Title

Vicmap Elevation 1m Digital Elevation Model (DEM) 

Alternate title

VICMAP_ELEVATION_1m_DEM 

Purpose

Delivered as spatial web services, the Vicmap 1m DEM aims to make the best terrain surface data easily accessible and replaces the need for users to physically manage their own copy of the data. The 1m DEM includes the best datasets from the Vicmap LiDAR DEMs collection. The collection contains high accuracy and detailed ground surface model datasets designed for many and varied applications including: use as terrain surfaces in 3D and digital twin environments, flood modelling, river channel and land surface change detection, mine shaft mapping, coastal inundation modelling and general landscape and land use suitability analyses. 

Supplemental Information

Relationship to other Datasets: See Vicmap LiDAR DEMs Collection. Metadata Identifier: 29c2e719-2b05-5208-937d-ab4ce2ca3e38 Related Documents: Please see Vicmap Elevation 1m DEM product description for more detailed information on this product. This can be found on the Vicmap Elevation Webpage. https://www.land.vic.gov.au/maps-and-spatial/spatial-data/vicmap-catalogue 

Status

Completed  

Code

Geographicals on GDA2020 

Maintenance and update frequency

Irregular  

Title

Cloud Optimised GeoTIF 

Topic category

• Elevation
• Environment
• Geoscientific information

DELWP Categories

• Vicmap Products

Use limitation

Vicmap Elevation 1m DEM is subject to licensed use. A Data Access License Agreement (DALA) provides the terms and conditions of use, including license fees determined under the Vicmap Elevation Subscription Model. 

Classification

Restricted  

Statement

Dataset Source: Vicmap 1m DEM derives from LiDAR survey projects undertaken through the States Coordinated Imagery Program (CIP). LiDAR surveys are conducted on behalf of the State by commercial aerial survey companies that have qualified for the relevant State services panels. Acquisition planning is driven by purchase partner investment in the CIP program and is implemented in an on-demand basis. Aerial survey most often occurs as a single project achievable within one flying season by a single commercial supplier. As investment and funding allows, larger capture programs may occur that span multiple flying seasons and require multiple commercial suppliers to complete. LiDAR survey within Victoria is achievable throughout the whole calendar year, however most data capture has been conducted during the spring, summer, and autumn seasons (November through to May). Dataset Originality: Primary 

Description

Collection Method: Aerial LiDAR Survey 

Description

Vicmap LiDAR DEMs are constructed from LiDAR points classified as ground. The model defines a bare earth ground surface and is devoid of trees and human-made structures. In summary terms, the DEM generation approach employs a Point to TIN and TIN to Raster process with Natural Neighbour interpolation. The surface models exclude road and rail bridges as well as major culverts. If these features were incorrectly classified as LiDAR ground points and automatically included in the DEM, they are subsequently edited out of the model in a manner that ensures the underlaying terrain is continuous and not left as a gap or void in the surface. Datasets meeting 1m resolution and +/-10cm RMSE vertical accuracy standards are included in the 1m DEM mosaic. The mosaic is a "virtual mosaic" of constituent datasets layered by year of capture and then published as ESRI REST and OGC web services. 

Classification

Unclassified  

Attribute Quality

Comments

As the LiDAR DEMs represent the bare earth ground surface, the attribution of the dataset is reflected in the vertical elevation values of the dataset. In this sense, the attribute accuracy is commensurate with the vertical accuracy of the surface which ranges between +/- 10cm RMSE and +/- 50cm RMSE for different datasets in the collection. Vicmap Elevation LiDAR DEMs are most correct when used in their native datums and projections. Transforming and reprojecting DEMs may alter and reduce the fidelity of the elevation values for the transformed or reprojected coordinate. 

Positional Accuracy

Comments

Horizontal Accuracy is greater than or equal to +/- 30cm RMSE. All LiDAR surveys from which the LiDAR DEM datasets are derived are rated at +/-30cm RMSE horizontal accuracy. Greater horizontal accuracies are now achievable and have been demonstrated in the more recent LiDAR surveys that have contributed LiDAR DEM datasets. Only datasets meeting +/- 10cm RMSE vertical accuracy are used in the Vicmap 1m DEM. 

Conceptual Consistency

Comments

The LiDAR DEM datasets are all consistent in their data representation of AHD. As described, variations exist in resolution and vertical accuracy. Additionally, there will be variation in the degree to which older datasets have been hydro flattened and bridges treated, as surface modelling improvements have evolved over time. 

Missing Data

Comments

The collection covers approximately 60% of the land area of Victoria and approximately 99% of the populated areas. As an expanding collection, coverage continues to grow in temporal and spatial terms as new datasets are added. Completeness Verification: Each dataset in the collection has been verified for conformity with the vertical accuracy specifications for the LiDAR survey under which the data collected. Vertical accuracy requirements vary between projects from +/-10cm RMSE to +/-50cm RMSE. 

Excess Data

Comments

LiDAR DEM datasets used in the 1m DEM mosaic represent the bare earth surface as the only data class. Bridges do not form part of ground surface and are excluded from the DEM datasets.