Automated H&H and Advanced Terrain Processing

Austin – Charlotte - Cary - Greensboro

Symposium on Terrain Analysis For Water Resources ApplicationsAustin, TX December 16th – 18th , 2002Joseph B. Chapman, PE, CFMSenior Vice-PresidentGray Minton, PE (not in TX)Senior Software Engineer

Overview of Presentation

• Issues Related to Terrain Management• Overview of WISE• Terrain Processing Techniques• Automated Hydrology Functions• Automated Hydraulics Functions• Automated Floodplain Mapping

Terrain Data and ManagementManagement of Terrain is Key to any Automated

H&H Process

WHAT IS LIDAR?

• LIDAR = LIght Detection and Ranging• 20-25 cm RMSE Accuracy

Multiple LIDAR ReturnsTrees (canopy)Bare Earth

IF YOU DON’T KNOW THIS YOU MUST HAVE BEEN ASLEEP FOR 2 DAYS!

How Much Data is LIDAR Data?

LIDAR Points

How Much Data is LIDAR Data?One (1) Project Tile:•20k x 20k (14 Square Miles)•950,000 Mass Points•215 MB Shape File

How Much Data is LIDAR Data?

1,228 Tiles in Phase I !!(4 Eastern Watersheds)

Here’s Where We Store It!

What is WISE?• Tool for managing and utilizing data for watershed studies• Provides integration of GIS and standard engineering calculation

programs• Modules for:

– Terrain Storage– Inventory Management– Hydrologic Analysis– Closed System Analysis– Open Channel Analysis– Water Quality Analysis– Master Planning

WISE is Based on?

• Written in Visual Basic with a few DLL’s in C.

• Based on ESRI’s MapObjects

• Interfaces with Standard Calculation Engines

• WISE IS NOT A MODEL

WISE Terrain Module

The Terrain module in WISE is an integrated suite of tools that:

• Imports terrain data in numerous different formats• Stores and provides quick access to very large

amounts of data• Combines terrain data based on user-assigned

priorities• Generates TIN’s and DEM’s• Hydrologically corrects the terrain data• Provides the foundation for tools in other modules such

as basin delineation and cross section takeoff

WISE Terrain Import

• WISE allows the user to import terrain data in numerous formats, including:– LIDAR data– AutoCAD DXF’s– Numerous ASCII formats

• WISE stores all of this data in a unique storage system with unlimited storage capacity.

WISE currently stores complete TIN for 15,000 Square miles and growing!

(4 + billion points)

Blending of Terrain DataWISE allows the user to combine multiple different types of terrain data based on user-defined priorities

TIN and DEM Generation

• WISE creates TIN’s from the blended terrain data

• WISE also creates DEM’s, which are later used during the hydrological correction process. These DEM’s can be exported for use in other programs such as ArcView.

• Once new Terrain data becomes available, TIN’s can be regenerated for an area without having to recreate the whole model

Hydrological Correction• Typically the most time-consuming part of the project• WISE speeds up this process dramatically by

automatically fixing sinks, peaks, and flat areas using its own program, FAUCET

• Advantages of FAUCET– Allow for use of unlimited size data sets by tiling data– Handles negative values– Extra precision has been added (not critical for NED Data)– Doesn’t Fill Sinks! – This is important in preserving

integrity of as much of the data as possible

Example FAUCET Correction

Tools that use the Terrain Output

• Hydrology: Raindrop Tool, Drainage Area Tracking, Basin Delineation, Time of Concentration Calculation

• Hydraulics: Cross Section Placement, Cross Section Takeoff

• Water Quality: Spill Response Modeling

Compatibility/Usability of Results

• Manage TIN in WISE – export to any program that accepts dxf or shapefile

• Generate a hydrologically correct DEM that can be used by any program that can except standard data formats

• Standard GIS and CADD programs do not have to store the data

Automated Hydrology Tools

WISE has numerous tools that help a user manage and create hydrologic data including:• Automatic Basin Delineation• Automatic Time of Concentration Calculation• Curve Number Calculation• HEC-1/TR-20 model creation

Basin DelineationWISE will allow a user to automatically delineate

basins based on a target basin size

Time of Concentration Calculation• WISE will automatically determine the longest TC for a basin

based on longest flow length or longest flow time• WISE currently allows the user to calculate TC’s based on 5

different methods, including SCS TR-55• WISE also determines Routing Time of Concentration flowpaths,

and calculates the stage/storage curves for each routing

Curve Number CalculationWISE will calculate Curve Numbers for a given set of basins

Hydrologic Model CreationWISE will automatically create a complete hydrologic model for a given area

Metadata Already Created Tracking How Model was

Created!

Automated Hydraulic Tools

WISE has numerous tools that help a user manage and create hydraulic data including:• Automatic Cross Section Placement• Cross Section and n-value takeoff• HEC-RAS model creation• Floodplain mapping• Flood profile creation

Automatic Cross Section Placement

Manual Cross Section Edits

Survey Data Import

Feature Code Library

Standard Code Library has been used for thousands of structure surveys

HEC-RAS Model Creation

Floodplain Mapping

Efficient Management of Terrain Data Make All These Other

Processes Possible

• Hydrology: Raindrop Tool, Drainage Area Tracking, Basin Delineation, Time of Concentration Calculation

• Hydraulics: Cross Section Placement, Cross Section Takeoff

• Water Quality: Spill Response Modeling

QUESTIONS?

Austin – Charlotte - Cary - Greensboro

www.watershedconcepts.comwww.ncfloodmaps.com