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Generation of a ground-level DEM in a dense equatorial forest zone by merging airborne laser data and a top-of-canopy DEM

Abstract : This paper describes the generation of a ground-level digital elevation model (DEM) by merging airborne elevation data and a top-of-canopy DEM. The study area is located in a dense equatorial forest setting in French Guiana, for which it is assumed that no topographic map is available. The data used consist of airborne laser data distributed along flight lines spaced at 500 m (with a data interval every 7 m) and a top-of-canopy DEM obtained by merging a stereoradargrammetric DEM with airborne laser data. Generation of the ground-level DEM involves the following steps: (i) selecting ground points from the airborne data and deducing a pseudo canopy height for these points, (ii) characterizing the canopy height from a statistical and geostatistical standpoint, (iii) kriging the canopy height and subtracting the resulting model from the top-of-canopy DEM to obtain a DEM corresponding to a ground-level DEM, and (iv) validation. Validation consists of comparing the results with topographic maps and a local heliborne DEM and studying the relationship between the configuration of the airborne trials, in terms of flight-line spacing, and accuracy of the resulting kriged DEM. The results show that the accuracy of the kriged ground-level DEM is significantly better than that of the initial radargrammetric DEM. The standard deviation of elevation errors is reduced from 21.2 to 11.9 m or from 25.3 to 11.1 m, depending on the validation source adopted (French National Geographic Institute spot heights and local heliborne DEM, respectively). In addition, the relationship between flight-line spacing and accuracy of the resulting kriged DEM helps estimate what flightline spacing is needed to obtain a given accuracy
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https://hal-brgm.archives-ouvertes.fr/hal-00614832
Contributor : Bernard Bourgine <>
Submitted on : Tuesday, August 16, 2011 - 5:57:11 PM
Last modification on : Thursday, August 6, 2020 - 9:46:03 AM

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Bernard Bourgine, Nicolas Baghdadi, Steven Hosford, Philippe Daniels. Generation of a ground-level DEM in a dense equatorial forest zone by merging airborne laser data and a top-of-canopy DEM. Canadian Journal of Remote Sensing, Canadian Aeronautics, 2004, 30 (6), pp.613-626. ⟨10.5589/m04-049⟩. ⟨hal-00614832⟩

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