Structural Parameters for Hybrid DTM Generalization

2016

Modeling land surface is a particular case of modeling the areas which need special consideration for specific issues related to Earth representation or some parts of the terrestrial crust. This study had as main objective the achievement of a digital terrain model in a mountain area based on Triangulated Irregular Network (TIN). This studied area represents a part of the Retezat Mountains. The images obtained were analyzed with ArcGIS software. The database and algorithms used facilitated the creation of a 3D model for the studied area, with a spatial distribution similar to the real situation in the field. The obtained 3D model facilitated the graphical representation of different types of slopes, grouped into 6 classes at intervals of 10 units, according to slope values, covering 100% of the study area. The largest coverage consists of land with slopes between 10-40%. The 3D model also facilitated graphical and numerical representation of aspect and it allowed the Hillshade model...

Glasnik srpskog geografskog dru?tva, 2005

Садржај: У раду је дат преглед савремених метода прикупљања података за потребе израде Дигиталних Модела Tерена (ДМТ), као и тачност података која ове методе обезбеђују. На примеру дигиталног модела добијеног дигитализацијом картографског садржаја основне државне карте, и теренских мерења ГПС технологијом и аерофотограметријских мерења приказан је поступак оцене оваквих база података о рељефу.

International journal of geographical information …, 2005

The objective of this paper is to discuss methods of producing a digital terrain model (DTM) from different quality datasets. The current quantity of DTMs and other spatial databases offers potential for an enhanced production of DTMs with a better quality than is currently obtainable. Two methods of integrating different datasets are described in this paper. The first is based on the simultaneous interpolation of all useful spatial data sources, and is supported by a proper prediction function according to the weights. The second -weighted sum of data with geomorphologic enhancement -sequentially combines individual datasets according to their weights and is maintained by geomorphologic enhancement. The weights in both methods depend on the output of the used spatial datasets quality control. The methods are tested with regard to original methodological solutions of DTM production developed for the integration of datasets.

Istituto per la Matematica Applicata -Consiglio Nazionale delle Ricerche Storage, manipulation and rendering of huge data sets are frequently required in spatial data handling and need memory and processing resources beyond the available ones, especially in real-time or interactive environments. Thus it is necessary to define data models which use the minimum amount of data for retrieving the maximum of information possible, and modelling issues have to be considered in addition to traditional hardware or software optimisation problems.

National mapping agencies in North American and western Europe have released free lidar point clouds with densities of 2-23 points/m², and derived terrain grids. Geomorphometric processing uses a bare earth digital terrain model (DTM), which can be acquired from mapping agencies or created from the point cloud to better control its characteristics. Free software provides tools for noise removal, ground classification, surface generation, void filling, surface smoothing, and hydraulic conditioning. Tests with three ground classification algorithms, and four surface generation algorithms show that they produced very similar results. The main issues for geomorphometric operations on DTMs involve whether the highest and lowest ground points should be in the DTM if they are not on a grid node, how water, buildings, and roads should be treated, if using a DTM of lower resolution will effectively filter out noise and allow much faster processing, and if lower resolution DTMs should be crea...

Geomorphometry, by its analytical approach, contributes towards understanding landscape shapes and processes that generate them. The automation of relief's feature extraction is in a transition period and has now to lead the users to practical solutions in their systems. This corresponds also to the emergence of a great variety of acquisition modes for DTM, and a fast-growing production of elevation data. The scope of this study aims to provide a practical illustration of geomorphometric descriptive parameters extraction. First, on the basis of simple criteria linked to the digital representation of the altitude, for which a hypothesis of modelling by polynomial regional so-called "translated functions" is introduced, the various slopes and curvatures will be represented analytically. From this base, more complex and pertinent criteria for geomorphometric features will be suggested. The survey will provide an analytical foundation for the description of the relief aimed at all those who study relief evolution processes. From the geographer point of view, this approach confirms past evolutionary processes leading to present landscape shapes and explains the role of these shapes in current and ongoing erosion phenomena by using digital data. The analytical geometric analysis provided and the objects recognized help the settlement of environmental database. Therefore, the DTM finds its place as an operationnal cornerstone data in the GIS, dedicated to the standard geo-spatial applications, and joins the tools involved by the resource and environmental monitoring.

Journal of Geography and Environmental Management, 2017

Nowadays the requirements for topographic and geodetic products are becoming more important and gaining direct economic importance due to the high rate of market development. The main requirement remains the reliability and differentiation of the results of cartographic materials, and the most important issue is the accuracy of the developed products. The accuracy is affected by a variety of factors, depending both on the means of measurement and the type of processing. This paper presents an overview of modern survey methods for the projecting of linear structures based on the example of road sections in Almaty. Currently, the design of roads is, as a rule, based on topographic survey data, performed by traditional geodetic instruments. It is necessary to apply the automatic projecting system containing components of software, information, technical and organizational support to increase the quality of solutions on projecting objects. This article considers automated approaches for efficient data processing, comparative analysis of software complexes that are widely used to create digital terrain models, their ability to support and create three-dimensional models, import of point cloud, a way of constructing relief, importing and processing initial data.

The photogrammetric method of DTM generation in built-up areas is investigated. New filtering and classification approaches are presented. Results of practical tests with the suggested processing of the 3D point clouds are analyzed. The obtained results of two tests (16 cm and 17 cm in the standard deviation and 14 cm and 18 cm in the 68% quantile) using large format images from 1000 m altitude are considerably better than the results with the raw data. The potential of the photogrammetric method for DTM generation is summarized and a comparison with airborne laser scanning is made. Applications like the extraction of buildings from dense point clouds or the completion and updating of existing DTMs could take advantage of using the photogrammetric approach.

2000

Models of ground surface elevation, slope, aspect, curvature, roughness, deformation, as well as other features are gathered together in the term Digital Terrain Model (DTM). DTMs can be generated from a wide range of technologies such as ground surveying, aerial and satellite imagery, including both active and passive sensors. Some elevationderived parameters, such as roughness and slope can be measured directly using innovative active sensor technology and smart processing, rather than via traditional processing of elevation information. Such models are used as part of a visual interpretation process, and increasingly for computer-assisted analysis, including data correction and modelling applications. There is an ever-increasing demand for DTM information to be used in the mineral exploration and mining industry, and consistent pressure from industry to develop models of higher spatial resolution, higher accuracy, and better overall reliability, regardless of the world-wide location of interest.

Research Journal of Agricultural Science, 2013

Surface modeling is the process of plotting a natural or artificial surface through one or more mathematical equations. Modeling land surface modeling is a particular case of the areas that need to be taken of the specific issues related to the representation of the earth or parts of it. Digital model of an object or phenomenon, consists of a collection of data stored systematically (database) describing a three-dimensional coordinate system, arbitrary or particular characteristics of the object or form their states / achievements phenomenon (conversion as digital image) and allow adequate computer programs deduction form and characteristics of the object or phenomenon achievements Star new points. Digital model of the terrain is a "tool" information consisting of field data and software is a key component of a GIS. DEM consists of an ordered set of planimetric position information and share the points that describe the spatial configuration of the structures carrying reli...