Brisbane Hydrologic Enforced DEM(HDEM) 2009  

Authors / CoAuthors

Abstract

The Brisbane hydrologically enforced digital elevation model (DEM) was created from a combination of the following surveys; Brisbane 2009 LiDAR, Redland 2009 LiDAR, Gold Coast 2009 LiDAR, Moreton Bay 2009 LiDAR and Logan 2009 LiDAR survey areas. The data is licensed for use by all Commonwealth, State and Local Government. Data acquisition and post-processing for all of the input surveys has been controlled to achieve a fundamental vertical accuracy of <0.15m (RMS, 68% CI) and horizontal accuracy within 0.45 m. Horizontal coordinates are based upon Map Grid of Australia (MGA) Zone 56 projection. Vertical coordinates are referenced to Australian Height Datum (AHD). The hydrologically conditioned and drainage enforced 2m DEM or HDEM was developed in 2010 as part of the Urban DEM project managed by the CRC for Spatial Information and Geoscience Australia. The HDEM was produced by SKM using the ANUDEM program. The HDEM ensures that primary stream/channel flow, and water flow across the land surface are accurately represented. The hydrologically enforced elevation model should be used for hydrological modelling.

Product Type

dataset

eCat Id

70691

Contact for the resource

Keywords

• DEM topographic

( Theme )

• DEM

• AU-QLD

Australian and New Zealand Standard Research Classification (ANZSRC)

• Topology

• Published_Internal

Publication Date

2009-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Special, MOU, etc.

Access - restricted

Use - license

Status

Purpose

Maintenance Information

notPlanned

Topic Category

elevation

Series Information

Lineage

Acquisition: Airborne Laser Scanning (ALS) data was acquired for the SEQ Priority Area from a fixed wing aircraft during twenty six flights between March 25th and June 09th,2009. Acquisition over tidal areas was undertaken within +/- 2 hours of low tide. Delays in acquiring the data were caused by prolonged periods of rain over the project area during March to April, 2009. Ground Support: GPS base station support was provided by SunPOZ GNSS receiver network without incident. Ground check points acquired by AAMHatch allowed an assessment of the accuracy of the ALS data and final adjustment to AHD. Data Processing: Reduction of the ALS data proceeded without any significant problems. Laser strikes were classified into ground and non-ground points using a single algorithm across the project area. Manual checking and editing of the data classification further improved the quality of the terrain model. Further Processing: Contours: Contours have been generated automatically from a smoothed triangulated ground model and visually checked for completeness and logical consistency. Some cartographic license has been applied in areas where laser points were not captured. Gaps in the ground point data from which the contours are derived exist at locations within the Gold Coast area and at Burpengary. Data for these areas were re-captured and supplied in a subsequent volume. Products: The point density of the acquired data (>2pts/sqm) places limitations on the size of tiles into which the data can be divided and subsequently managed. The data in this volume is delivered in 1 km tiles to maintain manageable file sizes and point counts. Additional products: HDEM Generation: A hydrologically conditioned and drainage enforced 2m DEM or HDEM has also been developed in 2010 as part of the Urban DEM project managed by the CRC for Spatial Information and Geoscience Australia. The HDEM was produced by SKM using the ANUDEM program. The HDEM ensures that primary stream/channel flow, and water flow across the land surface are accurately represented. The hydrologically enforced HDEM depicts water bodies as being flat, and water courses depict consistent downward flow of water unimpeded by vegetation or man-made structures such as bridges and major culverts. Drainage enforcement was limited to watercourse lines depicted on 1:25,000 topographic mapping and to the intersection of the water course layer and transport layer. Inundation Contours: For the purposes of inundation modelling inundation contours have been developed using the HDEM. The inundation extents were extracted at 0.2m intervals below 2m AHD and 1m intervals up to 10m. The inundation contours are available as polylines. NEDF Metadata Acquisition Start Date: 25/03/2009 Acquisition End Date: 9/06/2009 Sensor: LiDAR Device Name: Leica ALS50-II (S/N: 091) Flying Height (AGL): 1700 INS/IMU Used: Honeywell URIS (S/N: 56016277) Number of Runs: UNK Number of Cross Runs: UNK Swath Width: 850 Flight Direction: - Swath (side) Overlap: 25 Horizontal Datum: GDA94 Vertical Datum: AHD71 - using local Geoid model Map Projection: MGA56 Description of Aerotriangulation Process Used: - Description of Rectification Process Used: - Spatial Accuracy Horizontal: 31 Spatial Accuracy Vertical: 0.15 Average Point Spacing (per/sqm): 2.5 Grid Resolution: 1 Laser Return Types: 4 pulses (1st 2nd 3rd 4th and intensity) Data Thinning: Ground, Non Ground & Building Laser Footprint Size: 0.34 Surface Type: HDEM Product Type: GRID Distribution Format: ESRI GRID Calibration certification (Manufacturer/Cert. Company): AAM Hatch Limitations of the Data: The definition of the ground under trees may be less accurate. Building classification is derived from automatic classification only.

Parent Information

Extents

[-27.722591, -27.158571, 152.959501, 153.416256]

Reference System

GDA94 / MGA zone 56 (EPSG:28356)

Spatial Resolution

Service Information

Associations

Downloads and Links

Source Information

Brisbane_Hydrologic HDEM 2009