Establishment and maintenance of a new geospatial frame for Tanzania-TZRF10
Abstract
Tanzania like most of the African countries has an old and conventional Geodetic Network. This network was established and computed by the Directorate of Overseas Surveys (DOS) of Great Britain in the 1950’s. The present network is based on the 30th arc-meridian of the Clarke 1880 modified ellipsoid with its origin at Buffelsfontein-Cape Town in the Republic of South Africa. The present network does not satisfy the overgrowing mapping requirements of the country as well as other Geo-related information requirements. They include homogeneous cross border mapping activities (most of the international boundaries have not been physically defined), smooth land regularization projects in new urban areas, production and update of large scale topographical maps in urban areas and homogenous spatial mapping as well as the studies of crustal dynamics as related to plate tectonics and natural hazards associated with seismic or volcanic activities.
The Survey and Mapping Division of Tanzania (SMD) has realized the values of high precision and geocentric dynamic spatial frame in facilitating the geodetic positioning (coordinates and velocities in the geocentric coordinate system), navigation and general purpose spatial referencing to date as the most versatile, accurate and economical way of addressing the above issues. In view of those values and strong capabilities of modern dynamic geodetic frames, Tanzania has been collaborating with other African countries to establish a unified African Geodetic Reference Frame (AFREF). However, lack of appropriate expertise, proper awareness of the concept amongst most of the national mapping organizations and differences in economic levels in the African countries have always been the limiting factors.
In view those limitations, the primary objective of this thesis is to provide the basis for the establishment and maintenance of a 3-dimensional dynamic reference frame for Tanzania in the ITRF system with optimum accuracy requirement in an economic way. The new frame will be compatible to satellite position techniques and would consider the advancement in the communication technology and the increased capacity of the internet applications real time geodetic applications that has been illustrated by Weber [2002] and Weber et al. [2003].
To achieve the research objectives a conceptual plan to realize a new spatial framework in Tanzania (TZRF10) has been developed, using the least-squares covariance analysis technique as a tool to evaluate for its geometrical consistency. A case study on reference frame maintenance using the BerneseV5.0 scientific software; has been developed and evaluated for its performance based on NAD83 (CSRS) data from the Geodetic Survey Division of Natural Resources of Canada NRCan.
The present advancement in communication technologies and increased capacity of internet–based real time geodetic applications has been illustrated through implementation of a case study and evaluated for its performance using a developed matlab software code.