Digital elevation model (DEM) is one of the most important datasets for the greater part of spatial-based studies and research. Generally, a high quality DEM could be used as all-purpose dataset, but unfortunately its production could be very expensive. If we know a nature of application that applies DEM, if our demands for the final result are clear, and if provider of DEM gives enough clear i...

Digital Elevation Model (DEM) is the core data for three-dimensional visualization and geographical spatial analysis. With the implementation of Digital Earth, the amount of various DEM data is rapidly expanding. In order to compress DEM data, researchers ever put forward two kinds of DEM compression methods: Generic entropy encoding compression; Converting grid DEM to TIN DEM [1][2]. In recent...

This paper reports experiments carried out for automated extraction of a digital elevation model (DEM) from satellite images. In particular, this paper focuses on DEM extraction from dense urban areas where there are occlusions, shadow and height discontinuities. These properties have been known to create many problems in stereo matching and for automated DEM extraction. Using satellite images ...

An approach to DEM fusion was developed to improve the overall accuracy of DEMs and applied to two public products: Shuttle Radar Topographic Mission (SRTM) DEM and Advanced Spaceborne Thermal Emission and Reflection (ASTER) DEM. The relative ASTER DEM was co-registered to the SRTM coordinates and converted to the near absolute DEM by shifting the histogram to the average elevation of the SRTM ...

The Permanent Scatterers (PS) technique is a powerful operational tool that exploits long series of SAR data for monitoring ground deformations with millimetre accuracy on a high spatial density grid of point-wise targets. The technique has been applied successfully to a number of applications from subsidence and volcano monitoring to slow-landslide detection. Aim of this work is to analyse the...

Using a combination of the Hopkins Verbal Learning Test (HVLT) and the Mini-Mental State Examination (MMSE), we investigated the prevalence of possible dementia (DEM) in community-dwelling elderly in Shanghai. Subsequently, we investigated significant risk factors for DEM and generated a DEM self-checklist for early DEM detection and case management. We found that among a total of 521 participa...

The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) is one of the most complete and frequently used global-scale DEM products in various applications. However, previous studies have shown that the SRTM DEM is systematically higher than the actual land surface in vegetated mountain areas. The objective of this study is to propose a procedure to calibrate the SRTM DEM over l...