1. GIS Modeling Venkatesh Merwade, University of Texas at Austin Interdisciplinary aquatic modeling workshop, July 21, 2005

2. Overview GIS and data representation Geodatabase design Vector and surface analysis 3D and visualization in GIS GIS and Modeling Case studies

3. 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

4. Data Model based on Inventory of data layers

5. Vector Data (x 1, y 1 ) (x 2, y 2 ) (x 4, y 4 ) (x 3, y 3 ) Point – pair of (x,y) coordinates (x 2, y 2 ) (x 1, y 1 ) Line – a sequence of points Polygon – a closed set of lines All vector shapes (2D and 3D) are made from a set of points.

6. Vector Data for Guadalupe Basin in Texas Monitoring Points – USGS gaging stations Stream Network – Low resolution NHD Flowlines Watershed – 8 digit HUC units

7. Measure in ArcGIS A PolylineMZ can store m and z at each vertex along with x and y coordinates. 0 64.0056 112.3213

8. Raster Data 123456 123456 123456 123456 123456 123456 Number of columns Number of rows Cell Size Cell Cell Value Example, Digital Elevation Model

9. Raster  Vector Point Line Polygon VectorRaster Zone of cells

10. Triangulated Irregular Network Edge Node Face

11. How do we combine these data? Digital Elevation Models Watersheds Streams Waterbodies

12. An integrated raster-vector database

13. Overview GIS and data representation Geodatabase design Vector and surface analysis 3D and visualization in GIS GIS and Modeling Case studies

14. Geodatabase Design GeoDatabase (stores geographic data organized into datasets and feature classes ) Feature Dataset (collection of feature classes and relationship classes) Raster Catalog (a collection of raster datasets) Polyline Feature class Point Feature class Polygon Feature class Relationship class Object class

15. 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

16. Integrating Data Inventory using a Behavioral Model Relationships between objects linked by tracing path of water movement

17. Arc Hydro Data Model A geospatial and temporal data model for water resources HydroJunction HydroEdge Watershed Arc Hydro framework Personal Geodatabase Hydro Edge Hydro Junction Watershed Network Relationships Feature Dataset

18. Overview GIS and data representation Geodatabase design Vector and surface analysis 3D and visualization in GIS GIS and Modeling Case studies

19. Vector Analysis Attribute tools –Join/relate, calculations Topology and Network analysis –geometric networks and solvers Geo-processing –Batch processing of geometries

20. Attribute Relationships ReachHasCrossSections

21. Calculations using vector attributes Wshed 1Area = 2.47 CN = 71.64 PR = 32.20 Wshed 2 Area = 3.49 CN = 65.01 PR = 32.66 Wshed 3 Area = 23.30 CN = 68.70 PR = 32.51 1 2 3

22. Geometric Network Network Flag Geometric Network for Streams in Upper Guadalupe Trace Downstream Trace Upstream Find Path

23. Geo-processing

24. Surface analysis Raster Models –Perform simple algebraic calculations on raster cells Drainage Analysis using DEM –Flow direction, flow accumulation, watershed delineation

25. Runoff calculations Runoff, Q (mm/yr) Precipitation, P (mm/yr) P Q Cell by cell evaluations of mathematical functions

26. Pollutant Loading Estimation Load Mass = EMC * Runoff Runoff Load Computation of pollutant load (fecal coliform) to Galveston Bay in Texas.

27. Drainage Analysis 757779 8592 768073 8589 727581 8387 908583 7282 959089 8070 32 16 8 64 4 128 1 2 DEM Eight direction pour point model Flow Direction GridContributing areas and stream definition Stream Cell

28. Zonal Stats: Area, CN and PR

29. Overview GIS and data representation Geodatabase design Vector and surface analysis 3D and visualization in GIS GIS and Modeling Case studies

30. 3D Representation of MODFLOW Vertical dimension ~ 75 meters Each cell in the 2D representation is transformed into a 3D object (Multipatch) Control volume for the model domain Example from Savannah River in Georgia

31. 3D HydroElement

32. Rainfall and Streamflow Variations 29 hour duration, 15-minute interval

33. Tracking Fecal Bacteria in Galveston Bay

34. Overview GIS and data representation Geodatabase design Vector and surface analysis 3D and visualization in GIS GIS and Modeling Case studies

35. GIS and Modeling Loose coupling –Use GIS to extract input data and display output –Model runs independent of GIS Tight coupling –GIS and model are integrated in one system (eg. EPA Basins) Hydrologic Information Systems –Framework for coupling

36. Loose Coupling HEC-GeoRAS –GIS interface for HEC- RAS –cross-sections, reaches, bank-lines in GIS –Creates geometry files –Display Results in GIS

37. Tight Coupling GIS and model are integrated within one system (eg. EPA Basins) Tool development in GIS to simulate hydrologic processes –Dynamic Link Libraries –Code development –Must keep up with technology and model development

38. Hydrologic Information System Modeling Geodatabase A hydrologic information system is a combination of geospatial and temporal hydrologic data with hydrologic models that supports hydrologic practice, science and education

39. HMS IDM RAS IDM Interface data models HMS RAS GIS Geo Database Arc Hydro data model Connecting Arc Hydro and Hydrologic Models

40. Model Process Project Data Project Data Project Data Derived Data Derived Data Derived Data Tool (a)(c)(b) ArcGIS Model Builder

41. Overview GIS and data representation Geodatabase design Vector and surface analysis 3D and visualization in GIS GIS and Modeling Case studies

42. From a NEXRAD Map to a Floodplain Map Center for Research in Water Resources Component 2 Component 4 Component 1 Component 4 Component 3 Component 3: Floodmapping from HEC-RAS GIS SDF File DEMCross Sections with Water Surface Elevations Water Surface Raster Flood Inundation Polygon Component 2: Hydrologic & Hydraulic Integration based on common geographic framework Hydrologic Model HEC-HMS Hydraulic Model HEC-RAS Geographic Integration using Arc Hydro Watersheds Component 1: Importing NEXRAD data into Geodatabase and Mapping to Watersheds NEXRAD Data Component 4: Geodatabase to HEC-DSS to Geodatabase Time Series in Geodatabase Time Series in HEC-DSS HEC Data Storage System for Time Series FLOODPLAIN MAP Component 4 NEXRAD Rainfall Salado Creek, San Antonio Rosillo Creek Component 3: Creating a Flood Inundation Map Process Operations using Arc 9 Model Builder Research funded by The San Antonio River Authority

43. Fish Habitat Modeling Instream Flow Decision Making Hydrodynamic Model Habitat Descriptions Habitat Model GIS RMA2Biological Sampling Depth & velocity Species groups Criterion

44. Hydraulic and Biological Data Bathymetry Points Attribute Table Habitat Descriptions

46. Summary GIS can be used to store and visualize any type of data (geospatial and temporal) Geodatabase Model for storing Data Vector and surface analysis in GIS help accomplish data processing, parameter extraction and simple calculations Hydrologic Information Systems provides a way to integrate simulation models with GIS using a standard protocol

47. Questions Courtesy: Texas Water Development Board  David R. Maidment  Tim Whiteaker Thank you