Digital Ground Model Research Articles

Research on Visualization of Digital Ground Model Based on Satellite Image

3D printing technology has the advantages of high precision, low cost and environmental protection, and can provide a new and reliable technology for visual expression. This paper takes Qinghai Lake as the research object, uses remote sensing technology as the means to make a digital ground model, uses 3DMax software to convert geographic information data into data that can be visualized and expressed, and finally uses 3D printing technology to make a visual 3D solid model of Qinghai Lake basin. The experiment shows that 3D printing technology is feasible in the production of digital terrain model, and has broad prospects for development.

Research and development of tunnel intelligent design system

According to the characteristics of tunnel design, the tunnel BIM entity is created based on the digital ground model, forming a set of data sources, two-dimensional drawings, three-dimensional models and three expression design forms of BIM building information. The system can complete the design of tunnel building boundaries and internal contours, tunnel lining design, cave door design and auxiliary construction measures design; Among them, intelligent design is a feature of the software: the design of the cave door, lining section and auxiliary measures can be intelligently determined through the information such as the type of surrounding rock and the burial depth of the tunnel in the geological data, so as to realize the digitization and intelligence of the tunnel design. In addition, there is a template library function, a timely update function. At present, the system can meet 80% of the business needs of tunnel design, which greatly improves the design production efficiency.

Application of Multimedia Tilt Photogrammetry Technology Based on Unmanned Aerial Vehicle in Geological Survey

In order to better investigate the geological research, a tilt photogrammetry technology based on the unmanned aerial vehicle is proposed. This paper makes use of UAV tilt photogrammetry technology to make geological macroscopic analysis and establishes 3d color digital ground model, forming a set of technical methods for geological survey assisted by UAV. The experimental results show that the coordinate calculation is significantly improved, and the root mean square error of plane coordinates reaches 0.2 m, which can meet the requirements of later cartography and spatial measurement. The feasibility and efficiency of carrying out a geological survey based on the unmanned aerial vehicle are verified by the practical application in landslide hazard geological survey. It is proved that DEM and DOM data obtained based on oblique photogrammetry data can form various thematic maps by superimposing them with vector GIS data, which will provide a basic data model for subsequent engineering investigation, site management, and image display.

Digitalisierung und IoT im maschinellen Tunnelbau – Ein integraler Ansatz

AbstractThe article presents a platform approach, in which the almost complete linking of machine data analysis, Building Information Modelling, document management system and digital ground models can be carried out in real time during a mechanised tunnel drive. All processes of mechanised tunnelling are digitalised and further processed in various applications in real time. The subsequent examples should demonstrate that there are now practically no application limits to the digitalisation of tunnel construction sites. Furthermore the potential and limits of artificial intelligence and machine learning are presented.

Digital Terrain Model of the Second Military Survey – Part of the Military Training Area Brdy

The Second Military Survey in the territories of the former Austro-Hungarian Monarchy was performed between 1806 and 1869. The territory of Bohemia was surveyed from1842 to 1852 and Moravia and Silesia from 1836 to 1840. After detailed study of the Lehmann´s theory of displaying the topographic landforms using hachure’s, it was detected that the hachure’s in the maps of the Second Military Survey were created by means of the modified Lehmann´s scale. The representation of landforms in maps of the Second Military Survey was accomplished by spot heights represented mostly by points of geodetic control. The aim of this contribution is to propose and describe the methodology of creating the digital terrain model (DTM) from the Second Military Survey hypsometry and to analyse its accuracy. A part of the map sheet (W_II_11) of the Second Military Survey, representing the long-standing military training area Brdy, was chosen as a model area. The resulting DTM was compared with the recent reference digital ground model – DMR ZABAGED®. The conformity of terrain relief forms and elevation accuracy of the DTM derived from the Second Military Survey hypsometry were also investigated.

Assessing levee stability with geometric parameters derived from airborne LiDAR

A methodology to assess levee structural integrity using high resolution airborne Light Detection and Ranging (LiDAR) data is investigated for a 16 km reach of the Sacramento River within the Sacramento–San Joaquin River Delta (California). Levee geometric parameters (levee crown width, height and water and landside slopes) were extracted from 0.5 m resolution LiDAR derived digital ground models. Deviation of these parameters from minimum levee design standards was used to calculate a levee stability index. Stability maps were generated and those areas that did not meet USACE geometric shape standards were identified. Results show that 2 out of the 4 geometric parameters do not meet the minimum value required in 48% and 43% of profiles on the east (urban adjacent) and west (farmland adjacent) margins respectively. Most importantly, the crown width in 99% of the levee profiles located on the urban side was below the minimum required. The paper also points out the importance of evaluating all four geometric parameters, not just the elevation of the levee, by assessing its level of performance through a geometric assessment.

