Title

Victorian Coastal Nearshore Bathymetry 20m resolution DEM 5m Contours 

Alternate title

VIC_NEARSHORE_BATHY_20M_DEM_CONT 

Supplemental Information

Related Documents: None 

Status

Completed  

Horizontal Accuracy

2m  

Code

4283 

Maintenance and update frequency

Not planned  

Title

Vector, Raster 2 

Topic category

• Oceans

Use limitation

Used in a variety of applications,including environmental modelling. 

Classification

Unclassified  

Statement

Dataset Source: A. 2.5m Bathymetry collected for Future Coasts, DSE using LiDAR technology (during the period 26Nov2008 to 03APR2009) covering the majority of the nearshore off the coast of Victoria. B. 2.5m Bathymetry derived from Multi-beam Sonar, collected in June 2010 for sections of Westernport Bay. Dataset Originality: Derived 

Description

Collection Method: Source Data was collected using Airborne LiDAR 

Description

Processing of LiDAR-derived bathymetry: 1. bathy 2.5m was first resampled to 5m (processed in UTM Projection) 2. 5m bathy in UTM reprojected to VICGRID94 3. Bathy 5m was resampled using Focal Mean 4*4 rectangle, saved as 20m raster 4. Paleao-channels masked out Processing of MultiBeam-derived bathymetry: 1. source bathy 2.5m was first resampled to 5m (processed in UTM Projection) 2. 5m bathy in UTM reprojected to VICGRID94 3. Bathy 5m was resampled using Focal Mean 4*4 rectangle, saved as 20m raster Merging data 1. All data was mosaiced together using a "blending" algorithm - the output in the overlapping areas is a horizontally weighted mean. 

Classification

Unclassified  

Attribute Quality

Comments

The vertical accuracy associated with the source data is +/-26cm @ 68% confidence or better. However, reprojecting, changing format or resampling causes changes to the height values in the DEM. The vertical accuracy associated with the contours is such that 95% of "well defined" points along the contour line have a value that must not differ to the "true" ground surface by any more then half of the contour interval, in this case 1.0m. 

Positional Accuracy

Comments

The horizontal accuracy for the source datasets is +/-1.62m. 

Conceptual Consistency

Comments

The depth values across tiles of the source data have been constructed to ensure smooth consistent elevation values was achieved. Logical consistency is a measure of the degree to which data complies with the technical specification. The test procedures include a mixture of scripts and on-screen visual checks. 

Missing Data

Comments

This bathymetric dataset is only along the Victorian coast and extends to approximately the 20m depth contour. 

Excess Data