International cooperation and technology transfer

Fras, Mojca Kosmatin

Bibliographic data

Monograph

Persistent identifier:: 856490555

Author:: Fras, Mojca Kosmatin

Title:: International cooperation and technology transfer

Sub title:: Ljubljana, Slovenia, February 2 - 5, 2000 : proceedings of the workshop

Scope:: VI, 163 Seiten

Year of publication:: 2000

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856490555

Illustration:: Illustrationen, Diagramme

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: DATA INTEGRATION FOR THE DTM PRODUCTION. Tomaz Podobnikar Dr. Zoran Stancic Kristof Ostir

Document type:: Monograph

Structure type:: Chapter

134 DATA INTEGRATION FOR THE DTM PRODUCTION Tomaz Podobnikar Dr. Zoran Stancic Kristof Ostir Scientific Research Centre of the Slovenian Academy of Sciences and Arts Gosposka ul. 13 SI-1000 Ljubljana Slovenia ISPRS WG VI/3 and IV/3 meeting: Bridging the Gap, Ljubljana 2-5 February 2000 KEY WORD: digital terrain model, digital elevation model, interpolation, SAR interferometry, GIS, quality control PURPOSE: In the late 1970’s Surveying and Mapping Authority of the Republic of Slovenia produced digital elevation model (DEM) with grid size of 100 m. The DEM was intensively used for numerous cartographic, GIS and planning purposes in the past, but nowadays it does not fulfill demands due to its poor spatial resolution and height accuracy. Therefore Surveying and Mapping Authority has started activities for better DTM production. After initial stages and some case studies, the expected quality of the new DTM was not achieved. The main objective of this paper is to present and discuss the possibility of improving existent DEM of Slovenia. Many techniques are available to produce high accuracy DEM, but they are not always economical. Our strategy is to model hydrologicaly and morphologicaly correct DTM (digital terrain model) with high statistical and visual accuracy. We intend to use different approaches for modeling different physiographic regions of Slovenia. Special emphasis will be made to the integration of vector contour lines from maps, hydrographic elements and other break lines, automatically derived relief characteristic points, geodetic points, existing DEM 100, photogrametricaly captured data, SAR DEM, etc. Results from the case study using this integrated data are very promising. DTM with 25 m grid size for selected regions in Slovenia with height accuracy of approx. 1 m for predominantly flat and urban areas, approx. 4 m for the hilly areas and about 10 m for the alpine areas. 1. INTRODUCTION Spatial databases with adequate quality are essential for management of modern society demands. Morphology of relief is one of the most important characteristics of the natural environment. Digital approximation of its surface - digital terrain’s surface model - is important for numerous cartographic, GIS and planning purposes. The need for a better model resulted in many experiments, projects and expertises about the strategies of improvement and needs of new DEM/DTM (digital elevation model / digital terrain model) in last 10 years. The results of opinion pool indicated that the most of potential users would prefer to have DEM with grid between 10 and 20 m and with height accuracy between 1 and 3 m (Stanonik, 1995). Few years ago, Surveying and Mapping Authority started activities for the production DEM with 25 m resolution. After initial stages and some case studies, the expected quality of the new DEM was not achieved. Maybe the main reasons of not satisfying results in DEM / DTM production in Slovenia are the diametrically opposite demands: simplification in production methods and making large - no economical projects for production. Our approach is to integrate different available height data sources of Surveying and Mapping Authority, which have different quality. In last years more and more georeferenced databases form different sources have been available. In our case study special emphasis has been paid to the integration of vector contour lines from maps, hydrographic elements and other characteristic lines, automatically derived characteristic lines and points, geodetic points, DEM 100. We are also performing a reliable process of quality control of the model. 2. DEFINITION OF THE TERMS DEM / DTM Definition of DTM / DEM is not an easy task. In the literature we can find many definitions, from simple to complex. The reasons of such disorder probably lies in different techniques of modeling, representation, recording and fields of interest of relief data applications. In definition we consider the Earth surface as a continuous (indiscrete) phenomena, which is attempted to be represented with function(s). Such functions could be continuous mathematical or statistical. Digital terrain model can be understood as “digital description of the Earth’s surface”. It does not include only representation of the relief itself but also its description, as slope, aspect, contour lines, break lines, peaks, and the other characteristic points. The following components are needed for complete definition of the DTM (Martinoni and Bernhard, 1998): data elements, .structural information, continuous functions, quality information, methods for implicit functions analyses. Data elements may be understood as support to the model. They explicitly describe elevation with points, lines or areas in the belonging coordinate system. Data elements are often registered as grid or included in TIN.

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