scholarly journals Quality Assessment of TanDEM-X DEMs, SRTM and ASTER GDEM on Selected Chinese Sites

2021 ◽  
Vol 13 (7) ◽  
pp. 1304
Author(s):  
Haijiao Han ◽  
Qiming Zeng ◽  
Jian Jiao
Keyword(s):  
Land Cover ◽  
Quality Assessment ◽  
Normal Distribution ◽  
Incidence Angle ◽  
Strong Relationship ◽  
Slope Aspect ◽  
Aster Gdem ◽  
Vertical Accuracy ◽  
New Perspective

Digital elevation models (DEMs) are the basic data of science and engineering technology research. SRTM and ASTER GDEM are currently widely used global DEMs, and TanDEM-X DEM, released in 2016, has attracted users’ attention due to its unprecedented accuracy. These global datasets are often used for local applications and the quality of DEMs affects the results of applications. Many researchers have assessed and compared the quality of global DEMs on a local scale. To provide some additional insights on quality assessment of 12- and 30-m resolution TanDEM-X DEMs, 30-m resolution ASTER GDEM and 30-m resolution SRTM, this study assessed differences’ performance in relation to not only geographical features but also the ways in which DEMs have been created on selected Chinese sites, taking ICESat/GLAS points with 14-cm absolute vertical accuracy but size of 70-m diameter and 12-m resolution TanDEM-X DEM with less than 10-m absolute vertical accuracy as the reference data for comprehensive quality evaluation. When comparing the three 30-m DEMs with the reference DEM, an improved Least Z-Difference (LZD) method was applied for co-registration between models, and Quantile–Quantile (Q-Q) plot was used to identify if the DEM errors follow a normal distribution to help choose proper statistical indicators accordingly. The results show that: (1) TanDEM-X DEMs have the best overall quality, followed by SRTM. ASTER GDEM has the worst quality. The 12-m TanDEM-X DEM has significant advantages in describing terrain details. (2) The quality of DEM has a strong relationship with slope, aspect and land cover. However, the relationship between aspect and vertical quality weakens after data co-registration. The quality of DEMs gets higher with the increasing number of images used in the fusion process. The quality in where slopes opposite to the radar beam is the worst for SRTM, which could provide a new perspective for quality assessment of SRTM and other DEMs whose incidence angle files are available. (3) Systematic deviations can reduce the vertical quality of DEM. The differences have non-normal distribution even after co-registration. For researchers who want to know the quality of a DEM in order to use it in further applications, they should pay more attention to the terrain factors and land cover in their study areas and the ways in which the DEM has been created.

scholarly journals Understanding Completeness and Diversity Patterns of OSM-Based Land-Use and Land-Cover Dataset in China

2020 ◽  
Vol 9 (9) ◽  
pp. 531
Author(s):  
ShuZhu Wang ◽  
Qi Zhou ◽  
YuanJian Tian
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Quality Assessment ◽  
Socioeconomic Factors ◽  
Reference Dataset ◽  
Diversity Pattern ◽  
Diversity Patterns ◽  
Intrinsic Quality ◽  
Accuracy Measures

OpenStreetMap (OSM) data are considered essential for land-use and land-cover (LULC) mapping despite their lack of quality. Most relevant studies have employed an LULC reference dataset for quality assessment, but such a reference dataset is not freely available for most countries and regions. Thus, this study conducts an intrinsic quality assessment of the OSM-based LULC dataset (i.e., without using a reference LULC dataset) by examining the patterns of both its completeness and diversity. With China chosen as the study area, an OSM-based LULC dataset of the country was first generated and validated by using various accuracy measures. Both its completeness and diversity patterns were then mapped and analyzed in terms of each prefecture-level division of the country. The results showed the following: (1) While the overall accuracy was as high as 82.2%, most complete regions of China were not mapped well owing to a lack of diverse LULC classes. (2) In terms of socioeconomic factors and the number of contributors, higher correlations were noted for diversity patterns than completeness patterns; thus, the diversity pattern is a better reflection of socioeconomic factors and the spatial patterns of contributors. (3) Both the completeness and the diversity patterns can be combined to better understand an OSM-based LULC dataset. These results indicate that it is useful to consider diversity as a supplement for intrinsically assessing the quality of an OSM-based LULC dataset. This analytical method can also be applied to other countries and regions.

