National Institute of Cartography

Yaoundé, Cameroon

National Institute of Cartography

Yaoundé, Cameroon
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Abate Essi J.M.,Institute for Geological and Mining Research | Abate Essi J.M.,University of Yaounde I | Marcel J.,National Institute of Cartography | Marcel J.,University of Yaounde I | And 6 more authors.
Arabian Journal of Geosciences | Year: 2017

This work presents an interpretation of gravity data derived from the Earth Gravitational Model EGM2008 in the Center north Cameroon and a correlation with previous tectonic geological and mining studies. EGM2008 Model provides high spatial resolution gravitational data integrating land, airborne, maritime gravity data, as well as satellite altimetry data. Significant similarities are underlined through Bouguer anomaly maps deduced from EGM2008 and land gravity data according to shape, orientation, and amplitude of anomalies. Furthermore, the statistical analysis of both datasets gives means of −38.25 and −38.21 mGal as well as standard deviations of 12.30 and 12.42 for EGM2008 and land data, respectively. Regional geological formations are largely interpreted and identified on EGM2008 Bouguer anomaly map. We applied regional/residual separation filtering, upward continuation and horizontal gradient methods to investigate the subsurface structure. Some known geological lineaments are highlighted such as Poli and Koum faults and Tcholliré shear zone, while new ones are revealed. This work brings out main regional feature known as Poli-Ounianga-Kebir gravity heavy line trending SW-NE which contains uraniferous and auriferous deposits located along the same direction. This paper presents a coherent correlation between positive gravity anomalies, faults, and mineral indices in the Center-North Cameroon (Central Africa Fold belt), and thus brings new evidences of the efficiency of Earth Gravitational Model EGM2008 for structural investigation and mining exploration. © 2017, Saudi Society for Geosciences.


Fotso-Nguemo T.C.,University of Yaounde I | Fotso-Nguemo T.C.,National School of Public Works | Fotso-Nguemo T.C.,National Institute of Cartography | Vondou D.A.,University of Yaounde I | And 11 more authors.
Climate Dynamics | Year: 2017

In this paper, the regional climate model REMO is used to investigate the added value of downscaling low resolutions global climate models (GCMs) and the climate change projections over Central Africa. REMO was forced by two GCMs (EC-Earth and MPI-ESM), for the period from 1950 to 2100 under the Representative Concentration Pathway 8.5 scenario. The performance of the REMO simulations for current climate is compared first with REMO simulation driven by ERA-Interim reanalysis, then by the corresponding GCMs in order to determine whether REMO outputs are able to effectively lead to added value at local scale. We found that REMO is generally able to better represent some aspects of the rainfall inter-annual variability, the daily rainfall intensity distribution as well as the intra-seasonal variability of the Central African monsoon, though few biases are still evident. It is also found that the boundary conditions strongly influences the spatial distribution of seasonal 2-m temperature and rainfall. From the analysis of the climate change signal from the present period 1976–2005 to the future 2066–2095, we found that all models project a warming at the end of the twenty-first century although the details of the climate change differ between REMO and the driving GCMs, specifically in REMO where we observe a general decrease in rainfall. This rainfall decrease is associated with delayed onset and anticipated recession of the Central African monsoon and a shortening of the rainy season. Small-scales variability of the climate change signal for 2-m temperature are usually smaller than that of the large-scales climate change part. For rainfall however, small-scales induce change of about 70% compared to the present climate statistics. © 2017 Springer-Verlag Berlin Heidelberg


Takem B.M.,National Institute of Cartography | Takem B.M.,World Conservation Monitoring Center | Kaffo C.,National Institute of Cartography | Fish L.,World Conservation Monitoring Center
International Forestry Review | Year: 2010

The coverage of protected areas (PAs) is an indicator recommended by the Convention on Biological Diversity (CBD) to its parties for tracking progress towards the 2010 target to halt biodiversity loss. Data from the World Database on Protected Areas and other sources show that 10.6 percent (5 million hectares) of the area of Cameroon is covered by PAs. Of these, 45 percent (2.2 million hectares) of PAs coverage were designated after Cameroon signed the CBD. National parks cover 3.1 million hectares corresponding to 61 percent of the area protected with 11 of the 20 parks classified under IUCN category II. Forest and wildlife reserves comprise 940 242 and 869 428 hectares or 18 percent and 17 percent of land protected respectively. Nationally, Cameroon has invested efforts in attaining the Convention's target regarding PAs coverage and is equally involved with the creation of trans-boundary PAs.


Moyou-Somo R.,University of Yaounde I | Moyou-Somo R.,Institute of Medical Research and Medicinal Plants Studies IMPM | Essomba P.,University of Yaounde I | Songue E.,University of Yaounde I | And 7 more authors.
BMC Public Health | Year: 2013

