PLAN281 Lecture Notes - Lecture 9: Digitizing, Photogrammetry, Differential Gps
27 May 2016
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Document Summary
Data = foundation of a gis installation. Data determines: what you can analyse. Issues and problems: where your analysis focus on, study area, types of analysis, e. g. Access to high quality, geo-referenced data is often difficult: historical data collection often no locational dimension, problems with converting existing paper maps, digital data may exist but confidentiality, liability, or commercial interests may disallow broad use. In the past, data construction often said to consume up to 3 4 of gis project budget and time: labour-intensive, error-prone, can become an end" in itself! One of the most expensive gis activities. Two broad data capture methods: primary (direct measurement, secondary (indirect derivation) Secondary existing data: already published/available, special tabulation/contract. Administrative records data as by-product: within your organization, other organizations. Primary data from scratch: developed in-house diy, contracted out, primary data capture. : spot and ikonos satellites and aerial photography: passive and active sensors. Resolution is key consideration: spatial, spectral, temporal.
