scholarly journals Comparative investigation of parallel spatial interpolation algorithms for building large-scale digital elevation models

2020 ◽  
Vol 6 ◽  
pp. e263 ◽  
Author(s):  
Jingzhi Tu ◽  
Guoxiang Yang ◽  
Pian Qi ◽  
Zengyu Ding ◽  
Gang Mei
Keyword(s):  
Computational Efficiency ◽  
Large Scale ◽  
Information Science ◽  
Digital Elevation Models ◽  
Least Square ◽  
Interpolation Algorithm ◽  
Moving Least Square ◽  
Interpolation Algorithms ◽  
Interpolation Accuracy ◽  
Digital Elevation

The building of large-scale Digital Elevation Models (DEMs) using various interpolation algorithms is one of the key issues in geographic information science. Different choices of interpolation algorithms may trigger significant differences in interpolation accuracy and computational efficiency, and a proper interpolation algorithm needs to be carefully used based on the specific characteristics of the scene of interpolation. In this paper, we comparatively investigate the performance of parallel Radial Basis Function (RBF)-based, Moving Least Square (MLS)-based, and Shepard’s interpolation algorithms for building DEMs by evaluating the influence of terrain type, raw data density, and distribution patterns on the interpolation accuracy and computational efficiency. The drawn conclusions may help select a suitable interpolation algorithm in a specific scene to build large-scale DEMs.

An Efficient Meshfree Method for Fracture Analysis of Cracks in Bi-Materials

2006 ◽  
Author(s):  
B. Nandulal ◽  
B. N. Rao ◽  
C. Lakshmana Rao
Keyword(s):  
Computational Efficiency ◽  
Basis Function ◽  
Meshfree Method ◽  
Fracture Analysis ◽  
Least Square ◽  
Moving Least Square ◽  
Linear Elastic ◽  
Moving Least Square Approximation ◽  
Material Fracture ◽  
Element Free

This paper presents an enriched meshless method based on an improved moving least-square approximation (IMLS) method for fracture analysis of cracks in homogeneous, isotropic, linear-elastic, two-dimensional bimaterial solids, subject to mixed-mode loading conditions. The method involves an element-free Galerkin formulation in conjunction with IMLS and a new enriched basis functions to capture the singularity field in linear-elastic bi-material fracture mechanics. In the IMLS method, the orthogonal function system with a weight function is used as the basis function. The IMLS has higher computational efficiency and precision than the MLS, and will not lead to an ill-conditioned system of equations. The proposed enriched basis function can be viewed as a generalized enriched basis function, which degenerates to a linear-elastic basis function when the bimaterial constant is zero. Numerical examples are presented to illustrate the computational efficiency and accuracy of the proposed method.

scholarly journals Identification of Micro-Scale Landforms of Landslides Using Precise Digital Elevation Models

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 117 ◽  
Author(s):  
František Chudý ◽  
Martina Slámová ◽  
Julián Tomaštík ◽  
Roberta Prokešová ◽  
Martin Mokroš
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Digital Elevation Models ◽  
Canopy Cover ◽  
Point Clouds ◽  
Tree Canopy ◽  
Automatic Identification ◽  
Optical Parameters ◽  
Micro Scale ◽  
Digital Elevation

An active gully-related landslide system is located in a deep valley under forest canopy cover. Generally, point clouds from forested areas have a lack of data connectivity, and optical parameters of scanning cameras lead to different densities of point clouds. Data noise or systematic errors (missing data) make the automatic identification of landforms under tree canopy problematic or impossible. We processed, analyzed, and interpreted data from a large-scale landslide survey, which were acquired by the light detection and ranging (LiDAR) technology, remotely piloted aircraft system (RPAS), and close-range photogrammetry (CRP) using the ‘Structure-from-Motion’ (SfM) method. LAStools is a highly efficient Geographic Information System (GIS) tool for point clouds pre-processing and creating precise digital elevation models (DEMs). The main landslide body and its landforms indicating the landslide activity were detected and delineated in DEM-derivatives. Identification of micro-scale landforms in precise DEMs at large scales allow the monitoring and the assessment of these active parts of landslides that are invisible in digital terrain models at smaller scales (obtained from aerial LiDAR or from RPAS) due to insufficient data density or the presence of many data gaps.

scholarly journals Improvements in large-scale drainage networks derived from digital elevation models

2006 ◽  
Vol 42 (8) ◽  
Author(s):  
Adriano Rolim Paz ◽  
Walter Collischonn ◽  
André Luiz Lopes da Silveira
Keyword(s):  
Large Scale ◽  
Digital Elevation Models ◽  
Drainage Networks ◽  
Digital Elevation

A Comparison between Moving Least-Square Method and Natural Neighbour Interpolation

2013 ◽  
Vol 739 ◽  
pp. 653-656
Author(s):  
Zhi Feng Nie ◽  
Xing Long Li ◽  
Heng Heng Wu
Keyword(s):  
Computational Efficiency ◽  
Matrix Multiplication ◽  
Least Square Method ◽  
Matrix Inversion ◽  
Least Square ◽  
Shape Functions ◽  
Computational Accuracy ◽  
Computational Stability ◽  
Moving Least Square ◽  
Order Continuous

The construction procedures of shape functions in the moving least-square method (MLS) are complicated, in which many matrix multiplication and matrix inversion are included, so that the computational efficiency is low. Moreover, the choices of some parameters are influenced by the artificial factors, and the computational stability is poor. However, the construction procedures of shape functions in natural neighbour interpolation (NNI) are based on Voronoi diagram and its dual Delaunay triangulation, computational results are only related with the locations of the discretized nodes, and the computational stability is good. In order to study the differences in the computational accuracy, the computational efficiency, and the adaptability to the fitted objects between MLS-based shape functions andC1natural neighbour interpolant, the two higher-order continuous shape functions are introduced in surface fitting.

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