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Multi-temporal scale of urban rainfall in the Eastern Northeast based on observed data and gridded products: physiographic factors and changes in land use and occupation
(2026-02-01)
da Silva, Luis Felipe Francisco Ferreira
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de Oliveira Romão, William Max
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Lyra, Gustavo Bastos
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da Silva, Elania Barros
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da Silva Costa, Micejane
Rainfall is one of the most important meteorological variables in the daily lives of urban populations. The city of Maceió, the capital of Alagoas, located in the eastern part of the Northeast of Brazil (ENEB), has 50 neighborhoods and a population of approximately one million people, with few studies on the subject. The objectives were: (i) to validate the CHIRPS product; (ii) to identify the preferential rainfall periods in Maceió via GIS; (iii) to map areas for the installation of in situ stations in the city with the aim of supporting the prevention of hydrometeorological disasters; and (iv) creation of a theoretical-conceptual rainfall model. The statistical indicators (R², ρ, BIAS, MAPE and RMSE) were used to validate the gridded precipitation product CHIRPS from 11 CEMADEN rain gauge stations. Monthly rain occurrence maps via Spline tension were developed by QGIS (Quantum GIS) software. The HAND model was applied at neighborhood level for the assessment of urban floods. Waterborne disease data were obtained from SINAN, Natural Disaster data via S2iD from the period 2000 to 2023, and the NDVI and EVI indices in the years 2015 and 2022 were evaluated in the study. All stations were monotonically positive (ρ > 0.65) and significant (p-value < 0.001), indicating that CHIRPS is able to capture rainfall variability despite the influences of the coast, Lagoa Mundaú, and topography. Most stations showed underestimation (negative BIAS) and lower errors (MAE and RMSE). Spatially, the increase in rainfall on the coastal plateau is due to the interaction of the wind regime with the relief, driven by the circulation of breezes and the influence of trade winds. The preferential rainfall period occurs between 04:00 am and 07:00 am. The HAND model identified very high and high susceptibility, mainly on the coast, in areas adjacent to Lagoa Mundaú, and in neighborhoods crossed by rivers and urban canals, and low susceptibility in densely populated neighborhoods. Waterborne diseases together with transformations via NDVI and EVI indicated that rainfall amplifies risk scenarios for the most vulnerable and densely populated populations. In light of this, it is perceived that the rainfall patterns in Maceió are due to the interaction of physiographic and/or anthropogenic factors and meteorological systems – theoretical-conceptual model – which requires improvements in infrastructure and an active monitoring system.
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Sustainable groundwater management through water quality index and geochemical insights in Valsad India
(2025-12-01)
Jodhani, Keval H.
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Gupta, Nitesh
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Dadia, Sanidhya
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Patel, Harsh
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Patel, Dhruvesh
Groundwater quality assessment is crucial for sustainable water resource management and public health protection. This study evaluated the Water Quality Index (WQI) of groundwater in the southern part of Gujarat focusing on the Valsad District. Groundwater in this region occurs in porous, unconsolidated formations and fracture formations, both under groundwater table conditions and confined aquifers. Various parameters including Nitrate (NO<inf>3</inf>¯), pH, Calcium (Ca2+), Electrical Conductivity (EC), Total Hardness (TH), Magnesium (Mg2+), Total Dissolved Solids (TDS), Potassium (K+), Sodium (Na+), Sulphate (SO<inf>4</inf>2−), Chloride (Cl¯), Bicarbonate (HCO<inf>3</inf>¯), Silicate (SiO<inf>4</inf>4−), and Fluoride (F¯) were analyzed to assess groundwater quality. Results indicate that most of the parameters fell within acceptable permissible limits for drinking water, except for Muli and Nanaponda villages with the parameters Cl¯, EC, and TDS exceeding the permissible limit. The WQI analysis revealed that 31.25% of water samples from different villages were found in the excellent category (WQI < 25). About 68.75% of samples from 16 villages were classified as good quality category (WQI ∼ 25–50). Overall, the WQI ranged from 14.20 to 41.98, suggesting that groundwater in the Valsad district is suitable for drinking. The Piper diagram analysis of water samples collected from the field indicated unique geochemical compositions and good water. The diagram revealed that the Ca2+ was the predominant cation, followed by K+, Na+, and Mg2+. Among the anions, the HCO<inf>3</inf>− showed the highest concentrations, followed by SO<inf>4</inf>2−, NO<inf>3</inf>−, and Cl−. This dominance pattern demonstrated that the weathering of minerals significantly influenced the groundwater. This study recommends remediation for areas with reduced water quality to address geogenic and anthropogenic contamination.
