microclimate

microclimate

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  ASSIGNMENT 02 1. Definespatial and attributes 1. Spatial data Spatial data describes the absolute andrelative location of geographic features. Attributes data Attribute data describes characteristicsof the spatial features. These characteristics canbe quantitative and/or qualitative in nature, Attribute data is often referred to as tabular data. 2. Difference between a vector and raster and their advantages and disadvantages A raster image- is made of up pixels, each a different colour, arranged to display an image. A vector image- is made up of paths; each with a mathematical formula (vector) that tells the path how it is shaped and what colour it is bordered with or filled by. Advantages and disadvantages of vector and raster Advantages of vector Data can be represented at its original resolution and form without generalization. Graphic output is usually more aesthetically pleasing (traditional cartographic representation); Since most data, e.g. hard copy maps, is in vector form no data conversion is required. Accurate geographic location of data is maintained. Allows for efficient encoding of topology, and as a result more efficient operations that require topological information, e.g. proximity, network analysis. Disadvantages of vector The location of each vertex needs to be stored explicitly. For effective analysis, vector data must be converted into a topological structure. This is often processing intensive and usually requires extensive data cleaning. As well, topology is static, and any updating or editing of the vector data requires re-building of the topology. Algorithms for manipulative and analysis functions are complex and may be processing intensive. Often, this inherently limits the functionality for large data sets, e.g. a large number of features. Continuous data, such as elevation data, is not effectively represented in vector form. Usually substantial data generalization or interpolation is required for these data layers. Spatial analysis and filtering within polygons is impossible Advantages of raster The geographic location of each cell is implied by its position in the cell matrix. Accordingly, other than an origin point, e.g. bottom left corner, no geographic coordinates are stored.
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  Due to thenature of the data storage technique data analysis is usually easy to program and quick to perform. The inherent nature of raster maps, e.g. one attribute maps, is ideally suited for mathematical modelling and quantitative analysis. Discrete data, e.g. forestry stands, is accommodated equally well as continuous data, e.g. elevation data, and facilitates the integrating of the two data types. Grid-cell systems are very compatible with raster-based output devices, e.g. electrostatic plotters, graphic terminals. Disadvantages of raster The cell size determines the resolution at which the data is represented. It is especially difficult to adequately represent linear features depending on the cell resolution. Accordingly, network linkages are difficult to establish. Processing of associated attribute data may be cumbersome if large amounts of data exist. Raster maps inherently reflect only one attribute or characteristic for an area. Since most input data is in vector form, data must undergo vector-to-raster conversion. Besides increased processing requirements this may introduce data integrity concerns due to generalization and choice of inappropriate cell size. Most output maps from grid-cell systems do not conform to high-quality cartographic needs. 2 Different spatial data objects in GIS environment *Points represent anything that can be described as a discrete x, y location *Lines represent anything having a length *Areas, or polygons, describe anything having boundaries These data types comprise the vector model, which is the model you will deal with most often in GIS. Vector data model: Discrete features, such as customer locations, are usually represented using the vector model. Features can be discrete locations or events, lines, or areas. Lines, such as streams or roads, are represented as a series of coordinate pairs. Areas are defined by borders, and are represented by closed polygons. When you analyze vector data, much of your analysis involves working with (summarizing) the attributes in the layer's data table. Raster data model: Continuous numeric values, such as elevation, and continuous categories, such as vegetation types, are represented using the raster model. The raster data model represents features as a matrix/lattice of cells in continuous space. A point is one cell, a line is a continuous row of cells, and an area is represented as continuous touching cells.
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  Tabular data Containinformation describing a map feature in the form of a table or spread sheet. For example, a GIS database of customer locations may be linked to address and personnel information. GIS links this tabular data to associated spatial data. The major difference is that raster image pixels do not retain their appearance as size increases – when you blow a photograph up, it becomes blurry for this reason. Vector images do retain appearance regardless of size, since the mathematical formulas dictate how the image is rendered A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet (for example a garden bed) or as large as many square miles (for example a valley). Microclimates exist, for example, near bodies of water which may cool the local atmosphere, or in heavily urban areas where brick, concrete, and asphalt absorb the sun's energy, heat up, and reradiate that heat to the ambient air: the resulting urban heat island is a kind of microclimate. Another contributing factor to microclimate is the slope or aspect of an area. South-facing slopes in the Northern Hemisphere and north-facing slopes in the Southern Hemisphere are exposed to more direct sunlight than opposite slopes and are therefore warmer for longer. The area in a developed industrial park may vary greatly from a wooded park nearby, as natural flora in parks absorb light and heat in leaves, that a building roof or parking lot just radiates back into the air. Advocates of solar energy argue that widespread use of solar collection can mitigate overheating of urban environments by absorbing sunlight and putting it to work instead of heating the foreign surface objects.[citation needed] A microclimate can offer an opportunity as a small growing region for crops that cannot thrive in the broader area; this concept is often used in permaculture practiced in northern temperate climates. Microclimates can be used to the advantage of gardeners who carefully choose and position their plants. Cities often raise the average temperature by zoning, and a sheltered position can reduce the severity of winter. Roof gardening, however, exposes plants to more extreme temperatures in both summer and winter. Tall buildings create their own microclimate, both by overshadowing large areas and by channelling strong winds to ground level. Wind effects around tall buildings are assessed as part of a microclimate study. Microclimates can also refer to purpose made environments, such as those in a room or other enclosure. Microclimates are commonly created and carefully maintained in museum display
