chap2 imp - Data Capture and Automation Sources of...

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Data Capture and Automation
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Analogue data Digital data Sources of Geographic Data
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While modelling is what a GIS is most often used for, it would be impossible to obtain results without a reliable database. You must create the database from geographic source data. Sources of geographic data are generally available in two forms. Analog data – a physical product displaying information visually on paper or film Digital data formatter or a computer Sources of Data
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Analog : a number of different sources are available Standardised map sheets Mylar map transparencies Air photos Written reports Digital : There are number of different data sets and they can be purchased. A few of the sources are listed below DEM – Digital Elevation Model, files from the US Geological Survey (Elevation Data) Digital satellite data can be obtained at different resolutions from various sources Other data can be obtained in digital format such as DXF or SIF data files, which are generated by other software A GIS must be able to accept a wide range of formats and kinds of data. Time, money, accuracy, and suitability should be considered while deciding how much of your database you create in-house and how much you obtain in existing digital form. Creating a database will consume a substantial portion of an initial GIS budget and database maintenance should be considered in any proposed GIS budget.
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Satellite Remote Sensing Scanning Digitizing GPS Aerial Photography Data Capture
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Introduction The functionality of GIS relies on the quality of data available, which, in most developing countries, is redundant or inaccurate. Although GIS is being used widely, effective and efficient means of data collection have yet to be systematically established. The true value of GIS can only be realised if the proper tools to collect spatial data and integrate them with attribute data are available. There are varieties of that possible for capturing spatial data namely: Manual Digitization Key Punching Global Positioning System Remote Sensing Scanning Data Capture
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What is a Map? Provide descriptions of geographic phenomena Spatial and non-spatial information Map Features Point Line Polygon Map Properties Scale Resolution Accuracy Precision
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What is a Map? Maps have been used since the earliest times to portray information about the earth's surface. A map is also an information system, normally representing on a certain scale and on a flat medium a selection of material or abstract features on, or in relation to, the surface of the earth. Maps have been used over the centuries to portray geographic information. In the twentieth century, the pace of science and technology accelerated. This increase in pace created a demand for ever greater volumes of geographic data to be presented in a map form more quickly and more accurately. With the development of reconnaissance technologies, such as aerial photography
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chap2 imp - Data Capture and Automation Sources of...

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