scholarly journals A note on the polynomial surface fitting method for estimation of winds at different isobaric levels using the observed wind at 850 hPa level

MAUSAM ◽  
2021 ◽  
Vol 43 (3) ◽  
pp. 307-310
Author(s):  
S. N. BAVADEKAR ◽  
R. M. KHALADKAR
Keyword(s):  
Surface Fitting ◽  
Limited Area ◽  
Degree Polynomial ◽  
Fitting Method ◽  
Polynomial Surface

A third degree polynomial surface fitting technique is adopted to compute the winds at different isobaric levels for the limited area domain from 35°E to 140°E and 30° S to 40oN for the month of June. The polynomial surfaces are fitted to the ratios of the monthly mean winds at different isobaric levels with the 850 hPa winds. The surfaces are fitted to the II and v components of the winds separately. The winds for the level are then reconstructed using the computed coefficients and observed wind at 850 hPa. The results of the technique are presented and discussed in the paper.  

Modeling landslide failure surfaces by polynomial surface fitting

Geomorphology ◽  
2020 ◽  
Vol 368 ◽  
pp. 107358 ◽  
Author(s):  
Chenxiao Tang ◽  
Jing Tang ◽  
Cees J. van Westen ◽  
Jiannan Han ◽  
Olga Mavrouli ◽  
...  
Keyword(s):  
Surface Fitting ◽  
Polynomial Surface

Research into the Model of GNSS Leveling Polynomial Surface Fitting Based on MATLAB

2011 ◽  
Vol 90-93 ◽  
pp. 2907-2912
Author(s):  
Yu Sheng Gong ◽  
Qian Han ◽  
Li Ping Zhang
Keyword(s):  
Least Squares ◽  
Robust Estimation ◽  
Automatic Processing ◽  
Surface Fitting ◽  
Normal Height ◽  
Distortion Model ◽  
Whole Process ◽  
Gross Error ◽  
Geodetic Height ◽  
Polynomial Surface

To make full use of geodetic height results measured by GNSS and improve the accuracy that GNSS geodetic height convert to normal height, method of polynomial surface fitting has been selected in this article to research into fitting of the elevation. In the first place, for least squares estimation do not have the ability of resisting gross error, robust estimation is introduced to data preprocessing, which has solve the problem of distortion model effectively and then combines with specific engineering to make comparison and to analyze accuracy of polynomial surface fitting data of different orders. MATLAB has been used in programming design in the whole process, which has realized automatic processing of data.

Estimation and Display of Triangular Mesh Curvature in Reverse Engineering

2010 ◽  
Vol 136 ◽  
pp. 95-102
Author(s):  
Hui Cun Shen ◽  
J.J. Nie ◽  
W.S. Zong ◽  
J. Wang ◽  
B.G. Yang
Keyword(s):  
Reverse Engineering ◽  
Surface Fitting ◽  
Triangular Mesh ◽  
Surface Curvature ◽  
Estimation Methods ◽  
Quadric Surface ◽  
Fitting Method ◽  
Curvature Estimation ◽  
Curvature Group ◽  
Paraboloid Surface

The estimation of triangular mesh curvature is implemented by establishing local quadric surface at vertexes of mesh. Deduction course of quadric surface curvature calculation is presented. Errors and complexity of two curvature estimation methods, which are the ecumenical quadric surface fitting method and the quadric paraboloid surface fitting method respectively, are compared. Technique for curvature group display is put forward. This technique can display features of mesh distinctly, even though the curvature values of mesh distribute non-uniformly in their variety range.

scholarly journals Weight-Bearing 3D Foot Model Reconstruction From Standing Radiographs Using Deformable Surface Fitting Method

2016 ◽  
Vol 1 (1) ◽  
pp. 2473011416S0032
Author(s):  
Sang Gyo Seo ◽  
Jaeil Kim ◽  
Chang Hyun Ryu ◽  
Eo Jin Kim ◽  
Doojae Lee ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Surface Fitting ◽  
Model Reconstruction ◽  
Deformable Surface ◽  
Fitting Method ◽  
Foot Model

Reweighting method for polynomial surface fitting

1990 ◽  
Author(s):  
Hengren Xia ◽  
Jeffrey D. MacQueen ◽  
Jeremy J. Zimmerman
Keyword(s):  
Surface Fitting ◽  
Polynomial Surface

Robust polynomial fitting method for regional gravity estimation

Geophysics ◽  
1991 ◽  
Vol 56 (1) ◽  
pp. 80-89 ◽  
Author(s):  
J. F. Beltrão ◽  
J. B. C. Silva ◽  
J. C. Costa
Keyword(s):  
Gravity Data ◽  
Crustal Thickening ◽  
Polynomial Fitting ◽  
Shallow Subsurface ◽  
Residual Field ◽  
Fitting Method ◽  
Definition Of ◽  
Regional Gravity ◽  
Lower Crustal ◽  
Polynomial Surface

Standard polynomial fitting methods are inconsistent in their formulation. The regional field is approximated by a polynomial fitted to the observed field. As a result, in addition to the nonuniqueness in the definition of the regional field, the fitted polynomial is strongly influenced by the residual field (observed field minus regional field). We present a regional‐residual separation method for gravity data which uses a robust procedure to determine the coefficients of a polynomial fitted to the observations. Under the hypothesis that the regional can be modeled correctly by the polynomial surface, the proposed method minimizes the influence of the residual field in the fitted surface. The proposed method was applied to real gravity data from Ceará state, Brazil, and produced information on zones of possible crustal thickening and the occurrence of lower‐crustal granulitic rocks thrust into the shallow subsurface.

scholarly journals APPLICATION OF MULTI-FACETED FUNCTION MODEL BASED ON VONDRAK FILTER OPTIMIZATION IN UAV AERIAL IMAGE HEIGHT CORRECTION

2020 ◽  
Vol XLII-3/W10 ◽  
pp. 1313-1317
Author(s):  
F. Zhou ◽  
L. Pu ◽  
S. H. Tang ◽  
Y. F. Yang
Keyword(s):  
High Precision ◽  
Surface Fitting ◽  
Aerial Image ◽  
Experimental Comparison ◽  
Cubic Surface ◽  
Aerial Photogrammetry ◽  
Function Fitting ◽  
Fitting Method ◽  
Elevation Correction ◽  
Vondrak Filter

Abstract. With the rapid development of drone technology and digital camera technology, the method of obtaining high-precision coordinates based on UAV aerial photogrammetry technology is popular. The plane coordinate accuracy of the aerial image of the drone has been able to meet the needs of practical applications, but the elevation accuracy is generally low. Aiming at the low elevation accuracy of UAV aerial photogrammetry, a multi-face function fitting method based on Vondrak filter optimization was proposed. The improved fitting model was used to obtain the elevation correction value of the aerial image, thereby obtaining high-precision image elevation data. In this paper, based on the traditional multi-face function fitting method, some known points were used to model and find the difference between the measured elevation value and the measured elevation. The Vondrak filter was used to smooth the fitting result. Finally, a small number of known elevation points were used for checking, so that the obtained elevation was compared with the actual elevation. The experimental comparison showed that the improved multi-face function fitting method used Vondrak filter was improved by 34.76% compared with the quadric surface fitting, and improved by 14.48% compared with the optimized cubic surface fitting method. Research shows that the multi-faceted function method based on Vondrak filtering is superior to the traditional elevation correction method. The experiment verifies the effectiveness and feasibility of the improved method, and provides some reference value for the research of aerial image elevation correction model.

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