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GIS and Street View Integration: Analyzing Spatial Factors of Motorcycle Taxi Stands in Bangkok
(2024-01-01)
Rattanapitak, Wirat
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Sirikitsathian, Phatthanan
Motorcycle taxis play a vital role in addressing lastmile connectivity challenges in Bangkok's complex urban transportation system. However, the factors influencing the spatial distribution of these informal transport services remain poorly understood. Kernel Density Estimation (KDE) was employed to examine the spatial distribution patterns, revealing two primary high-density clusters of stands in southern Chatuchak. Proximity analysis quantified relationships between the 208 stand locations and urban infrastructure factors, finding strategic positioning near mass transit stations (avg. 1.79 km), on sidewalks (70.5%), and in mixed-use areas with predominantly residential (33.19%) and commercial (29.32%) land use within a 100m radius. A decision tree model identified residential area proportion (importance 0.3423) and distance from metro stations (0.2935) as key predictors of stand presence, but achieved moderate accuracy (52.38%). The results highlight the close integration of motorcycle taxi stands within the urban fabric and their role in enhancing accessibility.
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Assessment of the suitability of land use for agriculture by analytical hierarchy process: Ahp in lower prachinburi watershed, Eastern Thailand
(2020-09-01)
Rukanee, Duangthip
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Sangchan, Songvoot
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Choomjaihan, Prasan
The low Prachinburi watershed is a gateway to other regions of the country. Due to a rapid increase in population there, there is also an increase in agricultural production area. This study aims to assess the appropriateness of land use by using an analytical hierarchy process (AHP) for land use planning. The results of the study revealed that there is a moderate level of the appropriateness in land use development. The most appropriate area (S1) accounts for 22.07%; the moderately appropriate area (S2) accounts for 54.15%; the lowly appropriate area (S3) accounts for 10.25%; and the inappropriate area accounts 13.52% of the area. Regarding a guideline for agricultural area management, it is found to be most appropriate, particularly on field crop growing such as cassava, sugar cane, and maize growing and followed by rice growing and or charding (58.51%, 25.17%, and 6.04%, respectively). Only 10.25% of the total area is inappropriate for farming.
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Web-based Elderly Monitoring System with GIS
(2019-07-01)
Sriwichian, Anirut
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Boonjing, Veera
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Nillaor, Pichetwut
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Muangprathub, Jirapond
Many countries have become elderly society due to the increase ratio in the elderly population. This increase causes an impact on the elderly and society in many ways. If we are to solve problems for the elderly, it is important to have elderly information that helps understand their being and quality of life. This research aims to develop the web-based elderly monitoring system with GIS that is used to store data and assess the level of quality of life of the elderly. Afterward, the proposed system provided in a spatial data format using GIS technology. We use this system to collect all the elderly in four villages (Moo 5, 6, 7, and 8). From the using of the system in 4 villages, there were 240 elderly people who participated in providing information. The result is the quality of life information and general information, both overview and personal, which the agencies related to elderly care can be used to promote the development of the quality of life for the elderly.
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A Survey of Spatio-Temporal Database Research
(2018-01-01)
Pant, Neelabh
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Fouladgar, Mohammadhani
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Elmasri, Ramez
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Jitkajornwanich, Kulsawasd
The main purpose of spatio-temporal database systems is combining the spatial and temporal features of data. Almost all spatio-temporal applications—such as mobile communication systems, traffic control systems, and GIS with moving objects—have a common basis, which is the requirement to handle both space and time characteristics of the data. Similar to other data types, spatio-temporal data are required to be accurately modeled, structured, and queried efficiently. In this paper, we survey data models, related operations, data structures and access methods for spatial, temporal, and spatio-temporal data types. These access methods basically are enhanced variations of the well-known R-tree.
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Proving completeness of open GIS SQL spatial relationships and operations
(2017-10-19)
Jitkajornwanich, Kulsawasd
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Elmasri, Ramez
OpenGIS SQL is a standard for incorporating GIS and spatial concepts into SQL. Two types of methods are part of OpenGIS SQL: (1) boolean methods for topological relationships among spatial objects, and (2) methods for specifying spatial operations. We prove that the complete set of 2-dimensional spatial relationships defined by Egenhofer can all be specified using OpenGIS SQL operations and relationships. Our proof shows how each spatial relationship can be specified using OpenGIS SQL and thus provides users with the means of determining how each spatial relationship can be written in SQL. This provides users with enhanced usability and flexibility by providing the specific OpenGIS conditions for every possible 2- dimensional spatial relationship.
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Management of the urban spatial setting to determine the effect of urban heat island on the Bangkok Metropolis, Thailand
(2009-01-01)
Chavanavesskul, S.
Urbanization and human activities cause higher air temperatures in urban areas than the urban climate. This study uses remote sensing data to observe this urbanization and its surrounding areas. The high temperature can cause problems to the environment, such as high energy consumption on cooling, raised air pollution levels and changes in land use and the creation of a heat island in Bangkok Metropolis, Thailand. This study found that the urban heat island (UHI) problem is caused by the large size of the urban area and sparse vegetation and water resources. Some strategies and approaches are raised in this paper in order to reduce the problem. © 2009 WIT Press.

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