Authors / CoAuthors
Abstract
AAMHatch acquired Airborne Laser Scanning (ALS) data for the Sydney Metropolitan area between 11 June 2007 & 7 July 2007 and again in February to June 2008. The source data are available as mass points (ASCII XYZ, LAS) and Gridded 2m and 10m DEM tiles or 2m Mosaic. The vertical accuracy is 0.15m at 1 sigma in open clear ground as specified in the project scope. A hydrologically conditioned and drainage enforced 2m DEM or HDEM has also been developed by SKM in both MGA Zone 56 and in GCA GDA94 projection in ESRI GRID format. Hydrologic enforcement and conditioning has included the testing of data for sinks, the referencing of transport and hydrology vector layers for intersections and flow, and the use of high-resolution imagery for visual validation. The methodology for hydrologic enforcement has required deriving a stream network based on flow direction and accumulation, using TIN and ANUDEM processes to analyse sinks and artificial damming affects caused by objects such as roads, bridges and trees which have not been previously filtered. Break lines have been included via the insertion of culvert/drainage channels, which has been used to interpolate these features into the main DEM as descending grid values. All data are referenced to GDA94/MGA Zone 56 and AHD using independent survey control which means the project area is not seamless and height difference between the 2007 and
Product Type
dataset
eCat Id
70580
Contact for the resource
Custodian
Owner
Custodian
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- DEM topographic
- ( Theme )
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- 3D model
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- AU-NSW
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Topology
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- Published_Internal
Publication Date
2010-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Special, MOU, etc.
Access - restricted
Use - license
Status
Purpose
Maintenance Information
notPlanned
Topic Category
elevation
Series Information
Lineage
Laser strikes have been classified into 'ground' and 'non-ground', based upon algorithms tailored for major terrain/vegetation combinations existing in the project area. The definition of the ground may be less accurate in isolated pockets of dissimilar terrain/vegetation combinations. Laser return: Last and first pulse. Data thinning: Points not contributing to the terrain definition within 0.04m removed Captured terrain model: 1.6m average point separation Limitations of use: The definition of the ground under trees and at the boundaries of water bodies may be less accurate. NEDF Metadata Acquisition Start Date: 11/06/2007 Acquisition End Date: 7/07/2007 Sensor: LiDAR Device Name: - Flying Height (AGL): UNK INS/IMU Used: - Number of Runs: UNK Number of Cross Runs: UNK Swath Width: UNK Flight Direction: - Swath (side) Overlap: UNK Horizontal Datum: GDA94 Vertical Datum: AHD71 - AusGeoid98 Map Projection: MGA56 Description of Aerotriangulation Process Used: - Description of Rectification Process Used: - Spatial Accuracy Horizontal: 0.75 Spatial Accuracy Vertical: 0.15 Average Point Spacing (per/sqm): 1.4 Grid Resolution: 2 Laser Return Types: Last and first pulse Data Thinning: < 0.04m removed if not contributing to terrain definition. Laser Footprint Size: 0.3 Surface Type: DEM Product Type: GRID Distribution Format: ESRI GRID Calibration certification (Manufacturer/Cert. Company): AAM Hatch Limitations of the Data: The definition of the ground may be less accurate in isolated pockets of dissimilar terrain/vegetation combinations and at boundaries of water bodies. Independent survey control was used thus the project area is not seemless and height difference between the 2007 and 2008 data will exist. Processing/Derivation Lineage: AAM Hatch WMS: http://WIN-UDEM2:8399/arcgis/services/Sydney_2007/MapServer/WMSServer?
Parent Information
Extents
[-34.02, -32.709, 150.9, 151.116]
Reference System
Spatial Resolution
Service Information
Associations
Downloads and Links
Source Information
Sydney Hydrological Enforced DEM (HDEM) 2007-2008