Arc Hydro
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Review of geodatabase issues
• Adding shapefiles and coverages into an ArcMap
session does not make a geodatabase
• Loading shapefiles and coverages into a
geodatabase does not make a (efficient)
geodatabase.
• Ignoring geodatabase capabilities increases cost of
development and ownership
• When developing data, ignore spatial reference
issues at your own peril
• SDE and versioning (including disconnected editing)
do not replace the need for careful workflow
development
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How “Things” Build Up
• Database development
• Data preparation
• Terrain preparation
• “Watershed” delineation
• “Watershed” characterization
• Parameterization
Generic
Semi-Generic
• Model pre and post-processing
Model Specific
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Arc Hydro
Template Data Model
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Template Data Models
Project Data Models
FEMA
HEC
…
GIS/IT Standards
ISO
Template Data Models
FGDC
Arc Hydro
Parcel
…
OGC
ArcGIS Core Data Model
Industry
Object
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Feature
Topology
Templates
Provide an
Important Link
Between
Project Teams,
Standards, and
ESRI Software
Development
Arc Hydro
• Extension of geodatabase model for support of water
resources applications (template data model)
• Culmination of a three year process led by D.R.
Maidment through GIS in Water Resources
Consortium (Arc Hydro book)
• Collection of tools for support of Arc Hydro
geodatabase design and basic water resources
functions
• Starting point for water resources database and
application development
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Basic idea: Transition from …
Streams
Drainage Areas
Hydrography
Channels
Terrain Surfaces
Rainfall Response
Digital Orthophotos
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Data Model
Based on
Inventory
… and …
Follow a drop of water from where it falls on the land, to
the stream, and all the way to the ocean.
Data Model
Based on
Behavior
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… to Arc Hydro Data Model
Integrate Data Inventory using a Behavioral Model
Relationships between
objects linked by tracing path
of water movement
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Basic Concepts
• Define core feature classes for water resources analyses
• Establish relationships between core feature classes
• Use geometric network for tying pieces together
• Mobilization of standard ArcGIS functionality
• Custom tools for some of the attribute management
• Custom tools for advanced “water resources”
functionality
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Data Model Purpose
• Target audience: Water resources (surface)
community interested in quick start in ArcGIS
implementation
• Starting point for project model design
• Not a “do all” design
• Not implementation/application specific, but
provides the key components to develop on top of
– The user needs to add additional data structures for their
specific requirements – still work to be done!
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Template Data Model Approaches
Water Resources
Floodplain
WQ
Arc Hydro
Permitting
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Arc Hydro Database Definition
• A geospatial and temporal data model for water resources
that operates within ArcGIS
• Five key conceptual areas
– Drainage - Drainage areas and stream lines defined from surface
topography
– Flow network - Connected sets of points and lines showing
pathways of water flow
– Hydrography - The base data from topographic maps and tabular
data inventories
– Channel description - A 3-D line representation of the shape of
river and stream channels
– Time series - Tabular attribute data describing time-varying
water properties for any hydro feature
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Arc Hydro Data Model
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Arc Hydro Data Model Details
• Detailed representation at the end of corresponding
chapters in the book (e.g. p 51)
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Arc Hydro Key Fields
• Few predefined fields/attributes
– Identification/relates
• HydroID, NextDownID, DrainID, JunctionID, FeatureID, …
• HydroCode, ReachCode, CSCode, …
– Measures
• LengthKm, AreaSqKm
• LengthDown, DrainArea
– Auxiliary
• FType, Name, Flowdir, …
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HydroID Story
• HydroID – a unique integer identifier for every
feature within a geodatabase
• An internal identifier whose value is used for
establishing the relationships within the Arc Hydro
data model (HydroID, DrainID, NextDownID,
JunctionID, …)
• Focus on local (within a geodatabase) uniqueness,
but can be made global
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HydroCode Story
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Relationships
• Establish a formal (geodatabase) relationship
between two feature (object) classes using
predefined ID properties.
