1. Watershed and Stream Delineation Tool for ArcGIS 8.1 By Milver A. Valenzuela TEXAS A&M UNIVERSITY

2. Introduction What is ArcGIS 8.1? What is new on ArcGIS 8.1?

3. ArcGIS 8.1 The three desktop GIS components of ArcGIS are: ArcView :composed by ArcMap, ArcCatalog and ArcToolbox. ArcEditor: same as ArcView but with capacities for editing coverages and geodatabases. ArcInfo: same as ArcEditor plus capacities for geoprocessing and with a full version of ArcInfo Workstation.

4. ArcView 8.1 ArcCatalogArcMapArcToolbox Edit Shapefiles Geodatabases Extensions

5. ArcGIS 8.1 Top ten features shared by ArcInfo, ArcView, and ArcEditor Advanced editing tools High-quality cartography Internet-enabled On-the-fly projection Geocoding Wizard-driven tools Support for metadata standards using XML COM-based customization Extensible architecture Direct read of more than 40 data formats COM-based customization

6. What is COM? Component Object Model It’s a technology developed by Microsoft Corporation. COM establishes a common way of building software components. Because of these, it can be written macros in VBA(GIS) or extensions in VB, Delphi and C++.

7. What is COM? Component Object Model Client Server Interfaces

8. What is COM? Component Object Model Interfaces PropertiesMethods

9. The Tool Developed in VBA(GIS). Follows a simple linear procedure. From a simple input it can be delineated watersheds.

10. The Procedure INPUT Procedure Output

11. The Input Digital Elevation Model Threshold number Output directory

12. The Procedure Fill sinks Flow Direction Flow Accumulation Threshold condition Grid Streams Grid Watersheds Vectorization of Streams Vectorization of Watersheds

13. The Output The following layers: Filled DEM (fdem) Flow Direction Grid (fdr) Flow Accumulation Grid (fac) Streams Grid (str) Links Grid (lnk) Watersheds Grid (wsh) Vectorized streams (strl) Vectorized watersheds (wshp)

14. An Example: Delineating watersheds and streams for the Guadalupe River Basin. (Similar exercise done with CRWR-PrePro in class) DEM: Guadalupe River Basin derived from USGS 15” of the United States (500m cell size), UTM projection. Threshold: 500 cells: 500x500mx500m as minimum drainage area

15. The DEM

16. The Interface

17. The Output: Filled DEM

18. The Output: Flow Direction Grid

19. The Output: Flow Accumulation Grid

20. The Output: Streams Grid

21. The Output: Links Grid

22. The Output: Watershed Grid

23. The Output. Vectorized streams and watersheds

24. File system output

25. Limitations The process is irreversible. We can’t save other output in the same workspace because the names of the files are fixed. It gives an automation error. The program doesn’t have an specific error handler.

26. The next step… Add an “advance” button as well as more features. Convert the program to dll.

27. Questions & Comments