Background: Malaria is ranked as the major public health problem in Cameroon, representing 50% of illness in less than five year old children, 40-45% of medical consultation and 40% of the annual home income spent on health. The Cameroon Oil Transportation Company (COTCO) that exploits the Chad-Cameroon pipeline in Cameroon territory, initiated in 2010, a public private partnership project to control malaria along the pipeline corridor. A research component was included in the project so as to guide and evaluate the control measures applied in this pipeline corridor. This study presents the baseline socio-anthropological data as well as the knowledge, attitudes and practices of the local population concerning malaria, its transmission, management and prevention. Methods. A descriptive cross-sectional survey was undertaken in four sentinel sites (one site per ecological zone) along the Chad-Cameroon pipeline corridor. Three structured questionnaires were used for the survey. Two of them were addressed to the heads of households (one for census and the other to collect information concerning the characteristics of houses and living conditions in households as well as their knowledge, attitudes and practices concerning malaria). The last questionnaire was used to collect information on malaria management and prevention. It was addressed to women who had delivered a living child within the past three years. Interviewers were recruited from each village and trained for two consecutive days on how to fill the different questionnaires. All data were analysed at 5% significant level using Epi-Info, SPSS and Cs PRO 4.0 STATA. Values of p ≤ 0.05 were considered statistically significant. Results: Interviews were conducted in 2597 households (Bipindi 399, Bélabo 835, in Meidougou 820 and Dompta 543). Whatever the study site, 50% of the heads of household were workers of the agro-pastoral sector. Most of the heads of household were men (average 77.4% for men and 22.6% for females). The walls of households were mostly made-up of earth blocks and access to media was low. There were significant differences between mean ages and educational level of the heads of household. Significant differences were also observed between the characteristics of houses and the sites located in the southern regions (Bipindi and Bélabo) and those located in the northern regions (Meidougou and Dompta). The later household heads were younger and less educated than those in the other regions.In most of the study sites, paracetamol was cited as the first intention drug for malaria treatment, followed by chloroquine, a banned drug. More than half of the households studied had a correct knowledge of malaria and its mode of transmission: 120/155 (77.1%) in Bipindi, 244/323 (74.5%) in Bélabo, 171/235 (72.8%) in Meidougou and 118/218 (54.1%) in Dompta. Fever and headache were the malaria signs/symptoms most often cited by the households. An important percentage of pregnant women did not take any malaria prophylaxis during their last pregnancy (up to 43.4% in Bélabo). Conclusion: In all the study sites, there were conditions that indicated the all year round transmission of malaria (characteristics of houses and limited access to media making sensitization campaigns difficult). In general, most households had a good knowledge of malaria and its mode of transmission. However, malaria treatment drugs were most often inappropriate. In this study, recommendations were made in order to guide the implementation of control measures. © 2013 Moyou-Somo et al.; licensee BioMed Central Ltd.


Ngando A.M.,Tokyo International Center | Ngando A.M.,National Institute of Cartography | Nouayou R.,University of Yaounde I | Tabod T.C.,University of Yaounde I | Manguelle-Dicoum E.,University of Yaounde I
Geofisica Internacional | Year: 2011

The Adamawa Fault is a tectonic structure related to the Cameroon Volcanic Line. Accurate AMT measurements were made on an approximately 1,600 km2 feld around the Tibati locality. This area is not well known geologically and the latest data available were compiled 50 years ago. This paper describes main stages followed for the electromagnetic determination of the fault signature. The results show several anomalous zones, attributed to the Shear Zone. They give an idea about the real electrical resistivity structure and make it possible to have a representation of the Tibati Shear Zone. These results are the preliminary of a study of Precambrian faulted structure. Important values and variations of the apparent resistivity in the study zone are provided. This feature is characterized by narrowness and great complexity.


Meli'i J.L.,University of Yaounde I | Njandjock P.N.,University of Yaounde I | Njandjock P.N.,National Institute of Cartography | Gouet D.H.,University of Yaounde I
Journal of Environmental Hydrology | Year: 2011

Magnetotelluric (MT) stations were set up to locate potential groundwater resources in the crystalline basement complex in southern Cameroon. The results have revealed the presence of two aquifers units. The first unit is the shallow or phreatic aquifer located in the sandy weathered layer. It has a mean resistivity value of 100 ohm.m and a mean thickness of 8 m. It is not present in all stations and its thickness and depth of occurrence vary within the site under the lateritic crust layer. The second unit is a deep aquifer, located in the fractured bedrock and has a mean resistivity value of 900 ohm.m and a mean thickness of 30 m. Correlation with data of existing water points (boreholes and hand-dug wells) demonstrates that, in the study area, the first unit is erratic and can be easily contaminated by human activities. So, at some sites, it is not possible to improve traditional hand-dug wells. Generally, only drilling is suitable.


Tsozue D.,University of Maroua | Nghonda J.P.,National Institute of Cartography | Mekem D.L.,University of Maroua
Solid Earth | Year: 2015

The impact of direct-seeding mulch-based cropping systems (DMC), direct seeding (DS) and tillage seeding (TS) on Sorghum yields, soil fertility and the rehabilitation of degraded soils was evaluated in northern Cameroon. Field work consisted of visual examination, soil sampling, yield and rainfall data collection. Three fertilization rates (F1: 100 kg ha-1 NPK + 25 kg ha-1 of urea in DMC, F2: 200 kg -1 NPK + 50 kg ha-1 of urea in DMC and F3: 300 kg ha-1 NPK + 100 kg ha-1 of urea in DMC) were applied to each cropping system (DS, TS and DMC), resulting in nine experimental plots. Two types of chemical fertilizer were used (NPK 22.10.15 and urea) and applied each year from 2002 to 2012. Average Sorghum yields were 1239, 863 and 960 kg ha-1 in DMC, DS and TS, respectively, at F1, 1658, 1139 and 1192 kg ha-1 in DMC, DS and TS, respectively, at F2, and 2270, 2138 and 1780 kg ha-1 in DMC, DS and TS, respectively, at F3. pH values were 5.2-5.7 under DMC, 4.9-5.3 under DS and TS and 5.6 in the control sample. High values of cation exchange capacity were recorded in the control sample, TS system and F1 of DMC. Base saturation rates, total nitrogen and organic matter contents were higher in the control sample and DMC than in the other systems. All studied soils were permanently not suitable for Sorghum due to the high percentage of nodules. F1 and F2 of the DS were currently not suitable, while F1 and F3 of DMC, F3 of DS and F1, F2 and F3 of TS were marginally suitable for Sorghum due to low pH values. © Author(s) 2015.

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