IEEE Transactions on Pattern Analysis and Machine Intelligence

Digital terrain representation. Data Acquisition Methodology. Terrain Surface Modeling (Reconstruction). Algorithms for Triangular Irregular Network Formation. Interpolation Methods. Data Quality Control. Mathematical Models for DTM Accuracy.Multi-Scale Representation of Digital Elevation Models. DTM Data Management. Contouring from DTM. DTM-Based Terrain Analysis (DTM Interpretation). Visualization of DTM Surface. Applications. Integration with GIS. Index.

Digital Terrain Modeling: Principles and Methodology

This paper provides a review of ground-based SAR (GBSAR) interferometry for deformation measurement. In the first part of the paper the fundamentals of this technique are provided. Then the main data processing and analysis stages needed to estimate deformations starting from the GBSAR observations are described. This section introduces the two types of GBSAR acquisition modes, i.e., continuous and discontinuous GBSAR, and reviews the different GBSAR processing and analysis methods published in the literature. This is followed by a discussion of the specific technical aspects of GBSAR deformation measurement. A section then summarizes the pros and cons of GBSAR for deformation monitoring. The last part of the paper includes two reviews: one concerning the GBSAR systems described in the literature, including non-strictly SAR systems and a second one addresses the main GBSAR applications.

A review of ground-based SAR interferometry for deformation measurement

The power spectra of many geophysical phenomena are well approximated by a power-law dependence on frequency or wavenumber. I derive a simple expression for the root-mean square variability of a process with such a spectrum over an interval of time or space. The resulting expression yields the power-law time dependence characteristic of fractal processes, but can be generalized to give the temporal variability for more general spectral behaviors. The method is applied to spectra of crustal strain (to show what size of strain events can be detected over periods of months to seconds) and of sea level (to show the difficulty of extracting long-term rates from short records).

The time-domain behavior of power-law noises. [of many geophysical phenomena]

Paroxysmal dome explosion during the Merapi 2010 eruption: Processes and facies relationships of associated high-energy pyroclastic density currents

Abstract One fundamental component of early warning systems for natural hazards is displacement monitoring. Spaceborne SAR Interferometry has proven to be a powerful remote sensing tool for this task. Lately new ground-based SAR instruments are available. Their application field is wide and they combine high resolution and accuracy with the classical benefits of remote sensing techniques. Here, the principles of the microwave interferometer IBIS are presented, as well as its advantages and disadvantages compared to common monitoring techniques. IBIS can be operated in two modes: IBIS-S is a microwave interferometer capable of high frequency displacement monitoring of buildings and structures (up to 200 Hz); IBIS-L is a ground-based SAR for long-term displacement monitoring of buildings and natural phenomena as landslides, glaciers, etc. Exemplary three applications are presented: the use of IBIS-S for dynamic monitoring of a chimney; the use of IBIS-L for displacement monitoring in an active quarry and the long-term operation of IBIS-L as part of a “Volcano Fast Response System” (VFRS) on an active volcano.

Monitoring of displacements with ground-based microwave interferometry: IBIS-S and IBIS-L

https://hal.archives-ouvertes.fr/hal-00615321/document

Digital elevation model with the ground-based SAR IBIS-L as basis for volcanic deformation monitoring

. The accuracy of 4 Digital Elevation Models (SRTM30, GTOPO30, SRTM3 and local DEM produced from aerial photogrammetric images) for the volcanoes Merapi and Merbabu in Java, Indonesia is investigated by comparison with 443 GPS ground control points. The study confirms the high accuracy of SRTM3 and SRTM30, even if the a priori defined 90% confidence level of 16 m for the SRTM3 is not always achieved in this mountainous region. Accuracy of SRTM30, GTOPO30 and SRTM3 is mainly dependent on the altitude itself and the slopes' inclinations, whereas the photogrammetric DEM exhibits constant accuracy over a wide range of altitudes and slopes. For SRTM3 and SRTM30 a statistically significant correlation between heights and aspects of the slopes is also found. Accuracy of DEMs which are generated by interpolation on a finer grid does not change significantly. Smoothing of DEMs on a coarser grid, however, decreases accuracy. The decrease in accuracy is again dependent on altitude and slope inclination. The comparison of SRTM30 with GTOPO30 exhibits a significant improvement of SRTM30 data.

/pdf/validation-of-digital-elevation-models-around-merapi-volcano-1yyf3nrwri.pdf

Validation of Digital Elevation Models around Merapi Volcano, Java, Indonesia

Digital Elevation Models for Mount Merapi

In Sevres the fifth International Absolute Gravimeter Intercomparison was conducted in November 1997. In order to support the absolute measurements, the BGI Working Group 8: Relative Networks at Absolute Gravimeter Comparison ICAG97 conducted a relative gravimeter campaign as well. Twelve LaCoste and Romberg and one Scintrex gravimeters measured the connections between absolute points and vertical gravity gradients at each point. In addition the calibration baseline installed in 1994 was re-measured as well to check or provide calibration factors for all gravimeters. The results show that the accuracy for single instruments is in the range of 3 to 8 μGal 1 for a gravity difference, for both the Scintrex and the LaCoste gravimeters. The campaign was also used to intercompare different ways of calibrating the gravimeter electrostatic feedback systems. The calibration platform of BKG, Frankfurt, was installed in Sevres and the results can be compared to that of the calibration line. This paper gives results for the 1997 campaign.

/pdf/results-of-relative-gravimeter-measurements-at-the-icag97-1nfowjey4w.pdf

G. Läufer

Papers

Monitoring of displacements with ground-based microwave interferometry: IBIS-S and IBIS-L

Digital elevation model with the ground-based SAR IBIS-L as basis for volcanic deformation monitoring

Validation of Digital Elevation Models around Merapi Volcano, Java, Indonesia

Digital Elevation Models for Mount Merapi

Results of relative gravimeter measurements at the ICAG97 Intercomparison