Digital photogrammetry and kinematic GPS applied to the monitoring of Vulcano Island, Aeolian Arc, Italy

Abstract

Digital photogrammetry and kinematic global positioning system (GPS) techniques are investigated and compared over a volcanic area as operational approaches to map the topography and monitor surface displacements. The use of terrestrial and airborne GPS to support the photogrammetric survey allowed for operational and processing time reduction without loss of accuracy. A digital elevation model (DEM) is obtained from the processing of the high‐resolution digital imagery survey, which provides detailed information over a large area. The internal accuracy of the derived DEM has been verified by the comparison of two sets of data obtained from imagery acquired in different epochs; the observed root‐mean‐square error of residuals ranges from a few centimetres to 15 cm depending on the morphological features. Kinematic and pseudo‐kinematic GPS surveys are performed to derive accurate 3‐D coordinates at monumented benchmarks and accurate elevation profiles along footpaths. The average repeatability of the GPS measurements on benchmarks is 1 cm for measurement durations of 2–3 min. The standard deviation of interpolated vertical coordinates obtained at the crossings of kinematic GPS profiles is 4.3 cm. The high quality of these GPS coordinates justifies their use also for the validation of the photogrammetric DEM. A comparison of 6000 common points provides a standard deviation of residuals of 18 cm. The results show that the deformation pattern of a volcanic area can be rapidly and accurately monitored even in the absence of geodetic benchmarks. The integration of aerial photogrammetry with GPS kinematic surveys may be considered as an optimal approach for deriving high‐resolution mapping products to be used in support of studies of volcanic dynamics.

Remote Sensing and Geodetic Measurements for Volcanic Slope Monitoring: Surface Variations Measured at Northern Flank of La Fossa Cone (Vulcano Island, Italy)

“…The 1996 survey of the entire island, performed with a Leica Wild RC20 film camera, consisted of a block formed by 4 strips, including 36 photos at 1:10,000 scale [2]. The camera positions were determined by means of kinematic GPS measurements (with the base station on the ground), leading to a preliminary registration into the WGS-84 reference frame, allowing the reduction of the number of ground control points [37].…”

“…The geomorphological changes of areas affected by crustal deformation, eruptive events, gravitative instabilities, landslide and glacier evolution and other phenomena can be detected and quantified by means of the comparison between multi-temporal models providing a space-time description of geophysical processes [1][2][3][4][5][6]. Several techniques, including global positioning system (GPS) static and kinematic methodology [7], digital aerial and terrestrial photogrammetry [8], airborne and terrestrial laser scanning [9], satellite-based and ground-based interferometric radar [10] and optical satellite imagery systems [11], are suitable surveying methods that provide appropriate spatial resolution.…”

High‐resolution, digital photogrammetric mapping: A tool for Earth science

“…Based on the use of a significant number of GCP surveyed by geodetic methods in the field, conventional aerial surveys applying photo grammetric film cameras have been used to provide surface models with decimeter, and under certain conditions, even centimeter point accuracy for active volcanoes [Zlotnicki et al, \990;Achilli et al, 1998]. Here,GCP have been used to determine the exterior orientation of the camera indirectlyA reduction of GCP needs on volcanic terrain has recently been experimented with by Baldi et al [2000], who also assess the dependency of accuracy on the number of GCP Because of ongoing ground deformation in active volcanic areas, measuring GCP in the field is generally required for each image flight. Therefore, the overall efforts for the technique have been considered very costly for monitoring purposes, and its application has been limited to small areas, in spite of the increased efficiency provided by digital photogrammetric process ing compared to analytical photogrammetry Moreover, the location of the GCP is bound to the target area, which can make it impossible to achieve a required degree of accuracy due to non-accessibility and time constraints associat ed with eruptive events.…”

A geomatics data integration technique for coastal change monitoring

“…Advances in stereo-photogrammetric techniques have made aerial photography a valuable source of data for the Earth sciences (e.g. Chandler and Cooper, 1989;Baldi et al, 2000), but in coastal studies photogrammetry has generally been applied only crudely, with users being warned of the effects of tilt, scale variation and relief displacement affecting the accuracy of their measurements (Moore, 2000). The Environment Agency and local authorities in southeast England have been an exception to this, carrying out aerial surveys and profile surveying (e.g.…”