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2 articles matched your search query. Search Parameters:
Authors = Alex Okiemute Onojeghuo

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ALEX (307) , OKIEMUTE (2) , ONOJEGHUO (2)

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Open AccessArticle Exploiting High Resolution Multi-Seasonal Textural Measures and Spectral Information for Reedbed Mapping
Environments 2016, 3(1), 5; doi:10.3390/environments3010005
Received: 22 January 2016 / Revised: 19 February 2016 / Accepted: 22 February 2016 / Published: 25 February 2016
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Abstract
Reedbeds across the UK are amongst the most important habitats for rare and endangered birds, wildlife and organisms. However, over the past century, this valued wetland habitat has experienced a drastic reduction in quality and spatial coverage due to pressures from human related
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Reedbeds across the UK are amongst the most important habitats for rare and endangered birds, wildlife and organisms. However, over the past century, this valued wetland habitat has experienced a drastic reduction in quality and spatial coverage due to pressures from human related activities. To this end, conservation organisations across the UK have been charged with the task of conserving and expanding this threatened habitat. With this backdrop, the study aimed to develop a methodology for accurate reedbed mapping through the combined use of multi-seasonal texture measures and spectral information contained in high resolution QuickBird satellite imagery. The key objectives were to determine the most effective single-date (autumn or summer) and multi-seasonal QuickBird imagery suitable for reedbed mapping over the study area; to evaluate the effectiveness of combining multi-seasonal texture measures and spectral information for reedbed mapping using a variety of combinations; and to evaluate the most suitable classification technique for reedbed mapping from three selected classification techniques, namely maximum likelihood classifier, spectral angular mapper and artificial neural network. Using two selected grey-level co-occurrence textural measures (entropy and angular second moment), a series of experiments were conducted using varied combinations of single-date and multi-seasonal QuickBird imagery. Overall, the results indicate the multi-seasonal pansharpened multispectral bands (eight layers) combined with all eight grey level co-occurrence matrix texture measures (entropy and angular second moment computed using windows 3 × 3 and 7 × 7) produced the optimal reedbed (76.5%) and overall classification (78.1%) accuracies using the maximum likelihood classifier technique. Using the optimal 16 layer multi-seasonal pansharpened multispectral and texture combined image dataset, a total reedbed area of 9.8 hectares was successfully mapped over the three study sites. In conclusion, the study has demonstrated the value of utilizing multi-seasonal texture measures and pansharpened multispectral data for reedbed mapping. Full article
Open AccessArticle Protected Area Monitoring in the Niger Delta Using Multi-Temporal Remote Sensing
Environments 2015, 2(4), 500-520; doi:10.3390/environments2040500
Received: 12 July 2015 / Revised: 25 September 2015 / Accepted: 10 October 2015 / Published: 26 October 2015
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Abstract
Despite their importance, available information on the dynamics of forest protected areas and their management in the Niger delta are insufficient. We present results showing the distribution and structure of forest landscapes across protected areas in two states (Cross River and Delta) within
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Despite their importance, available information on the dynamics of forest protected areas and their management in the Niger delta are insufficient. We present results showing the distribution and structure of forest landscapes across protected areas in two states (Cross River and Delta) within the Niger Delta using multi-temporal remote sensing. Satellite images were classified and validated using ground data, existing maps, Google Earth, and historic aerial photographs over 1986, 2000 and 2014. The total area of forest landscape for 1986, 2000 and 2014 across the identified protected areas were 535,671 ha, 494,009 ha and 469,684 ha (Cross River) and 74,631 ha, 68,470 ha and 58,824 ha (Delta) respectively. The study showed annual deforestation rates for protected areas across both states from 1986 to 2000 were 0.8%. However, the overall annual deforestation rate between 2000 and 2014 was higher in Delta (1.9%) compared to Cross River (0.7%). This study shows accelerated levels of forest fragmentation across protected areas in both states as a side effect of the prevalence of agricultural practices and unsupervised urbanisation. The results show the need for government intervention and policy implementation, in addition to efforts by local communities and conservation organisations in protected area management across ecologically fragile areas of Nigeria. Full article
(This article belongs to the Special Issue Land Use Change in the Changing Environment)

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