scholarly journals Evaluation of the Vertical Accuracy of Open Global DEMs over Steep Terrain Regions Using ICESat Data: A Case Study over Hunan Province, China

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4865 ◽  
Author(s):  
Zhiwei Liu ◽  
Jianjun Zhu ◽  
Haiqiang Fu ◽  
Cui Zhou ◽  
Tingying Zuo
Keyword(s):  
Land Cover ◽  
Regional Scale ◽  
Morphological Characteristics ◽  
Hunan Province ◽  
South Central ◽  
Vertical Accuracy ◽  
Dem Accuracy ◽  
Elevation Model ◽  
Terrain Elevation

The global digital elevation model (DEM) is important for various scientific applications. With the recently released TanDEM-X 90-m DEM and AW3D30 version 2.2, the open global or near-global coverage DEM datasets have been further expanded. However, the quality of these DEMs has not yet been fully characterized, especially in the application for regional scale studies. In this study, we assess the quality of five freely available global DEM datasets (SRTM-1 DEM, SRTM-3 DEM, ASTER GDEM2, AW3D30 DEM and TanDEM-X 90-m DEM) and one 30-m resampled TanDEM-X DEM (hereafter called TDX30) over the south-central Chinese province of Hunan. Then, the newly-released high precision ICESat-2 (Ice, Cloud, and land Elevation Satellite-2) altimetry points are introduced to evaluate the accuracy of these DEMs. Results show that the SRTM1 DEM offers the best quality with a Root Mean Square Error (RMSE) of 8.0 m, and ASTER GDEM2 has the worst quality with the RMSE of 10.1 m. We also compared the vertical accuracies of these DEMs with respect to different terrain morphological characteristics (e.g., elevation, slope and aspect) and land cover types. It reveals that the DEM accuracy decreases when the terrain elevation and slope value increase, whereas no relationship was found between DEM error and terrain aspect. Furthermore, the results show that the accuracy increases as the land cover type changes from vegetated to non-vegetated. Overall, the SRTM1 DEM, with high spatial resolution and high vertical accuracy, is currently the most promising dataset among these DEMs and it could, therefore, be utilized for the studies and applications requiring accurate DEMs.

scholarly journals Vertical Accuracy of Freely Available Global Digital Elevation Models (ASTER, AW3D30, MERIT, TanDEM-X, SRTM, and NASADEM)

2020 ◽  
Vol 12 (21) ◽  
pp. 3482
Author(s):  
Evelyn Uuemaa ◽  
Sander Ahi ◽  
Bruno Montibeller ◽  
Merle Muru ◽  
Alexander Kmoch
Keyword(s):  
Land Cover ◽  
Reference Model ◽  
Digital Elevation Models ◽  
Systematic Evaluation ◽  
Slope Aspect ◽  
Research Fields ◽  
Digital Elevation ◽  
Geographic Regions ◽  
Vertical Accuracy ◽  
Dem Accuracy

