The High Resolution Digital Elevation Model product is changing.
The National Elevation Data Strategy team carried out an analysis of the High Resolution Digital Elevation Model (HRDEM) product to improve its usability while optimizing its maintenance. The following updates will take effect on June 19th, 2024:
- Reduced duplication of UTM projections by project
- Elimination of Color Relief Map and Color Shaded Relief Map
Reduced duplication of UTM projections by project
HRDEM datasets are generated in a metric coordinate system. When produced from Lidar point clouds data, HRDEM datasets use a UTM projection.
In the current version, HRDEM projects are offered in one or more UTM zones, depending on their location.
To establish in which UTM zones the HRDEM datasets are to be produced, we use the 6-degree UTM boundaries, extended by 1 degree to the east and west. We overlay these extended zones with the project boundary to establish the list of HRDEM datasets to be produced. This approach offers greater flexibility to our users, who can choose to work in either of the UTM zones, depending on the location of their area of interest.
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Figure 1: Map showing the current datasets for a project overlapping 2 UTM zones.
This approach is much more resource-intensive and offers few additional benefits. Modern GIS software supports on-the-fly reprojections, making it easy to integrate datasets referenced to different projections. In addition, the large number of datasets visible in the product index complicates the search process.
Starting June 19th, 2024, there will be no longer be 1-degree UTM zone extensions and the HRDEM datasets will only be produced in the UTM zone(s) that overlap. The following map illustrates the final schema of HRDEM datasets for a given project.
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Figure 2: Map showing the datasets offered as of June 19th.
Elimination of derived data products Color relief map and Color shaded relief map
Our team has carried out an analysis of the derived products currently available for the HRDEM product in the form of downloadable files. To optimize our computing resources, we will be eliminating the Color Relief Map and Color Shaded Relief Map products as of June 19th, 2024. These products will continue to be available as a Web Map Service via the HRDEM Mosaic product. We therefore invite users interested in these products to use the service.
Reach out to us!
To share your comments or concerns, contact geoinfo@nrcan-rncan.gc.ca.
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