Application of remote sensing technique in biomass change detection: a case study of Bromley and Chihota, Zimbabwe

Biomass is defined as the total mass of living plant matter in a given unit of an environment area.  Several factors influence the change in biomass content of an area. The rate of change varies from mass seasonal drying of grasslands to gradual degradation of forestry area.  It is in the interest of environmental monitoring and sustainable development that biomass change be constantly determined. There are various field methods used worldwide to determine density of forest resources but have several limitations because of the nature of factors influencing biomass change.  These include seasonal changes, human activities, forest fires etc.  Remote Sensing as an enabling technology provides an efficient avenue of assessment of biomass content of any area.  This research focused on biomass content that constituted forest resources. Two main methods used were qualitative analysis involving visual image interpretation relying on knowledge of spectral reflectance characteristics of ground cover types and quantitative analysis involving use of mathematical capacity of the computer to extract information on pixel digital number The techniques employed in these methods were complementary and were combined in a systematic manner to optimize the potential of remotely sensed data in biomass change. Comparison of two methods information, revealed that biomass content obtained from the remotely sensed data from the two study areas were almost identical. Extra ancillary data like population information and detailed land use data, can be integrated into GIS together with results from remote sensing analysis to enhance the decision making process.Keywords:  Biomass, Forest, Image, Interpretation, Qualitative, Quantitativ

A comparison of Google Earth extracted points with GPS surveyed points

Surveying has become the most effective way of taking measurement in or/and on the earth surface. There is an exponential rise in techniques of taking measurements on the earth for different reasons and purposes. Google Earth offers an open source service, easy to access and cost free image data that supports map interests and provides data which are crucial for engineering purposes. Google earth has become so popular not because of its high accuracy, but because it is easily accessible to anyone. Google Earth, virtual globe uses World Geodetic Coordinate System 1984 WGS84 as a global coordinate system. However, in this research, the transformations made from those data obtained using Global Positioning Systems (GPS) and those obtained from Google Earth were made and analyzed. The same points were uploaded to Global Positioning Systems and Google Earth for extraction of heights. The resultant coordinate generated contours obtained from both systems were analyzed and conclusions made. The height difference obtained from both system was 15.138m

Mapping wetland characteristics for sustainable development in Harare: The case of Borrowdale West, Highlands, National Sport stadium and Mukuvisi Woodlands wetlands

Wetland ecosystems are under threat from agriculture and urbanisation, affecting water supply and quality in urban areas like the City of Harare. With the need to protect wetlands that remain, the spatial extent of the Highlands, Borrowdale West, Mukuvisi and National Sports wetlands was established. LANDSAT and SPOT Satellite imagery were used to map the spatial extent on the wetlands and to take note of the temporal changes that occurred between 1989 and 2009. Supervised classification was used to classify the images. High resolution Google earth imagery were then downloaded and used as baseline data for mapping the wetlands using the Cowardin wetland classification system 1979 and the Land Capability Classification system for wetness. Maps showing the physical characteristic of the wetlands were then produced. Results indicated that area under wetlands has been shrinking over the years. Using the wetland classification system it was found out that much of the area under wetland should not be used for any other landuse purpose other than wetland protection. However the study found out that urban expansion projects are currently modifying the wetlands. The Highlands wetland has been drained and road construction is currently in progress while a Hotel is under construction on the National sports wetland covering 287 012 m2 of the wetland. This study provides information on the current physical state of the wetlands, which can be the basis for wetland protection and management by policy makers and managers. Key Words:  Wetland, Spatial extent, Physical characteristics, Classification, Landuse, Protection and Managemen

A spatially based field specific crop recordkeeping system prototype for farmers

The purpose of this study was to develop a spatially based application that is able to capture, query, update and maintain crop production historical records for each field. Maps of the farm showing the fields were made. The fields were then numbered. These spatial data were prepared using ArcGIS 9.3. A database was created in Microsoft Access 2007. The database contained information on crops, fertilizers and past management. The information was linked to the spatial data table and maintained in the database. An application was developed using Visual Basic 6 in Map Objects allowing for the manipulation of spatial data within the visual basic environment. Results have shown that a record keeping system may link crop records to respective mapped crop fields in a GIS environment. This was then used to view crop field area, update new field data in the non spatial database and query and display field data for a specified period of interest. New data were added to their respective tables whenever available.Keywords:  Recordkeeping system, Crop field, spatial, Farm, Management, Applicatio

Mapping Suitable Sites for Setting up Wind Farms: A Case Study of Nyanga District

Due to the negative impacts on the environment of traditional power-generating methods, especially fossil fuels, wind power has increased in popularity. Achieving carbon emissions reduction goals due to the implementation of the Kyoto Protocol require exploitation of renewable energy, Cleaner Development Mechanisms, (CDM). Additionally, the increased difficulty of obtaining oil from foreign sources and continuous power shortages make wind energy a very attractive alternative to keep Zimbabwe powered, clean and green. In order to tap the potential of wind energy sources, there is a need to assess the spatial availability of the resources. Mapping suitable sites for setting up wind farms was the focus of this study. The study employed the Geographical Information Systems (GIS) approach to map the wind energy resources of Nyanga district and carry out a multi-criteria evaluation analysis of their potential by considering other data sets such as land cover, land use and proximity to roads. From the analysis carried out, the mean area size of the most suitable land parcels was 36.810 km2,which is therefore more than enough for a large wind farm given that an area size of 2 km2 is enough to justify the development of a 10MW wind farm project. Most suitable areas were found where commercial activities are while small patches averaging 5 to 10 km2 in rural areas make the medium suitability areas.Key Words: Mapping, Sites, Wind farm, Energy, Multi-criteria, Evaluatio

Visualization of temporal aspects of tsetse fly eradication in Zimbabwe on the web

Visualization of tsetse eradication operations that have been going on since early 20th century is what many people would like to do if possibilities are provided. In this assignment, available data are analysed and viewed in the three tsetse eradication programmes. Zimbabwe is divided into three area categories; infested, reclaimed and pre 1896 tsetse free zone. Information on where eradication operations were carried out and the technologies that were applied for each year were extracted and mapped within its operation programme. Technologies applied were viewed individually and their positions compared with the fronts before and after they were applied. Pattern of how they are applied in time was provided in the animation representation. Further information on areas where different techniques were applied on different years is interactively visualized. Visualization of infestation changes in time was also provided by animation representation. Visualization of eradication operations were disseminated on the web. From the available data, it was possible to visualize Zimbabwe in three distinct categories: infested, reclaimed and the area that had never been occupied by tsetse flies. Visualization of tsetse fly eradication processes was possible in three sections that identified the sequence of eradication. It has been possible to visualize the change in technology in terms of techniques used.  Accessibility of tsetse fly eradication was provided by the web.Key Words: Visualization, Tsetse fly, Eradication, Infested, Reclaimed, Disseminat