Geographic Information Data, Analysis & Representation

Transcription

1 Geographic Information Data, Analysis & Representation Michaela Kinberger University of Vienna Department of Geography and Regional Research N E Geographic Phenomena Types of Geographic Phenomena Something of interest that can be described can be georeferenced can be assigned a time (interval) at which it is/was present Field Continuum For every point in the study area a value can be determined e.g. elevation, temperature Object Populate the study area Well distinguishable, discrete, bounded entities Space between objects is empty e.g. building, road Characteristics of Spatial Data Spatial Spatial reference (geographic location, coordinates) where? Attributes (non-spatial) what? Spatial Spatial relationships (topology, metric, order) in what relationship? Temporal component (different concepts of time) when? Geographic Information System Combination of hardware, software, geo- data and brainware Main Main stages of data processing: Data entry Data management Data analysis Data representation

2 Raster Data Representation Vector Spatial Reference Coordinate Systems Geographic Coordinates (Lattitude, Longitude) Geocentric Coordinates (X,Y,Z) Local (planar) coordinate systems Spatial Reference Map Projection: A map projection allows to represent the three- dimensional curved surface of Earth on planar media (e.g. Sheet of paper, Computer Monitor) Topology Describes the neighborhood and spatial relations of arcs, polygons and points Characteristics of map projections: Equivalence Equidistance Conformal projection Different geometry, same topology IsIs data about data Metadata DescribeDescribe content and characteristics of data (Quality of positions and attributes, completeness, timeliness, spatial reference, ) Spatial Management Relational databases (Oracle, PostgreSQL) SpatialSpatial extension (Oracle spatial,, Postgis) Distributed Database

3 Digital Digital geodata Terrestrial surveys GPS GPS Photogrammetry RemoteRemote sensing MapsMaps Data Sources Gtopo30 Gtopo30 Freely available geodata edc.usgs.gov/products/elevation/gtopo30/gtopo30.html SRTM srtm/ SRTM Digital Digital Chart of the World USGS edc.usgs.gov/geodata/ USGS Digitizing and Modeling Real World Modelling Objects Data Modelling Digital Modell Kainz(2004)

4 Analysis - Raster Analysis - Raster Analysis - Raster SlopeSlope AspectAspect Viewshed Other Other Calculations

5 Information query Analysis - Vector Analysis / Spatial Modelling - Vector Intersections Measurements Interpolation BufferingBuffering Network Analysis Open Source GIS Low costs Free availability Good Usability Active Communities Readable and extendable source code Open Source Software Programming languages C-Tree: UMN-Mapserver Mapserver,, GRASS, GDAL/OGR, OSSIM, Proj4, Geos, PostGIS.. Java-Tree: GeoServer, GeoTools,, JTS, Jump/CS, DeeGree Software and Libraries in C Quantum GIS OpenEV OSSIM GRASS PostGIS GEOS OGR/GDAL Vector Vector Formats: PostGis, Shapefiles, Mapinfo,, OGR, GRASS, GPSeXchange Raster Raster Formats: GeoTiff, Tiff,, USGS DEM, ArcInfo,, ERDAS, SDTS, DTED, GRASS Mapserver Thuban Proj4 GMT

6 Materials provided for the Mountain-Risk Workshop Kempten, 15th 22nd June Open Source GIS Internet Sources Software Repositories freegis.org, freegis.org, opengis.org GRASS GIS grass.itc.it Jump References Geographic Information Data, Analysis & Representation Michaela Kinberger University of Vienna Department of Geography and Regional Research Riedl D., Riedl A. (2008): Einfü Einführung in die Geoinformation. Lecture notes, notes, University of Vienna, Vienna, Department of Geographie and Regeonal Resarch. Resarch. Kainz W. (2004): Geographic Information Science (GIS). Lecture notes, notes, University of Vienna, Vienna, Department of Geographie and Regeonal Resarch. Resarch.