Freely available global digital elevation models (DEMs) are important inputs for many research fields and applications. During the last decade, several global DEMs have been released based on satellite data. ASTER and SRTM are the most widely used DEMs, but the more recently released, AW3D30, TanDEM-X and MERIT, are being increasingly used. Many researchers have studied the quality of these DEM products in recent years. However, there has been no comprehensive and systematic evaluation of their quality over areas with variable topography and land cover conditions. To provide this comparison, we examined the accuracy of six freely available global DEMs (ASTER, AW3D30, MERIT, TanDEM-X, SRTM, and NASADEM) in four geographic regions with different topographic and land use conditions. We used local high-precision elevation models (Light Detection and Ranging (LiDAR), Pleiades-1A) as reference models and all global models were resampled to reference model resolution (1m). In total, 608 million 1x1 m pixels were analyzed. To estimate the accuracy, we generated error rasters by subtracting each reference model from the corresponding global DEM and calculated descriptive statistics for this difference (e.g., median, mean, root-mean-square error (RMSE)). We also assessed the vertical accuracy as a function of the slope, slope aspect, and land cover. We found that slope had the strongest effect on DEM accuracy, with no relationship for slope aspect. The AW3D30 was the most robust and had the most stable performance in most of the tests and is therefore the best choice for an analysis of multiple geographic regions. SRTM and NASADEM also performed well where available, whereas NASADEM, as a successor of SRTM, showed only slight improvement in comparison to SRTM. MERIT and TanDEM-X also performed well despite their lower spatial resolution.

Gaining a new perspective on the quality of parent–adolescent relationships from adolescent speech samples.

2020 ◽  
Vol 34 (8) ◽  
pp. 938-948
Author(s):  
Sarah McKenna ◽  
Alison Hassall ◽  
Richard O'Kearney ◽  
Dave Pasalich
Keyword(s):  
Adolescent Relationships ◽  
New Perspective

Expert System for Quality Assessment of Electronic Book Exhibitions

2013 ◽  
pp. 32-39
Author(s):  
Svetlana V. Savkina
Keyword(s):  
Expert System ◽  
Quality Assessment ◽  
Electronic Book ◽  
Electronic Books ◽  
Comparison Of The Results

The article presents the results of testing the complex methodology of assessment of quality of electronic books exhibitions (EBE). The author describes the project of the expert system, allowing to implement the EBE assessment without the experts’ participation. There is given the comparison of the results of assessments, carried out by experts and by the expert system.

Quality of cytogenetic investigations: problems and ways for improvement

2020 ◽  
pp. 22-24
Author(s):  
В.Г. Антоненко ◽  
Н.В. Шилова ◽  
Е.Н. Лукаш ◽  
Э.Р. Бабкеева ◽  
В.Н. Малахов
Keyword(s):  
Quality Assessment ◽  
Russian Federation ◽  
Chromosomal Analysis ◽  
Common Causes

Представлены результаты экспертной оценки качества цитогенетических исследований в лабораториях РФ в системе межлабораторных сличительных испытаний «ФСВОК» в 2018-2019 гг. Обсуждаются наиболее частые причины неудовлетворительных результатов экспертизы и возможные пути улучшения качества цитогенетических исследований. We report the results of quality assessment for preparation of cytogenetic slides and chromosomal analysis in the laboratories of Russian Federation in the system of the interlaboratory comparative examinations “FSVOK” in 2018-2019. Common causes of poor results of assessment and the ways for improvement of quality for cytogenetic investigations are discussed.

ABOUT NECESSITY OF MATHEMATICAL MODELING OF THE BUSINESS PROCESS OF COST ESTIMATE CALCULATIONS IN THE CONSTRUCTION OF OIL AND GAS FACILITIES

2017 ◽  
pp. 139-145
Author(s):  
R. I. Hamidullin ◽  
L. B. Senkevich
Keyword(s):  
Mathematical Modeling ◽  
Quality Assessment ◽  
Business Process ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Construction Organizations ◽  
The Cost ◽  
Cost Of Construction

A study of the quality of the development of estimate documentation on the cost of construction at all stages of the implementation of large projects in the oil and gas industry is conducted. The main problems that arise in construction organizations are indicated. The analysis of the choice of the perfect methodology of mathematical modeling of the investigated business process for improving the activity of budget calculations, conducting quality assessment of estimates and criteria for automation of design estimates is performed.

