Latest Research on GIS Techniques: April 2021

A methodological approach of climatological modelling of air temperature and precipitation through GIS techniques

This study proposes an empirical methodology for modelling and mapping the air temperature (mean maximum, mean and mean minimum) and total precipitation, all of which are monthly and annual, using geographical information systems (GIS) techniques. The method can be seen as an alternative to classical interpolation techniques when spatial information is available. The geographical area used to develop and apply this model is Catalonia (32 000 km2, northeast Spain). We have developed a multiple regression analysis between these meteorological variables as the dependent ones, and some geographical variables (altitude (ALT), latitude (LAT), continentality (CON), solar radiation (RAD) and a cloudiness factor (CLO)) as the independent ones. Data for the dependent variables were obtained from meteorological stations, and data for the independent variables were elaborated from a 180 m resolution digital elevation model (DEM). Multiple regression coefficients (bn) were used to build final maps, using digital layers for each independent variable, and applying basic GIS techniques. The results are very satisfactory in the case of mean air temperature and mean minimum air temperature, with coefficients of determination (R2) between 0.79 and 0.97, depending on the month; in the case of mean maximum air temperature, R2 ranges between 0.70 and 0.89, while in the case of precipitation, it ranges between 0.60 and 0.91. [1]

GIS techniques for creating river terrain models for hydrodynamic modeling and flood inundation mapping

Two- and three-dimensional (2D/3D) hydrodynamic models require the geometric description of river bathymetry and its surrounding area as a continuous surface. These surface representations of river systems are also required in mapping flood inundation extents. Creating surface representations of river systems is a challenging task because of issues associated with interpolating river bathymetry, and then integrating this bathymetry with surrounding topography. The objectives of this paper are to highlight key issues associated with creating an integrated river terrain, and propose GIS techniques to overcome these issues. The following techniques are presented in this paper: mapping and analyzing river channel data in a channel fitted coordinate system; interpolation of river cross-sections to create a 3D mesh for main channel; and integration of interpolated 3D mesh with surrounding topography. These techniques are applied and cross-validated by using datasets from Brazos River in Texas, Kootenai River in Montana, and Strouds Creek in North Carolina. Creation of a 3D mesh for the main channel using a channel-fitted coordinate system and subsequent integration with surrounding topography produces a coherent river terrain model, which can be used for 2D/3D hydrodynamic modeling and flood inundation mapping. Although techniques presented in this paper produce better results compared to existing GIS methods, the linear approach has some limitations which can be overcome by accounting for channel meanders, sinuosity and thalweg location. [2]

An experiment in archaeological site location: Modeling in the Netherlands using GIS techniques

Regional models portraying archaeological expectation or sensitivity based on knowledge of the current archaeological situation can be of great use to archaeologists in the Netherlands. If past work can be used to guide future efforts to the most archaeologically sensitive regions, benefits in efficiency, cost‐reduction, preservation, etc. can be realized. A GIS‐based approach to archaeological modeling is described that summarizes archaeological expectation along multiple environmental dimensions. The approach is based on a mix of objective data together with archaeological experience and expertise. An application to the Regge Valley region of the Netherlands shows excellent results in terms of archaeological expectation and performance on known site samples. These results are placed within the context of the many problems and difficulties that modeling research must address in this area of Europe, and a variety of suggested improvements are offered. [3]

GIS-Based Assessment of Land Suitability for Industrial Crops (Cotton, Sesame and Groundnut) in the Abyan Delta, Yemen