Estimation of shrub height for fuel-type mapping combining airborne LiDAR and simultaneous color infrared ortho imaging

A fuel-type map of a predominantly shrub-land area in central Portugal was generated for a fire research experimental site, by combining airborne light detection and ranging (LiDAR), and simultaneous color infrared ortho imaging. Since the vegetation canopy and the ground are too close together to be easily discerned by LiDAR pulses, standard methods of processing LiDAR data did not provide an accurate estimate of shrub height. It was demonstrated that the standard process to generate the digital ground model (DGM) sometimes contained height values for the top of the shrub canopy rather than from the ground. Improvement of the DGM was based on separating canopy from ground hits using color infrared ortho imaging to detect shrub cover, which was measured simultaneously with the LiDAR data. Potentially erroneous data in the DGM was identified using two criteria: low vegetation height and high Normalized Difference Vegetation Index (NDVI), a commonly used spectral index to identify vegetated areas. Based on the height of surrounding pixels, a second interpolation of the DGM was performed to extract those erroneously identified as ground in the standard method. The estimation of the shrub height improved significantly after this correction, and increased determination coefficients from R2 = 0.48 to 0.65. However, the estimated shrub heights were still less than those observed in the field.

Optimization of digital terrain model for its application in forestry

Digital terrain model (DTM) represents a very important geospatial data type. In the CzechRepublic, the most common digital contour data sources are the Primary Geographic Data Base (ZABAGED), the Digital Ground Model (DMÚ25) and eventually the Regional Plans of Forest Development (OPRL). In constructing regular raster DTM, the initial process requires interpolation between the points in order to estimate values in a regular grid pattern. In this study, constructions of DTM from the above-mentioned data were tested using several software products: ArcEditor 9.0, Atlas 3.8, GRASS 6.1, Idrisi 14.02 and TopoL 2001. Algorithm parameters can be optimized in several ways. In this sense a comparison of the first and second derivative of DTM and its real appearance in the terrain and a cross-validation procedure or terrain data measurements to compute and minimize the root mean square error values (RMSE) proved to be the most useful operations. The ZABAGED contour data provided the best results, with software specific algorithms for interpolations of contour data (ArcGIS Desktop Topo to Raster, Idrisi Kilimanjaro TIN).

An innovative flood forecasting system for the Demer basin: A case study

This paper describes the development and operation of the new flood forecasting system for the Demer basin in Belgium, which has suffered severe flooding problems for many years. The system takes telemetry data from a large number of hydrological, meteorological, and hydraulic observation sites across the basin, along with radar rainfall forecasts. These data are fed through a network of complex hydrological and hydrodynamic models. Scheduled runs of the system take place at frequencies determined by the level of alert; runs are performed on a cluster of server computers, then results are available on client computers in the control room and via remote access. This gives operational basin managers fast, accurate, real‐time flood forecasting and flood mapping based on high‐resolution digital ground model information, enabling identification of those streets and areas affected by flooding. The basin managers have several options for diverting flood waters in order to avoid or mitigate the effects of flood events in key areas. The forecast results underpin a decision‐support system, giving basin managers the information they need to make informed judgements for disseminating flood warnings and altering their management of the river controls.

THE MAPPING OF NORTHERN GREENLAND

AbstractApproximately 110 sheets of orthophotomaps at a scale of 1:100000 covering all the ice, free area (300000 km2) of northern Greenland are to be produced by the Geodetic Institute of Denmark. Super‐wide angle photography at a scale of 1:150 000 was acquired in 1978. Individual models are set up in a Wild B8S stereoplotter and, after carrying out aerial triangulation, a numerical method of absolute orientation is used. A digital ground model of the entire area is established in order to enable the interpolation of contour lines, for automatic plotting and to produce control data, for the orthophotoprojector. a Wild OR1. Methods of data handling and control, accuracies and typical errors are discussed.

DIGITAL GROUND MODELS: AN ACCOUNT OF RECENT RESEARCH

AbstractThe article discusses a general classification system applicable to digital ground models (D.G.M.) as used in highway design. Examples of the various categories are given, together with details of some advantages and disadvantages. The place of the D.G.M. in the highway design system is described in conjunction with traditional methods. The relationship between accuracy, density and economy of D.G.M. systems is examined. Finally an experiment is described which investigates the accuracy of various D.G.M. systems; it is being conducted by the Transport and Road Research Laboratory.