Xem mẫu

Analysis and Modeling in GIS 12/07/10 Ron Briggs, UTDallas GISC 6381 GIS Fundamentals 1 GIS and the Levels of Science Description: Using GIS to create descriptive models of the world --representations of reality as it exists. Analysis: Using GIS to answer a question or test an hypothesis. Often involves creating a new conceptual output layer, (or table or chart), the values of which are some transformation of the values in the descriptive input layer. --e.g. buffer or slope or aspect layers Prediction: Using GIS capabilities to create a predictive model of a real world process, that is, a model capable of reproducing processes and/or making predictions or projections as to how the world might appear. --e.g. flood models, fire spread models, urban growth models 12/07/10 Ron Briggs, UTDallas GISC 6381 GIS Fundamentals 2 The Analysis Challenge • Recognizing which generic GIS analytic capability (or combination) can be used to solve your problem: – meet an operational need – answer a question posed by your boss or your board – address a scientific issue and/or test a hypothesis Send mailings to property owners potentially affected by a proposed change in zoning Determine if a crime occurred within a school’s “drug free zone” Determine the acreage of agricultural, residential, commercial and industrial land which will be lost by construction of new highway corridor Determine the proportion of a region covered by igneous extrusions Do Magnitude 4 or greater sub-oceanic earthquakes occur closer to the Pacific coast of South America than of North America? Are gas stations or fast food joints closer to freeways? 12/07/10 Ron Briggs, UTDallas GISC 6381 GIS Fundamentals 3 Availability of Capabilities in GIS Software • Descriptive Focus: Basic Desktop GIS packages – Data editing, description and basic analysis – ArcView – Mapinfo – Geomedia • Analytic Focus: Advanced Professional GIS systems – More sophisticated data editing plus more advanced analysis – ARC/INFO, MapInfo Pro, etc. Provided through extra cost Extensions or professional versions of desktop packages • Prediction: Specialized modeling and simulation – via scripting/programming within GIS » VB and ArcObjects in ArcGIS » Avenue scripts in ArcView 3.2 » AMLs in Workstation ARC/INFO (v. 7) Write your own or download from ESRI Web site – via specialized packages and/or GISs » 3-D Scientific Visualization packages Capabilities move ‘down the chain’ over time. In earlier generation GIS systems, use of advanced applications often required learning another package with a different user interface and operating system (usually UNIX). » transportation planning packages e.g TransCAD » ERDAS, ER Mapper or similar package for raster Description and Basic Analysis (Table of Contents) • Spatial Operations Vector – spatial measurement – Centrographic statistics – buffer analysis – spatial aggregation » redistricting » regionalization » classification – Spatial overlays and joins Raster – neighborhood analysis/spatial filtering • Attribute Operations – record selection » tabular via SQL » ‘information clicking’ with cursor – variable recoding – record aggregation – general statistical analysis – table relates and joins – Raster modeling 12/07/10 Ron Briggs, UTDallas GISC 6381 GIS Fundamentals 5 ... - tailieumienphi.vn
nguon tai.lieu . vn