We investigated the potential and capability of GIS as a technique for integrating spatial and biophysical attribute data to produce land suitability maps of the main industrial irrigated cropland (cotton, groundnut, and sesame) cultivated in the Abyan, Yemen Delta, In order to improve decision-maker strategies. We collected 64 soil samples in a systematic, georeferenced soil survey. Spatial overlay of detailed soil site characteristics, physical site qualities, and crop specific requirements was performed to reveal areas suitable for crop production. Our results of the land suitability classification for cotton, sesame and groundnut indicated that the highly suitable class (S1) accounts 22.2%, 22.6% and 22.8%, while moderately suitable (S2) constitutes 36.7%, 37.2% and 37.4% and the marginally suitable (S3) are 13.1%, 13.1% and 12.5% respectively. Whereas, currently not suitable (N1) accounts 1.9%, 1.7% and 1.3% and the permanently not suitable constitutes 26.1%, 26.1% and 26.1% respectively. However, our results also reveal the total land suitability for the mentioned crops comprise 14862 ha (27.7%) is unsuitable (N1 & N2) and 38739 ha (72.3%) represent S1, S2 and S3 of the total land area. This study provides an approach to identify and classify land in relation to the suitability to support selected industrial cropland. It also provides insights for proper land use planning and appropriate management, which could help policy makers, planners, and decision-makers align development projects with the concurrent goal of improving long-term agricultural productivity. A GIS based approach for evaluating land is useful for sustainable agricultural planning. [4]

Analysis of Accessibility to Healthcare Facilities in Giwa and Tofa Local Government Areas of Nigeria: GIS Approach

Aim: The objective of the National Health Policy (1988) in Nigeria is to provide the population with access to primary, secondary and tertiary healthcare as needed through a functional referral system. In this paper, Geographic Information System (GIS) is employed to examine a very important aspect of the policy, that is, accessibility to healthcare facilities in the rural areas which constitute a very large population of the country.
Study Design: The situation in Giwa and Tofa Local Government Areas respectively in Kaduna and Kano States of North western Nigeria is examined, with a view to identify the patronage pattern and the level of accessibility to the healthcare facilities in the rural areas in order to guide healthcare policy formulation and implementation in Nigeria.
Methodology: Locational access to healthcare facilities was established for all the 26 electoral wards across Giwa and Tofa LGAs. Using network analyst tool in ArcGIS, cost OD (Origin Destination) matrix was created using the population weighted centroid of each electoral ward as origins and the healthcare facilities as destinations. The average nearest neighbourhood analysis was done to determine the spatial randomness of the healthcare facilities. From these data, indices of community healthcare accessibility for the LGAs neighbourhoods were constructed. In addition, structured questionnaires were administered through a systematic random sampling to patients at the General hospitals in the LGAs and oral interviews conducted with those who do not patronise the hospitals. The data from the questionnaire survey was analysed using both the descriptive and inferential statistics.
Results: Findings showed that healthcare facilities in some of the wards are grossly inadequate, their distribution is random hence many of the electoral wards are poorly served or underserved. Findings revealed that some people travel a distance of up to 30km to access the nearest healthcare facility.
Conclusion: There is the need for provision of more healthcare centres in the areas which should be distributed fairly and logically. [5]

Reference

[1] Ninyerola, M., Pons, X. and Roure, J.M., 2000. A methodological approach of climatological modelling of air temperature and precipitation through GIS techniques. International Journal of Climatology: A Journal of the Royal Meteorological Society, 20(14), pp.1823-1841.

[2] Merwade, V., Cook, A. and Coonrod, J., 2008. GIS techniques for creating river terrain models for hydrodynamic modeling and flood inundation mapping. Environmental Modelling & Software, 23(10-11), pp.1300-1311.

[3] Brandt, R., Groenewoudt, B.J. and Kvamme, K.L., 1992. An experiment in archaeological site location: modeling in the Netherlands using GIS techniques. World Archaeology24(2), pp.268-282.

[4] Hezam Al-Mashreki, M., Balem Atroosh, K., Ahmed Muflahi, A., Ahmed Obaid, N. and Caoline, K. (2015) “GIS-Based Assessment of Land Suitability for Industrial Crops (Cotton, Sesame and Groundnut) in the Abyan Delta, Yemen”, Journal of Experimental Agriculture International, 8(6), pp. 384-405. doi: 10.9734/AJEA/2015/16572.

[5] Isma’il, M., Musa, I., Salisu, A., Kim, I., Oyale, A., Maiwada, A. and Yahaya, A. (2014) “Analysis of Accessibility to Healthcare Facilities in Giwa and Tofa Local Government Areas of Nigeria: GIS Approach”, Journal of Scientific Research and Reports, 3(22), pp. 2900-2915. doi: 10.9734/JSRR/2014/8183.

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