This study aimed at characterizing the urban Land Use/Cover (LU/C) types and their spatio-temporal changes in Awka Metropolis, Anambra State from a sub-pixel perspective. The study made use of Landsat satellite imageries for three epochs (1986, 2001 and 2016) covering a total of 30 years. The Ridd Model of Vegetation (V), Impervious surfaces (I), Soil (S) and Water (W) was employed by applying the Linear Spectral Mixture Analysis (LSMA) to characterize satellite image fractions for each epoch. Cellular Automata Markov (Ca-Markov) chain and the Land Change Modeller (LCM) were used to predict future LU/C for the year 2031 and the transition of each LU/C categories between 2016 and 2031, respectively. ArcGIS 10.5 and Idrisi Selva software were used for the analyses. The findings of this study indicated that vegetation reduced over the years from 181.79 sq.km in 1986 to 110.89 sq.km in 2016 while impervious surface on the other hand increased from 16.79 sq.km in 1986 to 73.34 sq.km in 2016. Areas classified as soil experienced an increase from 26.15 sq.km to 36.519 sq.km within the same period while (exposed) water fractions increased from 0.961 sq.km in 1986 to 2.748 sq.km in 2016. The prediction analysis performed revealed that by the year 2031, Awka Metropolis will be reduced to about 88.20 sq.km of vegetation; impervious surfaces is expected to increase by an additional 17.780 sq.km in 2031; soil cover also predicted to increase to 42.75 sq.km in 2031. The transition map produced in this study (between 2016 and 2031) did not only locate areas expected to transform from each LU/C category to another or areas where they may persist but also indicated that the transition of vegetation to impervious surface was most pronounced than any other category of LU/C. LU/C changes of this nature have been held as a principal cause of Urban Heat Islands (UHIs), high urban surface temperature and a major proponent of climate change. The study therefore recommends the use of sub-pixel approach in characterizing LU/C fractions especially when the level of objectivity is highly needed and/or in the modelling of non-linear and chaotic environmental phenomena, e.g. Land Surface Temperature (LST), soil moisture, erosion and flood vulnerability, etc.
Geological studies, remote sensing and geophysical investigation around twenty two boreholes (highly and moderately productive, or dry ones) have clarified aquifers productivity factors of the crystalline basement of Burkina Faso as well as their geophysical signature. To boost the rate of successful siting of highly productive boreholes (rate greater than 5 m3 / h) from 15 to 56%, the square device enabling to perform anisotropy profile was tested. This system provided some very interesting results for research of high yielding drilling sites.
Thanks to electrical and electromagnetic geophysical methods after a geological and remote sensing study, ten sites with twenty-two yielding, mildly yielding or dry boreholes have been studied in details. Some number of productivity factors of crystalline rocks aquifers in Burkina Faso has been detected as the contribution of electromagnetic hydro geophysical prospecting. Migmatic granites characterize the geology of the sites. These rocks are very fractured with important pegmatic veins intrusions.
The yielding wets drilling are located on fractures longer than five kilometres.
Lateral extension of the discontinuity is less than fifty meters.
An important thickness of fractured rock is necessary, it characterize the "trailing rise" of electrical sounding curve.
There is a correlation between the yield of a borehole and the anisotropy ratio. A perpendicular anisotropic profile allows choosing a site for yielding boreholes.
A polling unit is defined as a designated location where registered voters cast their votes on election days. Information about where polling units are located and other attribute information is critical for proper planning, delivery and distribution of election materials, as well as allowing citizens to participate on an election day. The aim of this study is to map out the polling units in Ohaisu ‘A’ registration area of Afikpo using Geographic Information System (GIS). It uses analogue Topographic map (as a base map) of 1:50000 covering the project site, questionnaires to gather attribute information about each polling units and handheld (Garmin GPSMAP 76c) GPS receiver for point positioning to produce the a map of the polling units and linked with their associated attribute data using ArcGIS 10.0 software. The study reveals that information on the spatial distribution of polling unit is a yardstick to an effective and successful election exercise. Hence, this work is recommended to serve as information medium for government, electoral officers and the electorates. This is to add value to decision-making and planning processes in Nigeria election process.
Coastal zones monitoring is an important task in sustainable development and environmental protection. For coastal zones monitoring, shoreline extraction is a fundamental work. The shoreline is defined as a line of contact between land and water body. The main purposes of this study were to compare and evaluate six of shoreline extraction methods based on remotely sensed data. Those methods were digitizing, Thresholding band ratio, and classification, Normalized difference water index (NDWI), Normalized Difference Vegetation Index (NDVI), and Improved method. Those methods were applied on landsat8 2015 image to extract the shorelines position for Ras El-Hekma coastal zone. The extracted shorelines were compared with reference 2015 shoreline which detected by high resolution image Pleiades B1 (0.50 m) special resolution. A comparative study has been done depending on four evaluation criteria. The results show that all shorelines which are extracted by six methods are accepted which 90% of shifting distances with in one pixel (30 m), but The shoreline extracted by Thresholding band ratio method is the most one closed to the true shoreline where the mean value is 11.04 m, RMSE is 9.54 m about one third the value of the pixel size (30 m) of landsat 8 image, and 94.44% of the shoreline segments lie within 1 pixel distance of the true shoreline. The fourth evaluation criteria D90% is 22.35 m, which 90% of shifting distances between extracted and true shoreline is ling in.
The surface water of river basins in particular the Sahel region of north – east Nigeria show very sensitive inter-annual fluctuations due to climate changes. Seasonal changes of climatic indices on water level of six rivers: Dadin-kowa, Jimeta, Donga, Geidam, Alau and Jamaare of north-east Nigeria were examined by modeling the changes of mean monthly rainfall, temperature, relative humidity and evaporation. Trends in seasonal climatic indices were analyzed using Mann-Kendall test to determine their effect on gauge water level of rivers in north-east Nigeria. The result indicated significant effects of climate indices on gauge water level with decadal mean temperature and evaporation ranging between 24.1 – 31.4°C and 3 – 7.5 mm respectively across the region. Similarly, the positive impacts of climatic indices from rainfall and relative humidity ranged between 8 – 2127 mm and 28.6 – 71.4% respectively. Pathway effects among climatic variables quantitatively revealed that the highest impact on water level was evaporation (89.8%) then temperature (82.1%) relative humidity (78.3%) and rainfall (71.2%), respectively. Although the effects of climatic indices varied within different locations, they generally impacted significantly on the water levels within the sub-region.