Watershed and Stream Delineation Tool for ArcGIS 8.1
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Transcript of Watershed and Stream Delineation Tool for ArcGIS 8.1
Watershed and Stream Delineation Tool for
ArcGIS 8.1
Watershed and Stream Delineation Tool for
ArcGIS 8.1By Milver A. Valenzuela
TEXAS A&M UNIVERSITY
IntroductionIntroduction
What is ArcGIS 8.1?
What is new on ArcGIS 8.1?
ArcGIS 8.1ArcGIS 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.
ArcView 8.1ArcView 8.1
Arc View 8.1
ArcCatalog ArcMap ArcToolbox
EditShapefilesGeodatabases
Extensions
ArcGIS 8.1ArcGIS 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
What is COM?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++.
What is COM?What is COM?
Component Object Model
Client ServerInterfaces
Interfaces
Interfaces
Interfaces
What is COM?What is COM?
Component Object Model
Interfaces
Properties Methods
The ToolThe Tool
Developed in VBA(GIS).
Follows a simple linear procedure.
From a simple input it can be delineated watersheds.
The ProcedureThe Procedure
INPUT
Procedure
Output
The InputThe Input
Digital Elevation Model
Threshold number
Output directory
The ProcedureThe Procedure
Fill sinks Flow Direction Flow Accumulation Threshold condition Grid Streams Grid Watersheds Vectorization of Streams Vectorization of Watersheds
The OutputThe 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)
An Example: 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
The DEM The DEM
The InterfaceThe Interface
The Output: Filled DEMThe Output: Filled DEM
The Output: Flow Direction GridThe Output: Flow Direction Grid
The Output: Flow Accumulation GridThe Output: Flow Accumulation Grid
The Output: Streams GridThe Output: Streams Grid
The Output: Links GridThe Output: Links Grid
The Output: Watershed GridThe Output: Watershed Grid
The Output. Vectorized streams and watershedsThe Output. Vectorized streams and watersheds
File system output File system output
Limitations 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.
The next step… The next step…
Add an “advance” button as well as more features.
Convert the program to dll.
Questions & CommentsQuestions & Comments