The Influence of Pillar Displacements on Geodetic Measurements

This paper deals with the effects that displacements of the measuring pillar have on precise geodetic measurements. The changes in the position of the control points on the object or its surroundings can only be determined with well stabilized and stable reference points. These points are usually stabilized with measuring pillars which are not always constructed in an optimal manner. If they are placed in a dark tube with a high absorption factor, solar heating on one side of the pillar can cause the pillar to deflect considerably due to the temperature difference on the two sides of the pillar. This paper presents the influence of such a displacement, if the pillar is a survey point, orientation point, or control point. We show that even small displacement of the survey point can have important influence on all measurements and that the error in some cases significantly increases, e.g., if the standard deviations of the coordinates of the survey point are 1 mm and their covariance is assumed to be zero, the standard deviation of the distance between measured and exact position of the control point exceeds the value of 2.2 mm.

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Development and Definition of Prambanan Temple Deformation Monitoring Control Points

JGISE Journal of Geospatial Information Science and Engineering ◽

10.22146/jgise.40788 ◽

2019 ◽

Vol 1 (2) ◽

Author(s):

Rochmad Muryamto ◽

Muhammad Iqbal Taftazani ◽

Yulaikhah Yulaikhah ◽

Bambang Kun Cahyono ◽

Anindya Sricandra Prasidya

Keyword(s):

Standard Deviation ◽

Control Point ◽

Deformation Monitoring ◽

Reference Points ◽

Control Points ◽

Deformation Control ◽

Processing Strategies ◽

Geological Map ◽

Definition Of ◽

Gnss Data

Since 1991, Prambanan Temple has been recognized by UNESCO as a cultural heritage of a historic building. In its construction, the Prambanan temple was established in a labile soil structure in the sandy soil and not far from the Opak River. In the geological map of Yogyakarta, there is a fault under the Opak River landscape. This fault under the Opak River has caused an earthquake in 2006. Because of its position in disaster-prone areas, regular monitoring of the geometric aspects of Prambanan Temple is very necessary.This research aims to build a deformation monitoring control point in Prambanan Temple. Eight control points, consist of three existing points and five new points are built around Prambanan Temple. These eight control points then were measured by observing GNSS for 1x24 hours in order to define their coordinates. GNSS data processing is done using GAMIT 10.70 software with two strategies, namely (1) processing with regional binding points, in this case using IGS BAKO and JOG2 stations, and (2) processing with global binding points using IGS COCO station reference points, DARW, KARR, POHN, PIMO, DGAR, and IISC. This research yields the establishment of Prambanan temple deformation control points and their coordinates and standard deviation in two processing strategies. The smallest standard deviation in the first strategy is 0.0787 m on the Z-axis for points of PRO1 and PR03. The biggest standard deviation is 0.1218 m on the Y-axis at point of PR02. In the second strategy the smallest standard deviation is 0.0036 m on the Z-axis for points of PR01 and PR03. The biggest standard is 0.0141 m on the Y-axis at point of PR02.

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Analysis of the Effect of Different Combinations of Observation Satellites on the Resolving Accuracy of GNSS Observation Data

E3S Web of Conferences ◽

10.1051/e3sconf/202020603025 ◽

2020 ◽

Vol 206 ◽

pp. 03025

Author(s):

Junze Wang ◽

Maohua Yao ◽

Wenting Zhou ◽

Xiangping Chen

Keyword(s):

Measurement Accuracy ◽

Control Point ◽

Satellite System ◽

Base Stations ◽

Observation Data ◽

Control Points ◽

Level Control ◽

Satellite Systems ◽

Beidou Navigation Satellite System ◽

Stable Measurement

In this paper, 24 C-level control points under different terrain conditions were selected to be the testing points. The binary-satellite system (GPS+GLONASS) and the triple-satellite system with BeiDou Navigation Satellite System (BDS) (BDS+GPS+GLONASS) were adopted for static measurement; and the observation data from BeiDou Ground-based Augumentation System (GBAS) base stations in Guangxi were collected for solution. By comparing the residuals of GPS tri-dimensional baseline vectors and the internal accord accuracy of each control point under the binary and triple-satellite systems, the effect of data collected by different satellite systems under different terrain conditions on measurement accuracy was studied. According to the results, (1) the triple-satellite system with BDS showed more stable measurement accuracy; (2) in plane, the two systems were of equivalent measurement accuracy in mountainous and flat areas; in elevation, the triple-satellite system showed higher and more stable measurement accuracy.

