Institut Cartografic De Catalunya Research Articles

Assessment of airborne LIDAR for snowpack depth modeling

The Institut Geologic de Catalunya (IGC) and the Institut Cartografic de Catalunya (ICC) have begun a joint project to model snowpack depth distribution in the Nuria valley (a 38 km 2 basin located in the Eastern Pyrenees) in order to evaluate water reserves in mountain watersheds . The evaluation was based on a remote sensing airborne LIDAR survey and validated with field-work calculations. Previous studies have applied geostatistical techniques to extrapolate sparse point data obtained from costly field-work campaigns. Despite being a recently developed technique, LIDAR has become a useful method in snow sciences as it produces dense point data and covers wide areas. The new methodology presented here combines LIDAR data with field-work, the use of geographical information systems (GIS) and the stepwise regression tree (SRT), as an extrapolation technique. These methods have allowed us to map snowpack depth distribution in high spatial resolution. Extrapolation was necessary because raw LIDAR data was only obtained from part of the study area in order to minimise costs. Promising results show high correlation between LIDAR data and field data, validating the use of airborne laser altimetry to estimate snow depth. Moreover, differences of total snow volume calculated from modeled snowpack distribution and total volume from LIDAR data differ by only 1 %.

Single-Pass Bistatic SAR Interferometry Using Fixed-Receiver Configurations: Theory and Experimental Validation

In this paper, bistatic interferometry using fixed-receiver configurations is addressed both theoretically and experimentally. The analytical expressions for interferometric phase and height sensitivity are derived, and a full interferometric processing chain for digital elevation model (DEM) generation is presented. The derived expressions are general, and they can be applied to two possible acquisition geometries: <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">backscattering</i> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">forward scattering</i> . The theoretical developments are complemented with experimental results done with the bistatic receiver Synthetic Aperture radar Bistatic Receiver for INterferometric Applications. The obtained DEMs are compared with a DEM from the Shuttle Radar Topography Mission and a digital terrain model from the Institut Cartografic de Catalunya. The comparison allows one to validate the results and demonstrate to which particular features of the scene that the bistatic radar is sensitive.

The 4th ICA Mountain Cartography Workshop, Vall de Núria, Catalonia, Spain (30 September–2 October 2004)

The International Cartographic Association Commission on Mountain Cartography held its fourth Mountain Cartography Workshop in the Vall de Nuria of the Catalan Pyrenees. This location is situated in the north of Catalonia, at 2000m altitude, and is surrounded by mountains that reach nearly 3000m. The valley can be reached only via a silent cog railway and has a wealth of history and tradition, documented since 1087. It was a perfect meeting place to discuss and confer about current issues in the field of mountain cartography. The workshop, held biennially as part of the activities of the commission, covered many topics related to mountain cartography, such as avalanche and glacier mapping, relief presentation, tourist mapping, data capture, photogrammetry, remote sensing, geovisualization, and multimedia. The 40 participants from Austria, Canada, France, Germany, Poland, Romania, Slovenia, Spain, Switzerland, and the United States spent three fruitful days together. The workshop was sponsored and perfectly organized by the Institut Cartografic de Catalunya (ICC) – special thanks go to Maria Pla and Blanca Baella – and covered the following topics: