Slide 1

Report
Introduction
to GIS
Watershed Discretization
(model elements)
+
Digital
Elevation
Model (DEM)
Geographic
Information
System
Intersect model
elements with
Soil
Land
Cover
Rain
Results
Geographic Information
System
A spatially referenced database for
storing, retrieving, transforming and
displaying information
Hammer
A tool meant to deliver an impact to
an object.
Components of Geographic Database
Input
Database
GEOGRAPHIC DATABASE
Query
input
Attributes
Topology
Position
Management Systems
Retrieval
Transformation
Data Input
Existing maps
Interactive terminal
Field observation
Digitizer
Text file
INPUT DATA
Sensors
Scanner
Magnetic media
Data Output
Displaying and
Reporting
Visual
Display
Terminal
MAPS
Printer
Plotter
TABLES
Magnetic
Media
FIGURES
Data Types
Cells,
Pixels
Points, Lines,
Polygons
Geographic Information Systems
Basic Concepts
PC/Workstation
Topography Roads
Soil
Map
Land
cover
Color IR
Manual
encoding
Coordinate
digitizer
Data
Graphics/color
printer output
image
manipulation
Monitor
Plotter
CD
Hard
Disk
Video or
array
scanner
Drum or
laser
scanner
Data Input
Floppy
disk
Data storage
Film
recorder
Data output
Hydrologic Modeling
Data Model
based on
Inventory
of Data
layers
(GIS)
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
Integration of GIS and WQ/Hydrologic models
Ad-hoc (loose) integration
Operating system1
GIS
User
File Exchange
Interface
Operating system2
Process Models
User
Integration of GIS and WQ/Hydrologic models
Partial (close) integration
Operating system 1
GIS
File Exchange
Interface
User
Operating system 2
Process Models
Integration of GIS and WQ/Hydrologic models
Complete integration (modeling within GIS)
Common operating system
GIS
Pre-processor
Process
Models
Post-processor
Interactive User Interface
User
(adopted from Tim and Jolly, 1994)
Disadvantage of Complete Integration
(modeling within GIS)
The GIS software are not designed for
Water Quality/Hydrologic modeling.
Difficult to perform complex mathematical
computation processes
Longer data processing time
(computational time)
GIS Functions
• Edit
–Topology
• Build feature
• Drop feature
• Create label
• Centroid label
• Renumber node
• Coordinates
– Transform
– Project
– Define Projection
• Convert
• Map sheet
– Append
– Clip
– Map join
– Split
GIS Functions
• Analysis
– Overlay
• Identity
• Intersect
• Union
– Proximity
•
•
•
•
•
Buffer
Buffer region
Near
Point distance
Theissen
– Update
• Erase
• Update
– Extract
• Clip
• Select
– Merge
• Append
• Dissolve
• Eliminate
GIS Functions
– Conversion
• Poly to region
• Arc to region
• Union
• Geocoding
• Grid:
– data conversion
• Image
– Georectification
• TIN
• Measurements
• Cut-fill
• Volume
– Analysis
•
•
•
•
Contour
Profile
Line of site
Visibility
GIS Functions
• Tables
– Info Item
– Table summery
– External DBMS
Open Source GIS
• Free
• Secure: no supplier dependence
• Encourages involvement and sense of ownership;
internationalization
• Support network via internet
• High quality
• Good maintenance
• Open standards; interoperability
MapWindow GIS
•
MapWindow GIS
•MapWindow GIS is an open source GIS (mapping)
application and set of programmable mapping
components. Because it is distributed as an open source
application under the Mozilla Public License distribution
license, MapWindow GIS can be reprogrammed to
perform different or more specialized tasks. There are
also plug-ins available to expand compatibility and
functionality. MapWindow GIS is built upon Microsoft
.NET technology but is not a multi-platform application
and hence does not run on non-Microsoft operating
systems including Mac OS X, Linux, and UNIX.
MapWindow Innovation
D8 Algorithm
Flow in 1 of 8 preset
directions
D∞ Algorithm
Flow partitioned into up to 2
directions based on steepest
slope on each of 8 facets

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