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Design and Geodetic Adjustment of Levelling Network for Establishment of Unified Control Points in Korea

International Journal of Geoinformatics ◽

10.52939/ijg.v17i2.1755 ◽

2021 ◽

pp. 29-40

Author(s):

H.K Lee ◽

S.H. Yun ◽

J.H. Kwon ◽

J.S. Lee

Keyword(s):

Pilot Study ◽

Vertical Component ◽

Reference Points ◽

Spatial Density ◽

Control Points ◽

Network Adjustment ◽

Technical Challenge ◽

Adjustment Procedure ◽

Geodetic Control ◽

Horizontal Network

The unified control points (UCPs), the multi-dimensional geodetic reference points installed in the low elevated area, has been established in Korea for the combination of the horizontal and the vertical geodetic control. While the 1st-phase UCPs network was completed in 2011 with a spatial density of about 10km, its densification has been underway as the 2nd-phase project. The UCPs supersedes the legacy geodetic points, such as triangulation points and benchmarks (BMs) once the 2nd-phase implementation. Although the horizontal network of the UPCs can be readily realised by GNSS technology, a technical challenge of the vertical component remains to be settled due to characteristics of the geodetic levelling technique. To this end, a pilot study was conducted to design a new version of the UCPs-based levelling network and to demonstrate its effectiveness with a comparison of the legacy. In this paper, a concept of the UCPs-based levelling network is briefly addressed with some prominent examples, and details of a pilot network and its measurements is given with the network adjustment procedure. Finally, results of the adjustments are provided with an emphasis on the influence of the newly designed network in terms of accuracy, reliability and estimated heights.

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MULTIRESOLUTION CONTROL OF CURVES AND SURFACES WITH A SELF-SIMILAR MODEL

Fractals ◽

10.1142/s0218348x1000497x ◽

2010 ◽

Vol 18 (03) ◽

pp. 271-286 ◽

Cited By ~ 1

Author(s):

HOUSSAM HNAIDI ◽

ERIC GUÉRIN ◽

SAMIR AKKOUCHE

Keyword(s):

Wavelet Transform ◽

Control Point ◽

Iterated Function Systems ◽

Control Points ◽

Similar Model ◽

Surface Theory ◽

Curves And Surfaces ◽

Iterated Function ◽

Resolution Level ◽

Self Similar

This paper presents two self-similar models that allow the control of curves and surfaces. The first model is based on IFS (Iterated Function Systems) theory and the second on subdivision curve and surface theory. Both of these methods employ the detail concept as in the wavelet transform, and allow the multiresolution control of objects with control points at any resolution level.In the first model, the detail is inserted independently of control points, requiring it to be rotated when applying deformations. In contrast, the second method describes details relative to control points, allowing free control point deformations.Modeling examples of curves and surfaces are presented, showing manipulation facilities of the models.

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Smoothness of C-Bezier Curves

Volume 1: 20th Computers and Information in Engineering Conference ◽

10.1115/detc2000/cie-14658 ◽

2000 ◽

Author(s):

Manhong Wen ◽

Kwun-Lon Ting

Keyword(s):

Shape Control ◽

Control Point ◽

Design Procedure ◽

Design Parameters ◽

Control Points ◽

Bezier Curves ◽

Bézier Curves ◽

Point Distribution ◽

G1 Continuity ◽

G2 Continuity

Abstract This paper presents G1 and G2 continuity conditions of c-Bezier curves. It shows that the collinear condition for G1 continuity of Bezier curves is generally no longer necessary for c-Bezier curves. Such a relaxation of constraints on control points is beneficial from the structure of c-Bezier curves. By using vector weights, each control point has two extra free design parameters, which offer the probability of obtaining G1 and G2 continuity by only adjusting the weights if the control points are properly distributed. The enlargement of control point distribution region greatly simplifies the design procedure to and enhances the shape control on constructing composite curves.

