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Hydrologic Cycle: Connecting the Land Surface with the Atmosphere

Connecting Hydrology and Meteorology

Regional flood analysis in Houston

Nexrad Rainfall for Storm of Oct 1994

Discharge in Buffalo Bayou at Katy October, 1994 storm

Calibrated Flow with HEC-HMS

Global Runoff (mm/yr)

GTOPO30 - 30 Digital Elevation Model of the Earth

Drainage in North America

Drainage Basins of North America

Streamflow Hydrographs for Large Basins

A Fundamental Dilemma

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Geospatial Database: a set of compatible data layers or themes

Spatial Data: Vector format

Feature Attribute Table

Relational Linkages

Locations on the Stream Network

Watersheds defined using a Digital Elevation Model

Spatial Data: Raster format

Points as Cells

Line as a Sequence of Cells

Polygon as a Zone of Cells

Raster-Vector Data Model

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Study Region in West Austin

Watershed Delineation by Hand Digitizing

30 Meter Mesh Standard for 1:24,000 Scale Maps

DEM Elevations

DEM Elevations

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Austin West 30 Meter DEM Elevations in meters

Flow Direction Grid

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Stream Network for 5 cell Threshold Drainage Area

Streams with 200 cell Threshold (ᡊ hectares or 13.5 acres drainage area)

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Watershed and Drainage Paths Delineated from 30m DEM

DEM Data Sources

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Shape of the Earth

Geographic Coordinates (f, l, z)


Ellipsoid or Spheroid Rotate an ellipse around an axis

Representations of the Earth

Definition of Elevation

Coordinate System

Earth to Globe to Map

Conic Projections (Albers Equal Area, Lambert Conformal Conic)

Cylindrical Projections (Universal Transverse Mercator)

Azimuthal (Lambert Azimuthal Equal Area)

Presentation Summary

Author: maidment


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Other information:
AMS Meeting, Dallas, Jan 1999

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