Surveying and Geoinformatics - Scholarly Publications

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Browsing Surveying and Geoinformatics - Scholarly Publications by Author "Agbor, C. F."

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  • Item
    Open Access
    Geoinformatic assessment of urban heat island and land use/cover processes: a case study from Akure
    (Springer Environmental Earth Sciences, 2019) Makinde, E. O.; Agbor, C. F.
    Akure is one of the cities undergoing rapid growth in Nigeria, which has resulted to remarkable Urban Heat Island (UHI) effect. To examine the impact of this development in the city and its environs, this study derived the brightness temperatures and land use land cover (LULC) types using Landsat images between 1984 and 2016, of 190/55 path and row. Normalized Difference Built up Index (NDBI) and Normalized Difference Vegetation Index (NDVI), were used as LULC indicators for sub-pixel analysis. The results of this study revealed a remarkable change in built-up area at the expense of vegetation (forest) and bare lands. The sub-pixels analysis between land use/cover indicators and temperature revealed a strong correlation between LULC and temperature in the area. Findings revealed a 4.63 °C temperature increase in vegetated areas between 1984 and 2016; and an overall temperature values ranged from about 14 to 36 °C, which have been categorized into six classes (< 20 °C, 20 °C to < 24 °C, 24 °C to < 28 °C, 28 °C to < 32 °C, and ≥ 32 °C). The temperature increase over the years and the strong correlation between temperature and land use land cover suggests, that any small undesirable change in land use land cover in the future would lead to severe environmental condition.
  • Item
    Open Access
    Land Surface Temperature Mapping using Geoinformation Techniques
    (Geoinformatics FCE CTU, 2018) Agbor, C. F.; Makinde, E. O.
    General environmental management, which involves monitoring and modeling, requires the information of the Land surface temperature (LST) status of area concerned. Land surface temperature has gained relevance recognition over the years and there is need to develop approaches that can determine LST using satellite images. This study was conducted in Akure which has experienced rapid urbanization in recent time. The study utilized Landsat data of 1984, 1990, 2000, 2003, 2014 and 2016. The temperature data were derived from Landsat images using remote sensing algorithms for assessing LST from thermal infrared (TIR) data (bands 6 and 10). These data were processed and analyzed using tools in Idrisi and ArcGIS software systems. Satellite-derived land surface temperatures were validated with in-situ temperature data. The results revealed parabolic increase in temperature over the years and the changing pattern was investigated by adopting existing ecological indexes. The validation operation revealed average bias value of between remote sensing- and ground-based data. This implies that remote sensing technique is reliable and therefore could be employed for large scale temperature mapping. The results could be used in mitigating urban heat island effects such as heat-related stress and ill-timed human deaths.