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G1 Continuity of C-Bezier Rectangular Surfaces

Volume 1: 20th Computers and Information in Engineering Conference ◽

10.1115/detc2000/cie-14657 ◽

2000 ◽

Author(s):

Manhong Wen ◽

Kwun-Lon Ting

Keyword(s):

Control Point ◽

Sufficient Conditions ◽

Necessary And Sufficient Conditions ◽

Design Parameters ◽

Control Points ◽

Bézier Surfaces ◽

G1 Continuity ◽

Bezier Surfaces ◽

Necessary And Sufficient

Abstract This paper probes G1 continuity between two adjacent c-Bezier rectangular patches. The necessary and sufficient conditions are derived. It shows that the coplanar condition for G1 continuity of two adjacent Bezier patches is not necessary for c-Bezier patches. Such a relaxation of constraints on control points is beneficial from vector weights of c-Bezier surfaces, which leads to two extra free design parameters for each control point. C-Bezier surfaces offer the possibility of obtaining G1 continuity by just adjusting the weights, which greatly simplifies the design to construct composite surfaces.

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Research on the Characteristics of Infrared Radiation Spectra at Zigong Acupoint within Menstrual Cycle of Healthy Female

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2019/9568324 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Meng Qin ◽

Si-qi Ma ◽

Zhi-ming Huang ◽

Xue-yong Shen ◽

Jian-zi Wei

Keyword(s):

Menstrual Cycle ◽

Radiation Intensity ◽

Infrared Radiation ◽

Statistical Difference ◽

Radiation Spectrum ◽

Control Point ◽

Control Points ◽

Total Radiation ◽

Healthy Female ◽

The Right

The purpose of this study was to observe the characteristics of infrared radiation spectrum of Zigong acupoint (EX-CA1) within the menstrual cycle of healthy female. We used highly sensitive infrared radiation spectrum detection system and phase-locked amplification technology to detect and analyse the infrared radiation spectrum from 1.5μm to 18μm of 32 healthy female before, during, and after menstruation at EX-CA1 and control points. The results showed that the total radiation intensity of left EX-CA1 was significantly higher than that of left control point (P<0.05) at the whole menstrual cycle, and the difference between right EX-CA1 and right control points was statistically significant before and after menstruation (P<0.05), no statistical difference during menstruation. Previous studies found that the radiation near 15μm was correlated with glucose metabolism. The results of this study showed that there were statistical differences in 10 wavelengths between left EX-CA1 and left control point from 14μm to 18μm, and there were statistical differences in 3 wavelengths on the right side (P<0.05). The left side is more prominent than the right side. The infrared radiation intensity of EX-CA1 decreased gradually with the change of cycle rhythm within menstrual cycle, but there was no statistical difference in this trend. There was no statistical difference in total radiation intensity between the right and left side of EX-CA1. Compared with the control points, the number of different wavelengths between left EX-CA1 and left control point during menstruation was significantly larger than that between right EX-CA1 and right control point (P<0.001). The results indicated that the energy of EX-CA1 was higher than control points. There was no difference in the radiation intensity between the right and left sides of EX-CA1 but there was acupoint laterality compared with nonacupoints. There was no significant rhythmic change in infrared radiation intensity of EX-CA1 during the menstrual cycle.

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Evaluation of Photogrammetry and Inclusion of Control Points: Significance for Infrastructure Monitoring

Data ◽

10.3390/data4010042 ◽

2019 ◽

Vol 4 (1) ◽

pp. 42 ◽

Cited By ~ 1

Author(s):

Renee Oats ◽

Rudiger Escobar-Wolf ◽

Thomas Oommen

Keyword(s):

Laser Scanning ◽

Retaining Wall ◽

Control Point ◽

Wall Structure ◽

Control Points ◽

Point Selection ◽

Cloud Data ◽

Infrastructure Monitoring ◽

Mode Behavior ◽

The Impact

Structure from Motion (SfM)/Photogrammetry is a powerful mapping tool in extracting three-dimensional (3D) models from photographs. This method has been applied to a range of applications, including monitoring of infrastructure systems. This technique could potentially become a substitute, or at least a complement, for costlier approaches such as laser scanning for infrastructure monitoring. This study expands on previous investigations, which utilize photogrammetry point cloud data to measure failure mode behavior of a retaining wall model, emphasizing further robust spatial testing. In this study, a comparison of two commonly used photogrammetry software packages was implemented to assess the computing performance of the method and the significance of control points in this approach. The impact of control point selection, as part of the photogrammetric modeling processes, was also evaluated. Comparisons between the two software tools reveal similar performances in capturing quantitative changes of a retaining wall structure. Results also demonstrate that increasing the number of control points above a certain number does not, necessarily, increase 3D modeling accuracies, but, in some cases, their spatial distribution can be more critical. Furthermore, errors in model reproducibility, when compared with total station measurements, were found to be spatially correlated with the arrangement of control points.