STUDY OF INACCURACY IN THE OPERATION OF THE MAIN CONTROLLER OF STB MACHINE

2019 ◽  
Keyword(s):  
Normal Distribution ◽  
Stable Process ◽  
Random Errors ◽  
Actual Length ◽  
Experimental Data Processing ◽  
Set Up ◽  
Main Regulator ◽  
Transmission Gear ◽  
Selection Of

At production of fabrics, including fabrics for agricultural purpose, an important role is played by the cor-rect adjustment of operation of machine main regulator. The quality of setup of machine main controller is determined by the proper selection of rotation angle of warp beam weaving per one filling thread. In the pro-cess of using the regulator as a result of mistakes in adjustment, wear of transmission gear and backlashes in connections of details there are random changes in threads length. The purpose of the article is the research of property of random errors of basis giving by STB machine regulator. Mistakes can be both negative, and positive. In case of emergence only negative or only positive mistakes operation of the machine becomes im-possible as there will be a consecutive accumulation of mistakes. As a result of experimental data processing for stable process of weaving and the invariable diameter of basis threads winding of threads it is revealed that the random error of giving is set up as linear function of the accidental length having normal distribution. Measurements of accidental deviations in giving of a basis by the main regulator allowed to construct a curve of normal distribution of its actual length for one pass of weft thread. The presented curve of distribution of random errors in giving of a basis is the displaced curve of normal distribution of the accidental sizes. Also we define the density of probability of normal distribution of basis giving errors connected with a margin er-ror operation of the main regulator knowing of which allows to plan ways of their decrease that is important for improvement of quality of the produced fabrics.

Assessing Medical Evidence

2018 ◽  
Author(s):  
Jacob Stegenga
Keyword(s):  
Quality Assessment ◽  
Randomized Trials ◽  
Empirical Studies ◽  
Allocation Concealment ◽  
Assessment Tools ◽  
Medical Evidence ◽  
Empirical Methods ◽  
First Order ◽  
First Order Methods

Medical scientists employ ‘quality assessment tools’ to assess evidence from medical research, especially from randomized trials. These tools are designed to take into account methodological details of studies, including randomization, subject allocation concealment, and other features of studies deemed relevant to minimizing bias. There are dozens of such tools available. They differ widely from each other, and empirical studies show that they have low inter-rater reliability and low inter-tool reliability. This is an instance of a more general problem called here the underdetermination of evidential significance. Disagreements about the quality of evidence can be due to different—but in principle equally good—weightings of the methodological features that constitute quality assessment tools. Thus, the malleability of empirical research in medicine is deep: in addition to the malleability of first-order empirical methods, such as randomized trials, there is malleability in the tools used to evaluate first-order methods.

scholarly journals Systematic Analysis of Literature on the Marketing of Healthcare Systems. Challenges for Russian and Romanian Healthcare Systems

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 656
Author(s):  
Vladimir Bulatnikov ◽  
Cristinel Petrişor Constantin
Keyword(s):  
Quality Of Healthcare ◽  
Healthcare Systems ◽  
Business Environment ◽  
Competitive Advantages ◽  
Systematic Analysis ◽  
Scientific Databases ◽  
Advantages And Disadvantages ◽  
Funds Allocation ◽  
New Perspective

This paper aims at finding the most dominant ideas about the marketing of healthcare systems highlighted in the mainstream literature, with a focus on Russia and Romania. To reach this goal, a systematic analysis of literature was conducted and various competitive advantages and disadvantages of the medical models that require special attention from the governments are considered. In this respect we examined 106 papers published during 2006 to 2020 found on four scientific databases. They were selected using inclusion and exclusion criteria according to PRISMA methodology. The main findings of the research consist of the opportunity to use marketing tools in order to improve the quality of healthcare systems in the named countries. Thus, using market orientation, the managers of healthcare systems could stimulate the innovation, the efficiency of funds allocation and the quality of medical services. The results will lead to a better quality of population life and to an increasing of life expectancy. As this paper reviews some articles from Russian literature, it can add a new perspective to the topic. These outcomes have implications for government, business environment, and academia, which should cooperate in order to develop the healthcare system using marketing strategies.

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