Reljefas yra trimatis, todėl turėtų būti taip ir vaizduojamas. Šiuolaikiniai reljefo modeliavimo programiniai paketai leidžia kurti naujus trimačius skaitmeninius reljefo vizualizavimo būdus, kurie yra lengviau suprantami vartotojų ir naudojami daugelyje sričių. Skaitmeninio reljefo modelio kūrimo procesas susideda iš duomenų rinkimo, modelio kūrimo ir jo vizualizacijos. Nedidelių teritorijų reljefo kartografavimui geriausia naudoti aukšto tikslumo GPS duomenis. Kuriant skaitmeninį reljefo modelį tikslinga pasirinkti tam tinkamiausią interpoliavimo metodą, atsižvelgiant į reljefo pobūdį, tinkamą metodo grafinę išraišką, atsirandančias paklaidas bei kompiuterio techninius parametrus, o vizualizacijai pasirinkti tokias modeliavimo priemones, kurios užtikrintų korektiško trimačio vizualizavimo praktiškumo, kartografinio dizaino, modeliavimo ir demonstravimo funkcijas bei naudoti tinkamus vizualizavimo būdus. Naudojantis SURFER 8 programa bei GPS duomenimis sukurtas Aukuro kalno piliakalnio skaitmeninis trimatis reljefo modelis. / The terrain surface is three-dimensional and should be treated like that. Modern 3D modelling computer programs allows to create new three-dimensional digital relief models, which are user-friendly and are used in many applications. Digital relief models creation process consist of data collecting, model making and it’s visualisation. For mapping small territories best method to collect data is GPS. When creating digital relief model, it is necessary to choose best interpolation method considering relief format, it’s graphics, standard deviation and computer technical parameters, and for visualisation choose such programs, which is capable to make correct three-dimensional practical, cartographical design, modelling and demonstrational functions as well as use right visualisation ways. Using SURFER 8 program and GPS data, Aukuras hill mound digital three-dimesional relief model was created.

Topicality of the research. In compiling digital terrain models (DTM) as well as in evaluating them there are widely applied mathematical statistical measuring data processing and analysis methods. However in compiling digital models of relief and evaluating them there are certain peculiarities in mathematical statistical data application. These peculiarities are caused by the fact that relief modeling as well as analysis is considered to belong to the group of geostatic problems. The latter are peculiar for the initial results of measuring which are medium between purely random and purely determined sizes. In solving geo-statistical problems, one has to make use of regionalized data, the stochastic characteristics are the functions of geographic positions of the territory. In modeling the relief the surface geomorphologic peculiarities determine the characteristics of the functions of geographical position. Theoretical grounding of the methods used in modeling the relief surface (e.g., kriging, spline, invert distance weight (IDW), polynomal) is based on the statistical analysis of the random values. Due to the fact that the characteristics of geo-statistical measuring data are preconditioned by the geographic position, not in all territories there are equally suitable certain methods of modeling and parameters of modeling algorithms. The mentioned above reasons determine the fact that there do not exist unified digital terrain modeling methods and types, to be equally well... [to full text]

Topicality of the research. In compiling digital terrain models (DTM) as well as in evaluating them there are widely applied mathematical statistical measuring data processing and analysis methods. However in compiling digital models of relief and evaluating them there are certain peculiarities in mathematical statistical data application. These peculiarities are caused by the fact that relief modeling as well as analysis is considered to belong to the group of geostatic problems. The latter are peculiar for the initial results of measuring which are medium between purely random and purely determined sizes. In solving geo-statistical problems, one has to make use of regionalized data, the stochastic characteristics are the functions of geographic positions of the territory. In modeling the relief the surface geomorphologic peculiarities determine the characteristics of the functions of geographical position. Theoretical grounding of the methods used in modeling the relief surface (e.g., kriging, spline, invert distance weight (IDW), polynomal) is based on the statistical analysis of the random values. Due to the fact that the characteristics of geo-statistical measuring data are preconditioned by the geographic position, not in all territories there are equally suitable certain methods of modeling and parameters of modeling algorithms. The mentioned above reasons determine the fact that there do not exist unified digital terrain modeling methods and types, to be equally well... [to full text]

Geografinei informacijai apie erdvinį žemės paviršių kaupti pastaruoju metu vis dažniau naudojamas vietovės skenavimo lazeriu iš orlaivio metodas LIDAR (Light Detection and Ranging). Šiuo metodu gaunama nereguliari taškinė labai tanki trijų dimensijų žemės paviršiaus objektų išsidėstymą sumodeliuojanti geometrinė ir radiometrinė informacija. Tai gana neseniai atsiradęs būdas, naudojamas žemės topografijos duomenims užrašyti, kuris Lietuvoje dar tik pradedamas naudoti. Dėl to naudinga ištirti šio metodo patikimumą, palyginant su įprastais duomenų surinkimo metodais (GPS), ir įvertinti šio metodo panaudojimo galimybes. Darbe nagrinėjama nuotolinių tyrimų metodais (LIDAR) gautų duomenų patikimumo problema. Tyrimo tikslas – nustatyti įvairiais metodais gautų reljefo aukščių duomenų patikimumą, analizuojant Riešės upelio baseino reljefą. Tyrimo eigoje buvo surinkti įvairiais metodais gauti Riešės upelio baseino reljefo duomenys; atlikti natūriniai matavimai pasirinktuose kontroliniuose ploteliuose, naudojantis geodeziniais instrumentais; pagal nuotolinių tyrimų gautus rezultatus sudarytas skaitmeninis reljefo modelis ir įvertintas jų tikslumas. Darbe palyginus natūrinių matavimų ir nuotolinių tyrimų metodais gautus rezultatus įrodyta, jog nuotoliniais tyrimų metodais gauti duomenys yra patikimi ir juos galima naudoti baseino tūriui ir plotui skaičiuoti. / LIDAR terrain laser scanning technique is increasingly used in digital terrain model creation. This method provides dense uneven three-dimensional scatter geometric and radiometric information that simulates objects on earth’s surface. This is a relatively recent method used to record topographic data of the land. One of the key issues still associated with remote sensing methods is its reliability, which is why it is relevant to analyze and evaluate this aspect. This thesis aims at evaluating LIDAR data reliability, comparing them with data obtained by field measurements carried out at selected control areas using geodesic instruments. Riešės river basin area was selected as an object for the study and its elevation data have been investigated in the research. It was concluded that LIDAR data are reliable and can be used for the basin volume calculation. However, the size of the grid should be selected according to terrain relief.