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CEE 795 Water Resources Modeling and GIS. Session #1 (some material from Dr. David Maidment, University of Texas) January 18, 2006 Learning Objectives: Outline the various types of models that can be integrated with GIS Describe the geospatial database of hydrologic features
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CEE 795Water Resources Modeling and GIS Session #1 (some material from Dr. David Maidment, University of Texas) January 18, 2006 Learning Objectives: • Outline the various types of models that can be integrated with GIS • Describe the geospatial database of hydrologic features • Outline the Arc Hydro data model • Demonstrate the use of curved earth and a flat map projections Assignments: Get SCR login accounts Handouts:
Water Resources Modeling and GIS: Session 1 • Water Resource Models and GIS • Geospatial database of hydrologic features • Arc Hydro data model • Curved earth and a flat map
GIS and Hydraulic Models • HEC Geo-RAS • Used for Pre and Post processing of data from HEC-River Analysis System (RAS) • Open Channel flow model
GIS and Hydrologic Models • Automated Geospatial Watershed AssessmentTool (AGWA)
GIS and Water Distribution Models • Haestad WaterGEMS
Water Resources Modeling and GIS: Session 1 • Water Resource Models and GIS • Geospatial database of hydrologic features • Arc Hydro data model • Curved earth and a flat map
Geographic Data Model • Conceptual Model – a set of concepts that describe a subject and allow reasoning about it • Mathematical Model – a conceptual model expressed in symbols and equations • Data Model – a conceptual model expressed in a data structure (e.g. ascii files, Excel tables, …..) • Geographic Data Model – a conceptual model for describing and reasoning about the world expressed in a GIS database
Spatial Data: Vector format Vector data are defined spatially: (x1,y1) Point - a pair of x and y coordinates vertex Line - a sequence of points Node Polygon - a closed set of lines
Themes or Data Layers Vector data: point, line or polygon features
Kissimmee watershed, Florida Themes
Raster and Vector Data Raster data are described by a cell grid, one value per cell Vector Raster Point Line Zone of cells Polygon
Santa Barbara, California http://srtm.usgs.gov/srtmimagegallery/index.html
How do we combine these data? Digital Elevation Models Streams Watersheds Waterbodies
Data Model Based on Behavior “Follow a drop of water from where it falls on the land, to the stream, and all the way to the ocean.” R.M. Hirsch, USGS
Integrating Data Inventory using a Behavioral Model Relationships between objects linked by tracing path of water movement
Water Resources Modeling and GIS: Session 1 • Water Resource Models and GIS • Geospatial database of hydrologic features • Arc Hydro data model • Curved earth and a flat map
Arc Hydro: GIS for Water Resources Published by ESRI Press The Arc Hydro data model and application tools are in the public domain
Drainage System Hydro Network Flow Time Time Series Hydrography Channel System Arc Hydro Components
Hydrologic Information System Analysis, Modeling, Decision Making Arc Hydro Geodatabase
FLOODPLAIN MAP Nexrad Map to Flood Map in Model Builder Flood map as output Model for flood flow HMS Model for flood depth Nexrad map as input
Water Resources Modeling and GIS: Session 1 • Water Resource Models and GIS • Geospatial database of hydrologic features • Arc Hydro data model • Curved earth and a flat map
Origin of Geographic Coordinates Equator (0,0) Prime Meridian
Latitude and Longitude Longitude line (Meridian) N W E S Range: 180ºW - 0º - 180ºE Latitude line (Parallel) N W E S (0ºN, 0ºE) Equator, Prime Meridian Range: 90ºS - 0º - 90ºN
Latitude and Longitude in North America Austin: (30°N, 98°W) Logan: (42°N, 112°W) 60 N 30 N 60 W 120 W 90 W 0 N
Map Projection Flat Map Cartesian coordinates: x,y (Easting & Northing) Curved Earth Geographic coordinates: f, l (Latitude & Longitude)
Representative Fraction Globe distanceEarth distance = Earth to Globe to Map Map Projection: Map Scale: Scale Factor Map distanceGlobe distance = (e.g. 0.9996) (e.g. 1:24,000)
Coordinate Systems A planar coordinate system is defined by a pair of orthogonal (x,y) axes drawn through an origin Y X Origin (xo,yo) (fo,lo)