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1

Enhancement of inverse-distance-weighting 2D interpolation using accelerated decline

Ruffhead Andrew Carey

Reports on Geodesy and Geoinformatics

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2023

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Vol. 116

9--14

EN

Two-dimensional interpolation - or surface fitting - is an approximation tool with applications in geodetic datum transformations, terrain modelling and geoid determination. It can also be applied to many other forms of geographic point data, including rainfall, chemical concentrations and noise levels. The problem of fitting of a smooth continuous interpolant to a bivariate function is particularly difficult if the dataset of control points is scattered irregularly. A typical approach is a weighted sum of data values where the sum of the weights is always unity. Weighting by inverse distance to a power is one approach, although a power greater than 1 is needed to ensure smooth results. One advantage over other methods is that data values can be incorporated into the interpolated surface. One disadvantage is the influence of distant points. A simple cut-off limit on distance would affect continuity. This study proposes a transition range of accelerated decline by means of an adjoining polynomial. This preserves smoothness and continuity in the interpolating surface. Case studies indicate accuracy advantages over standard versions of inverse-distance weighting.

2

Implementation of the Quality and Creating GIS Maps for Groundwater in Babylon, Iraq

Al Mousawi Eman, Jahad Udai A., Mahmoud Ammar Shaker, Chabuk Ali, Naje Ahmed Samir, Al-Ansari Nadhir, Laue Jan

Journal of Ecological Engineering

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2023

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Vol. 24, nr 8

310--321

EN

In times of water scarcity, groundwater is a vital resource that provides an alternate source of water for human consumption. In Iraq, the quality of rivers has been greatly affected by climate change and the dwindling availability of surface water. Examining and classifying the groundwater in this region is now vital. The present study sought to incorporate the groundwater property data (drinking purpose) with a geographic information system (GIS). Eleven variables were measured in 25 wells to investigate the physio-chemical properties around the Babylon province of Iraq. On the basis of the acceptability of groundwater for drinking, GWQI was categorized into four primary groups in the results. Approximately 28% of the twenty-five wells (1811.04 km2) are of excellent quality, 24% are of good quality (1552.3 km2), 44% are of low quality (2845.9 km2), and 4% are extremely contaminated (2587.2 km2). The average GWQI for the entire study region was 110.7, making it inappropriate for human consumption. It has been determined that approximately 52% of the groundwater from the examined wells can be deemed safe for consumption, although certain measurements surpass the permissible limits. To guarantee that the residents in these areas are supplied with water of superior quality and safety, treatment of the tested groundwater is recommended before use.

3

Characterization of the Chemical Properties of Deposited Red Clay Soil Using GIS Based Inverse Distance Weighted Method in Kirkuk City, Iraq

Salahalden Veyan Farhad, Shareef Muntadher Aidi, Al Nuaimy Qahtan A. M.

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 7

46--60

EN

This study focuses on the physical and chemical properties of soils and their geographical distribution, with a specific focus on red clay. The inverse distance weighting (IDW) technique, integrated with Geographic Information Systems (GIS), was employed to predict the chemical characteristics of the soil. Sampling was conducted at twenty-one locations in three areas: Bor Mountain, Jambor, and Kirkuk Hills, all located within Kirkuk City. Seven soil properties were examined: acidity, organic matter content, total dissolved salts (TDS), gypsum, chlorides, and sulfates. The chemical analysis revealed that the soil pH ranged within an acidic range. One sample exhibited a high TDS level. Chloride levels varied within a specific range. The concentration of organic matter in the soil exhibited variability. Sulfur trioxide and gypsum concentrations were found to be below average in the study region. The IDW technique effectively mapped the distribution of the different soil parameters within Kirkuk City, demonstrating a range from good to excellent accuracy. Additionally, a cross-validation method was employed to assess the correlation between the fundamental and investigated chemical properties. The results showed good to excellent degrees of correlation in the different structures studied.

4

Assessment of Groundwater Quality in the Berrechid Aquifer, Central Morocco, Using Multivariate Statistics and Water Quality Indices

Moukhliss Mohammed, Taleb Abdslam, Ouallali Abdessalam, Spalevic Velibor, Mazigh Nouhaila, El Fathi Badr, Souabi Salah

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 4

187--199

EN

Groundwater salinity is a serious problem for water quality in the irrigated parts of arid and semi-arid regions, especially in the aquifers of Berrechid, Morocco. This study used a variety of techniques, including the Water Quality Index (WQI) and World Health Organization (WHO) recommended limits, Principal Component Analysis (PCA), and Geographic Information System (GIS) to evaluate the quality of the groundwater for irrigation and domestic use in the Berrechid region in central Morocco. The goal of this study was to evaluate the quality of groundwater for irrigation and human consumption. The collection and analysis of twenty-two samples for ions was carried out, including, EC, Cl-, NO3-, NH4+, NO2-, Ca2+, Mg2+, pH, SO42-, Na+, K+, CO3-, HCO3-, and Mn2+. The Water Quality Index (WQI) was used to classify the water quality vis: excellent, good, average, poor and very poor. The research area’s water quality index (WQI) ranges from 43.89 to 439.34, with around 40.90% of samples having excellent water quality, 45.45% having poor water quality, 4.54% showing extremely bad water quality, and 9.09% having unsuitable quality for human consumption. The principal component analysis reveals that the average concentration of cations in groundwater was Na+> Mg2+> Ca2+> K+> Mn2+> NH4+, whereas the concentration of anions was Cl-> HCO3-> SO42-> NO3-> NO2-> CO32-. The correlation matrix was created and analyzed to determine its significance in groundwater quality assessment. The primary sources of pollution are household waste, exposed septic tanks, landfill leachate, and excessive fertilizer usage in agriculture and industrial operations. The current analysis demonstrates that the deteriorating groundwater quality in the region needs pre-consumption treatment and contamination risk prevention.

