The effects of JPEG compression on automated DTM extraction via the approach of feature-based matching are investigated. JPEG lossy compression involves a truncation of higher spatial frequency data, a process which influences the accuracy of computation of grey-value gradients in the feature determination phases of image matching. Resulting accuracy effects on DTM heights obtained via the MATC...

This paper describes how CyberCity Modeler is used in order to extract both the terrain and the man-made remains of a pre-hispanic site in Central Mexico, a task for which it was not intended originally. We take an oriented aerial stereomodel and measure the point clouds of all architectural structures and the Digital Terrain Model points in manual mode. The structuring of the objects is then p...

The development of rapid prototyping has evolved from the crude milled models to the laser polymerised stereolithographic models of excellent accuracy. The technology was advanced further with the recent introduction of fused deposition modelling and the 3-dimensional ink-jet printing technique in stereo-model fabrication. The concept of using a 3dimensional model in planning the operation has ...

Terrain skeleton lines, among the most significant elements of topographical maps, are the valley lines that connect the deepest points of valleys, and the ridge lines that connect the highest points of ridges. In order to obtain correct and enough information about land forms from a topographical map, skeleton lines have to be considered and portrayed together with contours. Their extraction h...

In almost all areas of our society there is an increasing need for well maintained and frequently revised digital map databases. Maintenance and revision of geo-spatial databases can be divided into 3 steps: Change detection, classification of changes and registration and updating of the database. Traditionally, three different methods have been used for change detection: field inspections; man...

In order to analyze the slope stability in open-pit mines, the structural parameters of rock mass such as persistence and spatial orientation of discontinuities are characterized through field surveys, which involve spending high costs and times as well as posing high risks of rock toppling and rock fall. In the present work, a new application of terrestrial digital photogrammetry is introduced...

The Topographical Survey Division of the Surveys and Mapping Branch, Energy, Mines and Resources, Canada, employs dense digital elevation model (DEM) data for the production of hypsographic overlays for conventional and orthophoto maps. The Gestalt Photomapper (GPM II/3), installed as a production system since summer of 1977, uses computer controlled electronic scanning and image correlation te...

Background and Purpose: The main goal of this paper was to highlight the importance of colour infrared (CIR) aerial photographs for efficient inventory, monitoring and predicting the health status of forests in changed site conditions. CIR aerial photographs from two aerial surveys conducted in 1989 and 2008 were used to identify and analyze the damage in lowland pedunculated oak (Quercus robur...

Features of Spatial Snag Distribution in a Beech-Fir Forest With the participation of about 65% in the total growing stock of conifers, silver fir is the most important andthe best represented conifer species in Croatia. The increasing share of sanitary felling in the annual felling plansdemands that special attention be paid to the health status of fir forests and the quantity of unpla...