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Developing a Scene-Based Triangulated Irregular Network (TIN) Technique for Individual Tree Crown Reconstruction with LiDAR Data

Forests ◽

10.3390/f11010028 ◽

2019 ◽

Vol 11 (1) ◽

pp. 28 ◽

Cited By ~ 2

Author(s):

Haijian Liu ◽

Changshan Wu

Keyword(s):

Data Storage ◽

Shape Control ◽

Visual Analysis ◽

Control Point ◽

Average Error ◽

Control Points ◽

Tree Crown ◽

Individual Tree ◽

New Model ◽

Low Pass

LiDAR (Light Detection and Ranging)-based individual tree crown reconstruction is a challenge task due to the variable canopy morphologies and the penetrating properties of LiDAR to tree crown surfaces. Traditional methods, including LiDAR-derived rasterization, low-pass filtering smooth algorithm, and original triangular irregular network (TIN) model, have difficulties in balancing morphological accuracy and model smoothness. To address this issue, a scene-based TIN was generated with three steps based on the local scene principle. First, local Delaunay triangles were formed through connecting neighboring point sets. Second, key control points within each local Delaunay triangle, including steeple, inverted tip, ridge, saddle, and horseshoe shape control points, were extracted by analyzing multiple local scenes. These key points were derived to determine the fluctuations of forest canopies. Third, the scene-based TIN model was generated using the control points as nodes. Visual analysis indicates the new model can accurately reconstruct different canopy shapes with a relatively smooth surface, and statistical analysis of individual trees confirms that the overall error of the new model is smaller than others. Especially, the scene-based TIN derived raster reduced the average error to 0.18 m, with a standard deviation of 0.41, while the average errors of LiDAR-derived raster, low-pass filtered smooth raster, and original TIN derived raster have average errors of 0.96, 2.05, and 1.00 m, respectively. The local scene-based control point extraction also reduces data storage due to the elimination of redundant points, and furthermore the different point densities on different objects are beneficial for canopy segmentation.

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Control Points Selection Based on Maximum External Reliability for Designing Geodetic Networks

Applied Sciences ◽

10.3390/app10020687 ◽

2020 ◽

Vol 10 (2) ◽

pp. 687 ◽

Cited By ~ 2

Author(s):

Marcelo Tomio Matsuoka ◽

Vinicius Francisco Rofatto ◽

Ivandro Klein ◽

Maurício Roberto Veronez ◽

Luiz Gonzaga da Silveira ◽

...

Keyword(s):

Control Point ◽

Modern Science ◽

Geodetic Network ◽

Control Points ◽

Geodetic Networks ◽

Optimum Position ◽

Network Coordinates ◽

Detectable Bias ◽

Engineering Projects ◽

Selection Of

A set of stable and identifiable points—known as control points—are interconnected by direction, distance or height differences measurements form a geodetic network. Geodetic networks are used in various branches of modern science, such as monitoring the man-made structures, analysing the crustal deformation of the Earth, establishing and maintaining a geospatial reference frame, mapping, civil engineering projects and others. One of the most crucial components for ensuring the network quality is Geodetic Network Design. The design of a geodetic network depends on its purpose. In this paper, an automatic procedure for selection of control points is proposed. The goal is to find the optimum control points location so that the maximum influence of an anomaly measurement (outlier) on the coordinates of the network is minimum. Here, the concept of Minimal Detectable Bias defines the size of the outlier and its propagation on the network coordinates is used to describe the external reliability. The proposed procedure was applied to design a levelling network. Two scenarios were investigated: design of a network with one control point (minimally constrained levelling network) and another with two control points (over-constrained levelling network). The centre of the network was the optimum position to set the control point. Results for that network reveal that the centre of the network was the optimum position to set the control point for the minimal constraint case, whereas the over-constraint case were those with less line connections. We highlight that the procedure is a generally applicable method.

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