GIS & GPS

Global Positioning System

The Global Positioning System (GPS) is a global navigation satellite system (GNSS) developed by the United States Department of Defence and managed by the United States Air Force 50th Space Wing. It is the only fully functional GNSS in the world that can be used freely by anyone, anywhere, and is often used by civilians for navigation purposes. GPS hasbecome awidely used aid to navigation worldwide, and a useful tool for map-making, landsurveying, commerce, scientific uses, tracking and surveillance.

           

This is how GPS works:

• It uses a constellation of between 24 and 32 medium Earth orbit satellites thattransmit precise radio wave signals, which allow GPS receivers to determine theircurrent location, the time, and their velocity. The satellites are spaced so that fromany point on Earth, four satellites will be above the horizon

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• Each satellite contains a computer, an atomic clock, and a radio. With anunderstanding of its own orbit and the clock, it continually broadcasts its changingposition and time. Once aday, each satellite checks its own sense of time and positionwith a ground station and makes any minor correction.

• On the ground, any GPS receiver contains a computer that "triangulates" it sownpositionbythe form of a geographic position - longitude and latitude - to, for most receivers,within 100 meters.

• If the receiver is also equipped with a display screen that shows a map, the positioncan be shown on the map.

• If a fourth satellite can be received, the receiver/computer can figure out the altitudeas well as the geographic position.

• If you are moving, your receiver may also be able to calculate your speed anddirection of travel and give you estimated times of arrival to specified destinations.

  

Implementation of GIS for Land Use Inventory and Monitoring

 Major Activities:

• A methodology has been developed for land use mapping, planning, allocation and monitoring

• Land use mapping from aerial photographs and satellite images

• Priority areas have been mapped in 18 Provinces (approx. 3.85 Mio. ha)

• Development of national standards

• Development of quality monitoring schemes

• Training of staff has been carried out (approx. 800 staff members)

Problems:

• Integration in management and hierarchical structures

• The need for restructuring a part of the organisation (data flow, responsibilities, etc.)

• Technical overkill: pragmatic approaches are not considered

• Distance between technicians and planner

                               

GPS and GIS are powerful tools for environmental data analysis for land use planning and management. Below are some of the applicable areas where GIS can be implemented for effective land planning and management.

In practice, formal land registration has been undertaken of only a small proportion of Rwanda with the focus on urban areas and those in rural areas under commercial agriculture or owned by churches. The primary purpose is to provide land users with documentation of land holding, for legal purposes and as evidence of property rights as collateral for purposes of credit or mortgage. At present, the national land centre has decentralized its offices up-to the District level and each district has a land commission. Such structures do exist only in municipalities where decentralization of land survey and registration responsibilities have commenced to be carrying out with the overall follow up by the Ministry in charge of land.