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  and storage environments.This can be done using passive methods, such as silica gel, or with active microclimate control devices Disadvantages for GIS use in the government There are some disadvantages to using GIS in a government setting. Possible concerns include
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  the idea thatGIS decreases the democratic right of the people or that the technology is taking power away from the masses and into the hands of a few because only a limited number of people know how to use the technology. This is true to some extent. First, costs for GIS software and powerful computers to operate it are decreasing; however the costs of producing high- quality data are increasing [35]. Companies who produce data can charge high prices, and the cost of hiring staff to generate data on site can be expensive as well. Therefore, many cities or small local governments could afford the computers and necessary software but creating the data suitable to their individual needs may be out of reach. The costs of using GIS once the data have been collected and created are minimal; however, the initial building phase involves a significant investment from the agency [102]. CONCLUSION A Data Input A data input subsystem allows the user to capture, collect, and transform spatial and thematic data into digital form. The data inputs are usually derived from a combination of hard copy maps, aerial photographs, remotely sensed images, reports, survey documents, etc. Data Storage and Retrieval The data storage and retrieval subsystem organizes the data, spatial and attribute, in a form which permits it to be quickly retrieved by the user for analysis, and permits rapid and accurate updates to be made to the database. This component usually involves use of a database management system (DBMS) for maintaining attribute data. Spatial data is usually encoded and maintained in a proprietary file format. Data Manipulation and Analysis
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  The data manipulationand analysis subsystem allows the user to define and execute spatial and attribute procedures to generate derived information. This subsystem is commonly thought of as the heart of a GIS, and usually distinguishes it from other database information systems and computer- aided drafting (CAD) systems. Data Output The data output subsystem allows the user to generate graphic displays, normally maps, and tabular reports representing derived information products. The critical function for a GIS is, by design, the analysis of spatial data. 5.1 Education Education is a field where integration of multimedia and GIS can bring enormous benefits. Students will learn faster and more efficiently. In addition, it will be possible to individualize learning and tune it to particular preferences of each student. In this model a teacher becomes a guide rather than a repository of facts. It is the computer that takes on a role of "an infinitely patient teacher." 5.2 Mapmaking GIS can use and combine all layers that are available for an area, in order to produce an overlay that can be analyzed by using the same GIS. Such overlays and their analysis radically change decision-making process that include, among others: • Site selection • Simulation of environmental effects (for
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  example, creating perspectiveviews of a terrain before and after mining) • Emergency response planning (for example, combining road network and earth science information to analyze the effects of a potential earthquake) 5.3 Land Information GIS has aided management of land information by enabling easy creation and maintenance of data for land records, land planning and land use. GIS makes input, updates, and retrieval of data such as tax records, land-use plan, and zoning codes much easier then during the paper-map era. Typical uses of GIS in land information management include managing land registry for recording titles to land holdings, preparing land-use plan and zoning maps, cadastral mapping etc. Input of data into a land information GIS includes: politicaladministrative boundaries, transportation, and soil cover. 5.5 Environmental The environmental field has long used GIS for a variety of applications that range from simple inventory and query, to map analysis and overlay, to complex spatial decision-making systems. Examples include: forest modeling, air/water quality modeling and monitoring,
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  environmentally sensitive zonemapping, analysis of interaction between economic, meteorological, and hydrological & geological change. Typical data input into an environmental GIS include: elevation, forest cover, soil quality and hydrogeology coverage. 5.6 Archaeology Archaeology, as a spatial discipline, has used GIS in a variety of ways. At the simplest level, GIS has found applications as database management for archaeological records, with the added benefit of being able to create instant maps. It has been implemented in cultural resource management contexts, where archaeological site locations are predicted using statistical models based on previously identified site locations. It has also been used to simulate diachronic changes in past landscapes, and as a tool in intra-site analysis 5.7 Natural Hazards Areas vulnerable to earthquakes, floods, cyclones, storms, drought, fire, volcano, land slides, soil erosion can be used to accurately predict future disasters. 5.8 Forestry GIS has been emerging as a strong tool for many areas of forestry, from harvesting
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  schedules to urbanforestry. 5.9 Military GIS GIS offers a virtually unique ability to aggregate, automate, integrate and analyze geographical data, which further enhance the intelligence base for defense operations 5.10 Oceanography GIS enables study of sea level change, marine population, sea surface temperature, and coral reef ecosystem 5.11 Water Resources GIS enables spatial representation of ground water resources, waste quality, watershed management, surface water management, and water pollution. 5.12 GIS in agriculture and soil Data includes information on the country’s land resources including physiography, soils, climate, hydrology, cropping systems and crop suitability. 6 Currently available GIS software Some of the big players providing GIS software are: • ESRI’s ArcGIS: ArcGIS is a scalable system for geographic data creation, management, integration, analysis, and dissemination.
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  • Autodesk’s AutoCADMap: This software is for precision mapping and geographic information system (GIS) analysis in the AutoCAD environment. It has the special tools needed to create and produce maps and geographic information—plus all the underlying functionality of AutoCAD. • Autodesk’s GIS design overlay: Autodesk GIS design overlay combines powerful server technology with the mapping and design capabilities of AutoCAD Map®, enabling access to enterprise geographic and design data via desktop, web, and mobile client technology. • Intergraph’s GeoMedia Transportaion