– HydroID-based (e.g. NextDownID, JunctionID, DrainID)
•
•
•
•
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“HydroJunctionHasWaterbody”
“HydroJunctionHasWatershed”
“HydroJunctionHasMonitoringPoint”
“MonitoringPointHasTimeSeries”
Relationships (an example – “HydroJunctionHasWaterbody” - definition)
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Relationships (an example – “HydroJunctionHasWaterbody” - design)
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Relationships (an example – “HydroJunctionHasWaterbody” - use)
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Connecting to Time Series
Flow
DrainagePoint
HydroID
Junction
FeatureID
Time
TimeSeries
HydroPoint
CrossSection
FeatureID of time series
is HydroID of the feature
the time series describes
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Time Series Data Structure
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Time Series Dilemma
• Simplicity in structure
– Easy to import and export time series data from other sources
– Easy to use standard ArcGIS tabular functionality and SQL
statements
– Needs “transposition” for efficient rendering of spatial data
– Large table with potentially millions/billions of records
– Inefficient storage of specific types of temporal data (many to
many case)
–…
• Need more flexibility (but at a cost of complexity)
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Hydro Network
• Backbone of Arc Hydro - establishes connectivity
between core feature classes
• Hydro edges (lines through which water flows) and
junctions (confluences, other points of interest)
• Other feature classes connected to junctions through
relationships (e.g. HydroJunctionHasWatershed)
• Allows upstream/downstream tracing (and other out of
box ArcGIS network functionality)
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Hydro Network
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Extending Arc Hydro Data Model
• Arc Hydro is by design a starting point for
complex database design
• Arc Hydro data model can be extended with
additional feature classes and/or attributes (or
some Arc Hydro feature classes can be
ignored)
• Use additional GIS data sources (GRID & TIN)
• Use all existing IDs and tools to minimize
duplication of effort
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Extending Arc Hydro Data Model
More application
specific “stuff”
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Arc Hydro Tools Key
Concepts
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Arc Hydro Tools Faces
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Key Concepts
• Transitions between the raster and vector worlds –
integrated operations
• “Relationships between objects linked by tracing
path of water movement”
Raster
Extended Network
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Vector
Network
Logical Schema
Arc Hydro Tools Overview
(1)
• A set of tools that “exercises” the Arc Hydro model
– Integral with standard ArcGIS functionality
• Key field (property) management.
– HydroID & related IDs
– Length/Area measures
• Core functions
– DEM-based watershed delineation
– Network generation
– Attribute and network tracing and summary operations
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Arc Hydro Tools Overview
(2)
• Distribution (version 1.1)
– A toolbar with packaged menus and buttons
– Supporting documentation/help
– ArcGIS 8.3 and ArcGIS 9/9.1 versions
• ApFramework
– Simplify boring development tasks
– Consistent development structure
– Starting point for additional functionality development
• ApUtilities
– Set of utilities common to most ArcObject-based
applications developed at ESRI Professional Services in
water resources area
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Arc Hydro Tools Overview
• The Arc Hydro Toolbar
– Terrain Preprocessing
– Terrain Morphology
– Watershed Processing
– Attribute Tools
– Network Tools
– ApUtilities
– Buttons
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(3)
Arc Hydro Tools Overview
(4)
• Terrain Preprocessing
– Set of functions for processing of DEMs
– Preprocessing of DEM-based data needed
for watershed delineation and watershed
characteristics extractions
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Arc Hydro Tools Overview
(5)
• Terrain Morphology
– Set of functions for:
• Characterization of drainage areas (E-A-V)
• Characterization of drainage boundaries (E-A-W)
• Area connectivity (“spider web”)
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Arc Hydro Tools Overview
(6)
• Watershed
Processing
– Set of tools for
watershed
delineation and
characteristics
extraction
– Every menu has a Data
Management form for setting up
the layers to be used in operations
associated with that menu (not
required as each tool will request
input and output data if necessary).
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Arc Hydro Tools Overview
• Attribute Tools
– Set of tools for attribute
management (some of the
tools require geometric
network)
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(7)
Arc Hydro Tools Overview
• Network Tools
– Network specific tools
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(8)
Arc Hydro Tools Overview
(9)
• ApUtilities
– Various utilities common to multiple
applications
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Arc Hydro Tools Overview
• Buttons
– Flowpath tracing
– Point delineation
– Batch point generation
– Assign related identifier
– Global point delineation
– Trace by NextDownID
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(10)
HydroID – Cornerstone of Arc Hydro Tools
• Together with relationships, key element in operation
of tools !
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Walk-through
• Local delineation
• Characterization
• Trace on the network using standard network tracing
techniques
• Trace using NextDownID
• Accumulate
• Schematization
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Many Aspects of Arc Hydro
Database design
Marketing
Tools
Application
“Standard”
Development environment
Saxe, John Godfrey, 1963, “The Blind Man and the
elephant”, New York: Whittlesley House
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Elephant illustration ©2002 Jason Hunt
www.naturalchild.org/jason
Where’s Arc Hydro?
• Hydro model page at:
support.esri.com/datamodels
• Arc Hydro home page at GIS Water Resources
Consortium at: www.crwr.utexas.edu/giswr/hydro
• Dr.Maidment’s home page at:
www.ce.utexas.edu/prof/maidment
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FTP Download Site
• ftp:
ftp.esri.com
• username: RiverHydraulics
• password:
river.1114
• directory:
ArcHydro
• Case sensitive
• Make sure you log in (most browsers will log you
in as anonymous and you will not be able to
download)
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