Coverage data model. Vector-Based Spatial Analysis: Tools Processes. Topological Data Model. Polygons Files. Geographic Information Systems.

Transcription

1 GEOG4340 Geographic Information Systems Lecture Four 2013winter Vector-Based Spatial Analysis: Tools Processes Reading materials: Chapter 6 of Intro GIS by J. R. Jensen and R.R. Jensen Cheng. Q., Earth and Space Science and Engineering, qiuming@yorku.ca Polygons Files Arcs Files Points Files Coordinate files Landuse.PAT Landuse.AAT Landuse.NAT Coordinate files Street.AAT Street.NAT Coordinate files Well.PAT Topological Data Model Feature attribute tables Point Attribute Table PAT Arc Attribute Table AAT Node Attribute Table NAT Polygon Attribute Table PAT Topological relationships Coverage data model A coverage is a data model for the storage of vector data. It generally represents a single set of geographic objects such as roads, parcels, soil units or forest stands in a given area. A coverage supports the georelational model it contains both the spatial (location) and attribute (descriptive) data for geographic features Label file Arc attribute tab Node attribute tab point locations Reference location

2 Shapefile data format Shapefile data format Shapefiles are a simple, non-topological format for storing vector data and attribute data. It generally represents a single set of geographic objects such as roads, parcels, soil units or forest stands in a given area. A shapefile does not support the georelational. Landuse.shp Landuse.shp Landuse.shx Landuse.dbf Landuse.dbf No shape id Map of same features Exchange file DBS file for attr. table Geodatabase Geodatabase of ArcGIS is object-based georelational spatial database. It works for storing vector data, attribute data and raster data. It generally represents multiple sets of geographic objects such as roads, parcels, soil units or forest stands in a given area and support the georelations among these sets Decision Spatial Analysis Support Knowledge Processes and Basic Tools Interpretation Information Processes GIS Database 2

3 Example of geoprocessing Create Buffer Zones Around Vectors Points Lines Polygons ArcGIS Operation Layer A Layer B Operator Layer C Operator Layer 3

4 Node -Node relationship Node -Line relationship Spatial Join Spatial Join Points B Line B New Attribute Showing nearest Points on B from A New Attribute Showing nearest Points on B from A Node -Polygon relationship Line -Line relationship Line A Spatial Join Table Join Points C By shape Line B New Attribute Showing class of ions 4

5 Line -Poly relationship Line -Poly relationship Line A Line A Line C Point C New line layer With lines separated According to poly Class in New Point feature Of intersect of Line A and Poly -Poly relationship Poly Poly Poly A Poly A Poly C Line C Identity Union New Poly combined Poly A and New Line Feature Common boundary of Poly A and Poly Poly Application and Vector-based Analysis Site for Wastewater Treatment Plant Poly A Point C New Point Feature of Poly A and 5

6 Model of Processes River Buffer R_Buffer Land Areas 6

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8 Parcel Select Residential Selected P Buffer 150m Res_Buf Park Buffer 150m P_Buffer Union Res_Park Flood_Z Union R_P_Flood 8

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