Lecture-5_Bb_1SlidePerPage

Lecture-5_Bb_1SlidePerPage - GIS Data Collection &...

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GIS Data Collection & Metadata
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Data Collection • The process of ________ geographic data to a database; • Many diverse sources for GIS data , categorized into two broad types: – ________ : captured specifically for use in GIS by direct measurement – ________ : reused from earlier studies Raster Vector ______ Digital remote sensing images GPS measurements Digital aerial photographs Survey measurements ______ Scanned maps or Orthos Topographic surveys DEMs from maps Toponymy (place name) database
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Data Collection Data collection is one of most expensive of all GIS activities Data maintenance may be more complex and expensive, for a multi-year project period, than the original collection activity – Dependant upon how regularly the dataset requires ___________ Costs for a typical client- server GIS implementation 10 Seats 100 Seats $ (1000) % $ (1000) % Hardware 30 3.4 250 8.6 Software 25 2.8 200 6.9 Data 400 44.7 450 15.5 Staff 440 49.1 2000 69.0 Total 895 100 2900 100
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Data Collection Stages ___________ ___________ ______________ _______________ ___________ •Establish user requirements •Acquiring resources (Staff, Hardware, etc.) •Develop a project plan •Obtaining data •Manipulating That Data Prior To Entry (Removing Noise, etc.) •Setting Up Hardware Majority Of All Efforts •Table digitizing •Survey entry •Vectorization •Validate data •Ensure Topology, Attributes, etc. •Correct Any Errors •Assess project success or failure •Particularly following a pilot study
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Primary Data Capture • The direct ___________ of objects, – May be directly inputted into a GIS or stored in a file – Raster data capture • The most popular form is ___________ ___________ – The measurement of physical, chemical, and biological properties of objects without direct contact – Satellite Imagery or aerial photography
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Primary Data Capture • Raster data capture (Cont.) – ___________ is key consideration • _______ : the size of objects that can be resolved, pixel size – Satellite image: 0.6m-1km (app. 2-3000’); – Aerial photo: 0.1 - 0.6m (app. 4-24”) • _______ : the parts (bands) of electromagnetic spectrum measured • _______ : the frequency with which images are collected for the same area
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Primary Data Capture • Raster data capture (Cont.) – The pros/cons of remote sensing
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Lecture-5_Bb_1SlidePerPage - GIS Data Collection &...

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