Final review of EES6513 spring 2007 By Dr Hongjie Xie Assistant Professor at UTSA 4 19 2007 1 Review of basic GIS What is GIS 3 components computer system spatially referenced data people Spatially reference data or geographic data geospatial data attribute data metadata Geospatial data o Characteristics of spatial data mappable discrete or continuous spatial relationships o GIS is a simplified view of the real world discrete or continuous problems still exist dynamic and static identification of discrete or continuous features scale fuzzy o Topology adjacency containment or coincidence connectivity and how it works o Raster vector and geodatabase data models o GIS data or file formats vector shapefiles coverages TIN raster grid and image Geodatabase object oriented data model vector feature class feature datasets nonspatial table topology relationship classes geometric networks raster raster datasets raster catalogs Attribute data o row column relational database o one one many one one many many many join and relate Metadata Geodatabase personal and multi user 2 Spatial analysis vector analysis Two sets of vector analysis tools in ArcToolBox o For shapefile feature class table o For coverage Extract clip select split Overlay erase identify intersect union update Proximity buffer near point distance thiessen polygon 3 Spatial analysis raster analysis Spatial Analyst Tools includes groundwater and hydrology tools and Spatial Analyst extension Mapping distance straight line allocation function cost weighted distance shortest path mapping density surface analysis statistics cell neighborhood zonal reclassification raster calculator vector and raster conversion hydrology and watershed 4 Spatial statistics Spatial Statistics Tool for vector data and to help asses patterns trends and relationships Measuring geographic distribution where is the center analyzing patterns random clustered or dispersed Global calculations mapping clusters local calculations hot spot 5 Geostatistical analysis What is the geostatistical analysis Explore data why methods histogram voronoi map normal QQplot general QQPlot trend analysis semivariogram covariance cloud crosscovariance cloud Methods of interpolation global and local deterministic and geostatisctical exact and inexact nodirectional and ansotropy 1 IDW characteristics 2 Global polynomial 3 Local polynomial 4 Radial Basis Functions or spline 5 Kridging assumption assessment of prediction errors Ordinary universal simple indicator cokridging Output maps prediction map standard error map quintile map probability map Cross validation and validation Basic rules for good predictions 1 mean error 2 RMS prediction error average standard error mean standardized error 3 RMS standardized error 4 average standard error vs RMS prediction error 5 RMS standardized error 1 1 1 6 3D analysis Difference between 3D and 2D data 3D analyst include ArcScene and ArcGlobe which used for visualizing 3D data creating and analyzing 2D and 3D surfaces Type of 3D data o 3D surface raster and TIN o 3D feature shapefile and geodatabase feature class has a field of PointZ PolygonZ PolylineZ in the attribute table o Create TIN from vector data point lines polygons o Mass points are nodes from which triangles are constructed o Breakline tell a distinct change hard breakline capture abrupt changes in a surface soft breakline do not affect the shape of the surface o Replace clip erase fill polygons Create 3D feature o convert 2D to 3D or o define a new empty 3D feature then digitize from a 3D raster or TIN Convert TIN to features o Slope and aspect polygon features elevations of nodes as point feature ArcScene o Scene properties vertical exaggeration animated rotation background color extent and illumination azimuth and sun elevation o Layer property base heights the z value could be elevation population precipitation temperature and extrusion point to line line to wall polygon to block 7 Geoprocessing Is the center of GIS most every processing in GIS we performed is a Geoprocesing Definition a GIS operation that takes one or more input datasets performs one or more operations returns one or more output layers results o Four ways dialog tool box command line model script o Model is a workflow chart that can execute multiple processes as one operation share your idea with others o Script a text file contains instructions for geoprocessing of code batch processing model builder o interactive window used to create models inside of ArcGIS data connector and tools python script o Every element in ArcMap is actually a ArcObject ArcGIS is built with a set of ArcObjects o Each ArcObject has properties and methods o Python script based on the ArcObjects through ArcObjects COM objects you can access geoprocessor its peroperties and methods or ArcObects peroperties and methods