Articolele autorului Lucian Dragut
Link la profilul stiintific al lui Lucian Dragut

Transformation (normalization) of slope gradient and surface curvatures, automated for statistical analyses from DEMs

Automated procedures are developed to alleviate long tails in frequency distributions of morphometric variables. They minimize the skewness of slope gradient frequency distributions, and modify the kurtosis of profile and plan curvature distributions towards that of the Gaussian (normal) model. Box-Cox (for slope) and arctangent (for curvature) transformations are tested on nine digital elevation models (DEMs) of varying origin and resolution, and

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Comparing supervised and unsupervised multiresolution segmentation approaches for extracting buildings from very high resolution imagery

Although multiresolution segmentation (MRS) is a powerful technique for dealing with very high resolution imagery, some of the image objects that it generates do not match the geometries of the target objects, which reduces the classification accuracy. MRS can, however, be guided to produce results that approach the desired object geometry using either supervised or unsupervised approaches. Although some studies have suggested that a supervised approach

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Automated parameterisation for multi-scale image segmentation on multiple layers

We introduce a new automated approach to parameterising multi-scale image segmentation of multiple layers, and we implemented it as a generic tool for the eCognitionŸ software. This approach relies on the potential of the local variance (LV) to detect scale transitions in geospatial data. The tool detects the number of layers added to a project and segments them iteratively with a multiresolution segmentation algorithm in a bottom-up approach, where

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Is the distribution pattern of the stone crayfish in the Carpathians related to karstic refugia from Pleistocene glaciations?

The stone crayfish, Austropotamobius torrentium, is one of the oldest freshwater crayfish species in Europe. Most Carpathian populations are in Romania, with a distribution clustered in 2 compact metapopulations in the western part of the country. Our goal was to understand if this pattern is the result of a coincidence or a complex set of restrictive circumstances. Romania is an ideal place to analyze crayfish distributions because they have not

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Quantitative evaluation of variations in rule-based classifications of land cover in urban neighbourhoods using WorldView-2 imagery

The increasing availability of high resolution imagery has triggered the need for automated image analysis techniques, with reduced human intervention and reproducible analysis procedures. The knowledge gained in the past might be of use to achieving this goal, if systematically organized into libraries which would guide the image analysis procedure. In this study we aimed at evaluating the variability of digital classifications carried out by three

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Land-surface segmentation to delineate elementary forms from Digital Elevation Models

In this paper, we introduce an algorithm to delineate elementary forms on Digital Elevation Models (DEMs). Elementary forms are defined by constant values of fundamental morphometric properties and limited by discontinuities of these properties. A multiresolution segmentation technique was customized to partition the layers of altitude derivatives into homogeneous divisions through a self-scalable procedure, which reveals the pattern encoded within

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Land-Surface Segmentation as sampling framework for soil mapping

Current sampling methods require a large number of samples to account for spatial variation of environmental covariates, which often conflicts the available financial resources. Thus, efficient sampling strategies are desirable. The aim of this study was to evaluate the potential of land-surface segmentation in stratifying a landscape into homogeneous areas, which can be used as support in optimizing soil sampling. The experiments were carried out

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Variations in landform definition: a quantitative assessment of differences between five maps of glacial cirques in the Þarcu Mountains (Southern Carpathians, Romania)

Geomorphological mapping is an important tool in geomorphology and related disciplines, yet it depends on the expertise and experience of the practitioner. The reliability of the technique and its products has not been subject to sufficient quantitative evaluation. In this study, we evaluated the magnitudes of differences in mapping glacial cirques between five maps in a mountainous area in the Southern Carpathians in Romania and attempted to identify

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An Object-Based Workflow to Extract Landforms at Multiple Scales From Two Distinct Data Types

Landform mapping is more important than ever before, yet the automatic recognition of specific landforms remains difficult. Object-based image analysis (OBIA) steps out as one of the most promising techniques for tackling this issue. Using the OBIA approach, in this study, a multiscale mapping workflow is developed and applied to two different input data sets: aerial photographs and digital elevation models. Optical data are used for gully mapping

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Geomorphometry 2013: Conference + Workshops

October 16-20, 2013 Nanjing, China http://www.geomorphometry.org/2013

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