Impact of datum transformation on local variations of geometric geoid in Niger

In this study, we have conducted an investigation on the impact of the coordinates’ transformation on local variations of geometric geoid. The study area is limited by 1°43′12″ to 4°00′37″ East and 13°01′57″ to 14°31′20″ North in the southwest of the Niger Republic. We used 39 network GPS/levelling points es­tablished by the Japan International Cooperation Agency (JICA) and the National Geographic Institute of Niger (IGNN), including the DOPPLER point ANG302/no.65. Using other coordinates of point no. 65 pro­vided by IGNN, we transformed the points into WGS84 and computed a new geometric geoid model. The comparison of the new model with EGM2008 geoid up to d/o 2160 gives the STD of 15 cm and the RMS of 16cm. Local variations of the geometric geoids, were compared to that of EGM2008 geoid. The comparison through basic statistics, trend lines and 3D overlaps, showed a similar trend between the geometric geoid from the transformed coordinates and that of EGM2008. On the contrary, the JICA-IGNN geometric geoid generated an opposite and exaggerated trend. The Jarque-Bera test confirms that the three samples follow a normal distribution at the significance level α = 5%. The equality of variances between EGM2008 and JICA-IGNN geoids has been rejected by the Fisher’s F-Test/two-tailed at α = 10%. However the test confirms the variances equality between EGM2008 and the transformed geometric geoid at α = 5% and α = 10%. The two-tailed Student’s T-Test at α = 5% also confirms the equality of means between EGM2008 geoid and transformed geometric geoid samples

Choice of indicators of sustainable urban mobility for Casablanca and calculation of some indicators using a geographical information system

International audienceSustainable transportation is a direct expression of sustainable development in the transport sector. The urban transport planning must consider the four pillars of sustainability: economic, social, environmental and institutional. Casablanca, like many cities in developing countries experiencing a rapid urban growth with a great difficulty to ensure the urban transport services. Therefore, there is a low part of public transportation in the urban mobility, against a big demand on the private vehicle beside a significant presence of informal transport. This complicates the planning effort maintained by the actors in the city that provide significant efforts to ensure the operational management of urban transport. This work aims to strengthen the position of sustainability in the planning process undertaken in Casablanca. Thus, we propose to analyze, compare, and choose a set of sustainable mobility indicators adapted to the context of Casablanca including offer, demand, economic, social, environmental and governance indicators. These selected indicators are also a tool for data collection and measurement on sustainable mobility in the urban area of Casablanca. We also use a Geographical Information System environment in order to integrate public transport data and offer maps in addition to population data into a Geodatabase. Spatial analysis helps us to compute a set of selected indicators especially those related to the offer and social issues. This indicators system was used, to show the unsustainability of the urban transport system of Casablanca