American Journal of Geographic Information System最新文献

{"title":"Spatio Temporal Analysis in Forest Cover Using Google Earth Engine in Ashanti Region, Ghana","authors":"Kwaku Agyekum Codjoe, Akwasi Afrifa Acheampong","doi":"10.5923/j.ajgis.20221102.02","DOIUrl":"https://doi.org/10.5923/j.ajgis.20221102.02","url":null,"abstract":"","PeriodicalId":273375,"journal":{"name":"American Journal of Geographic Information System","volume":"404 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115559931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyzing Land Use and Change Detection in Eastern Nigeria Using GIS and Remote Sensing","authors":"E. Merem, Y. Twumasi, J. Wesley, M. Alsarari, S. Fageir, M. Crisler, C. Romorno, D. Olagbegi, A. Hines, O. S. Mwakimi, E. Nwagboso, S. Leggett, D. Foster, V. Purry, J. Washington","doi":"10.5923/J.AJGIS.20190802.06","DOIUrl":"https://doi.org/10.5923/J.AJGIS.20190802.06","url":null,"abstract":"The pace and pattern of various forms of land use change and degradation continues at alarming proportion in several areas in Sub-Saharan Africa. Given the emergent risks, recurrent subsidence and erosions rank as permanent features in some areas of the continent like Nigeria. This exacerbates natural constraints on agricultural production and poor soil quality with damage to natural areas. The severity of gullies in all that, drive the destruction of vast areas in Eastern Nigeria due to intense farming and other elements. All these types of degradation cause declines in the productive capacity of land through reduced yields. For policy makers, the problem is difficult to determine precisely due to limited access to geo-spatial assessment as a decision support tool. Accordingly, there is an urgent need for regular use of such devices in assessing the severity of land degradation and change. To fill that void, this study analyzes land degradation issues in Eastern Nigeria with the latest advances in GIS and remote sensing technologies. Emphasis is on the issues, impacts, factors, efforts and remedies. In terms of methodology, the paper adopts a mix scale approach involving descriptive statistics coupled with geo-spatial technologies of GIS and remote sensing. The results from the use of these techniques point to widespread changes involving gains, declines and degradation in the region’s landscape over the years. While the size of land types devoted to agriculture, bare soil, forest and urban land surged in the study area, bushland, grassland and areas covered by water declined from 2000 to 2017. The region also experienced greater threats from the exposure to recurrent land degradation as manifested with the occurrence of erosion hazards across various sites. The emergent spatial patterns not only revealed concentration of agricultural land class along the upland northern axis of the region along Ebonyi and Enugu and clusters of forest cover on the lower south part (Imo and Abia). GIS mappings showed the dispersion of erosion hazards in some of the states. With change attributed to a host of factors raging from competing land use made up of mining, agriculture, ineffective policy, poor conservation and environmental and physical elements. The paper suggested the need for education, effective policy, local participation, soil conservation and the design of regional land use information system as remedies.","PeriodicalId":273375,"journal":{"name":"American Journal of Geographic Information System","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114834338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multitemporal Sentinel-1SAR Interferometry for Surface Deformation Monitoring near High Dam in Aswan, Egypt","authors":"Yehia H. Miky","doi":"10.5923/j.ajgis.20190802.05","DOIUrl":"https://doi.org/10.5923/j.ajgis.20190802.05","url":null,"abstract":"The area in the downstream of Aswan High Dam is subjected to many factors that may cause a deformation on the earth surface. The existence of Lake Naser, the hesitated water table and its bad effect and the tectonic activities increase the possibility of surface elevation changes. In this study, Multitemporal Synthetic Aperture Radar (SAR) images and Differential SAR Interferometry (DinSAR) technique were used to derive terrain deformation measurements over the area near Aswan high dam. The data were processed using SNAP, Sentinel Application Platform and a two-pass interferometry technique with the help of the Shuttle Radar Topography Mission (SRTM) is performed. Based on the results, all interferograms performed have high coherence while the pixels represent water surface had a low coherence value. The surface elevation changes range between -6.5 cm and +2.4 cm in 2017, while in 2018 it ranges between -5.2 cm and +6.6 cm. it is recommended to use a longer observation time period with three-pass interferogram technique to give the independence of the external low-resolution DEM and map the annual rates of movement.","PeriodicalId":273375,"journal":{"name":"American Journal of Geographic Information System","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131611519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}