5

Evaluation of Soil Pollution Levels in Al-Qadisiyah Governorate, Iraq Using Contamination Index and GIS

Al-Khuzaie Marwah M., Abdul Maulud Khairul Nizam

Journal of Ecological Engineering

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2022

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Vol. 23, nr 3

206--213

EN

The precise determination of trace element concentrations in the soil of the Al-Qadisiyah Governorate is part of the Iraqi sedimentary plain is required to eliminate high levels of harmful elements in polluted soils. The soil samples were collected from 28 representative profiles in Al-Shamiyah city. The soil profiles were defined using virtual characterization. In this study, I-geo was used to analyze soil pollution. The goals and destinations of the I-geo readings Contamination of Cd, Ni, Pb, and Zn in various soil strata. I-geo (Cd) generally range from 0.58 to 4.71, I-geo (Ni) range from 0.09 to 4.07, I-geo (Pb) ranged range from 0.07 to 2.79, and I-geo (Zn) ranges from zero to 2.79, depicting the local differences in I-geo for pollutants in the research area. Suggesting that the research area had been heavily polluted from Cd in the varied layers of the soils. On the maps pertaining to Zn and Pb, the majority of the research area was primarily covered in the orange and blue hues, suggesting that a significant portion of the research area was likely to be severely polluted from Cd and Ni. Moreover, the land cover layouts of Ni in layers of the soils revealed concentrations rising towards to the western sections, which could be attributed to proximity to a major drain. The results display that its I-geo value of four trace metals generally range from non-pollute to significantly heavily polluted. The I-geo data show significant differences in levels of the Ni, Cd, Zn, and Pb in different soils strata. Including these findings, the soil in Al-Shamiya, Al-Qadisiyah Governorate contains high levels of Cd, Ni, Pb, and Zn. Industries of fossil fuel combustion, as well as other man-made wastes include agricultural nutrients, soil conditioners, and sludge, particularly, ammonium phosphate pollution in soils. The pollutant load index (PLI) reveals a baseline level of contamination in 28 locations, as well as a decline in soil quality in four others. Finally, assessing the danger of contamination for trace metals utilizing the I-geo and PLI by using the GIS method and multimodal models is a helpful and relevant strategy.

6

Neural networks for the generation of sea bed models using airborne lidar bathymetry data

Kogut T., Niemeyer J., Bujakiewicz A.

Geodesy and Cartography

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2016

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Vol. 65, no. 1

41--53

EN

Various sectors of the economy such as transport and renewable energy have shown great interest in sea bed models. The required measurements are usually carried out by ship-based echo sounding, but this method is quite expensive. A relatively new alternative is data obtained by airborne lidar bathymetry. This study investigates the accuracy of these data, which was obtained in the context of the project ‘Investigation on the use of airborne laser bathymetry in hydrographic surveying’. A comparison to multi-beam echo sounding data shows only small differences in the depths values of the data sets. The IHO requirements of the total horizontal and vertical uncertainty for laser data are met. The second goal of this paper is to compare three spatial interpolation methods, namely Inverse Distance Weighting (IDW), Delaunay Triangulation (TIN), and supervised Artificial Neural Networks (ANN), for the generation of sea bed models. The focus of our investigation is on the amount of required sampling points. This is analyzed by manually reducing the data sets. We found that the three techniques have a similar performance almost independently of the amount of sampling data in our test area. However, ANN are more stable when using a very small subset of points.

7

Interpolation-based reconstruction methods for tomographic imaging in 3D positron emission tomography

Li Y., Kummert A., Boschen F., Herzog H.

International Journal of Applied Mathematics and Computer Science

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2008

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Vol. 18, no 1

63-73

EN

Positron Emission Tomography (PET) is considered a key diagnostic tool in neuroscience, by means of which valuable insight into the metabolism function in vivo may be gained. Due to the underlying physical nature of PET, 3D imaging techniques in terms of a 3D measuring mode are intrinsically demanded to assure satisfying resolutions of the reconstructed images. However, incorporating additional cross-plane measurements, which are specific for the 3D measuring mode, usually imposes an excessive amount of projection data and significantly complicates the reconstruction procedure. For this reason, interpolation-based reconstruction methods deserve a thorough investigation, whose crucial parts are the interpolating processes in the 3D frequency domain. The benefit of such approaches is apparently short reconstruction duration, which can, however, only be achieved at the expense of accepting the inaccuracies associated with the interpolating process. In the present paper, two distinct approaches to the realization of the interpolating procedure are proposed and analyzed. The first one refers to a direct approach based on linear averaging (inverse distance weighting), and the second one refers to an indirect approach based on two-dimensional convolution (gridding method). In particular, attention is paid to two aspects of the gridding method. The first aspect is the choice of the two-dimensional convolution function applied, and the second one is the correct discretization of the underlying continuous convolution. In this respect, the geometrical structure named the Voronoi diagram and its computational construction are considered. At the end, results of performed simulation studies are presented and discussed.