The use of GIS technology in the development of an interactive geodetic network information system with application in Kenya

Abstract

Interactive Geodetic Information System with application in Kenya is a project that was conducted within Nairobi between May and September 2007 to demonstrate how Geographical Information System (GIS) and other support software can be used to solve problems at Survey of Kenya related to data storage, retrieval, display and updating of the geodetic control network information. It examines data in the card system and introduces a database approach which IS linked to a GIS. This system is developed with ArcGIS 9.2 and Access Database. Macromedia Dreamweaver 8 and Fireworks 8 were also used for internet applications and viewing of geodetic network control monuments. Visual Basic2005 was used for developing transformation programmes. The database query function provides searches by station name, station identifier or by map sheet number. Searches by map sheet number retrieve control stations within a map sheet. It introduces a means of computing transformation of coordinates using double-precision format. A computer programme to interactively transform from geocentric Cartesian coordinates to geodetic coordinates and vice versa was developed. This programme carries a subroutine that can interactively project these coordinates according to UTM. The study on the database focuses on horizontal and vertical control data. The information used is based on data available from the recent (2003) digital mapping of Nairobi and the existing records within the Geodetic Division of Survey of Kenya. Monuments were photographed with a digital camera at close range from different positions and their images included in the database. Benchmarks were coordinated by a hand-held GPS so as to enable display in a GIS. The results generated by this new system show an improvement over the old system in the areas of data storage, retrieval speed, coordinate transformation and presentation of details. Interactive querying of the geodetic control network stations on the map is now possible.