban area with many mountains, the main objective of a search and rescue operation is to minimize the number of fatalities. Therefore the task of transportation rescue resources to operational areas is of great importance to disaster managers. This paper presents a quick path planning method based on Artificial Immune Algorithm (AIA) and helicopter operation performance in order to design an optimal path for an operational area. First, a simulation of an earthquake is implemented in environment only including terrain threat. Second, a more complex model contains terrain, weather, building and communication threats simulation is executed and the resulting performance measures are evaluated by considering the survival time and total value for taken out entrapped occupants in the disaster area. Additionally, the best parameters of planning path for dual helicopters to an operational area are determined. Further work will be dedicated to adding real 3D terrain model into the current threat model.

DRONE BASED NEAR REAL-TIME HUMAN DETECTION WITH GEOGRAPHIC LOCALIZATION

Abstract. Detection of humans, e.g. for search and rescue operations has been enabled by the availability of compact, easy to use cameras and drones. On the other hand, aerial photogrammetry techniques for inspection applications allow for precise geographic localization and the generation of an overview orthomosaic and 3D terrain model. The proposed solution is based on nadir drone imagery and combines both deep learning and photogrammetric algorithms to detect people and position them with geographical coordinates on an overview orthomosaic and 3D terrain map. The drone image processing chain is fully automated and near real-time and therefore allows search and rescue teams to operate more efficiently in difficult to reach areas.

A machine learning approach to modelling solar irradiation of urban and terrain 3D models

• Solar irradiation predictive machine learning models are proposed. • Models use SVF and surface orientation as predicting features. • Parametric simulations using RADIANCE generate training sets. • Gradient boosting is used and tuned using cross-validation. • The models perform well on terrains but caution is advised for cities.

Three-dimensional desktop morphometric models for the Arctic Ocean floor

Abstract. We present results of the first phase of an ongoing project to create a system for three-dimensional (3D) geomorphometric modeling of the Arctic Ocean submarine topography. In this phase, we developed a testing, lowresolution desktop version of the system. We utilized a small, 5-km gridded digital elevation model (DEM) extracted from the International Bathymetric Chart of the Arctic Ocean (IBCAO) version 3.0. From the smoothed DEM, we derived digital models of several morphometric variables: horizontal, vertical, minimal, and maximal curvatures, catchment and dispersive areas, as well as topographic and stream power indices. To construct and visualize 3D morphometric models, we applied an original approach for 3D terrain modeling in the environment of the Blender package, free and open-source software. Finally, we present a series of 3D morphometric models with perspective views from the Atlantic, Eurasia, the Pacific, and North America. The experiment showed that the approach is efficient and can be used for creating next, desktop and web versions of the system for visualizing 3D morphometric models of higher resolutions.