ELVIS delivers 1m, 5m, 25m contours – free!
ELVIS is Geoscience Australia’s new elevation information system. It is free, licenced under Creative Commons and makes public LiDAR data very accessible. Thank you to Russell Rigby, mapping convenor ONSW who made me aware of ELVIS. The LiDAR data available is;
- SRTM-derived 1 Second Digital Elevation Models Version 1.0
- DEM SRTM 1 Second Hydrologically Enforced
- 5 metre Digital Elevation Model (DEM) – this delivers 1m, 5m, 25m contours
I downloaded 5m DEM data covering part of the 2015 Anglesea mtbo map, imported contours into OCAD and overlaid those on the OCAD map file of 5m contours. The correspondence was very close which is a tribute to mapper John Sutcliffe as much as to the ELVIS data.
The 5m resolution coverage, which provides down to 1m contours, is fairly thin. These surveys cover Australia’s populated coastal zone; floodplain surveys within the Murray Darling Basin, and some parts of major and minor population centres.
Maybe we will see more sand dune coastal area maps akin to those near Hobart, Auckland, Levin and Invercargill. And perhaps street and park-O where more detailed contours are desired.
Ease of use
The website isn’t yet the friendliest until you get to know it and then it does work well. Here are tips based on my learning;
- Selecting a right arrowhead symbol provides a synopsis of that data type.
- Selecting a download arrow symbol takes you to the selection of data coverage for your project.
- Selecting the globe symbol, (red when selected) shows on the map at left, the available coverage for that data.
- Selecting the ‘eye’ symbol (orange when selected) show the extent of that data coverage.
- Note the latter two symbols act like check boxes, not radio buttons.
- At time of writing, selecting the name of any state 5m dataset gives you identical national information. It also has links at right (when selected) to state mosaic downloads – these are of no relevance to OCAD use.
- Selecting the download icon frames the 5 metre DEM coverage area for that state.
Download of data
Whichever dataset you choose, the method of selecting data is the same. The download wizard is easy to follow.
- For Output Format, select Esri ASCII Grid for OCAD import. The file will be a .asc type file.
- For Coordinate system, select GDA94 for OCAD import.
The easiest method is to use the DEM import wizard available in OCAD 12 (OCAD 10 & 11 users, see the video tutorials link below); http://ocad.com/wiki/ocad12/en/index.php?title=DEM_Import_Wizard. The defaults provided in the wizard are adequate for a first run.
You can select 1m, 5m and 25m Contour Lines and produce background maps of any or all of Slope Gradient, Hill Shading, Hypsometric Map.
There are 4 video tutorials on DEM at http://ocad.com/en/support/learn-video. These videos are useful for OCAD 10, 11 and 12 users.
I created a 4 minute video tutorial on the basics of using ELVIS. View it online at www.screencast.com/t/y3MTbMzzO
And here is a base OCAD file I created to import the DEM data and then in turn it is imported into your OCAD map file with minimal symbology and colours.
Russell Rigby detected an issue that is mainly evident in steeper areas. The contours have a degree of blockiness or striations. Russell has made Geoscience Australia aware of this issue.
This is strongly evident in the steep Wilson’s Promontory contours at right.
It is less evident but still distinguishable as a series of ‘steps’ in the less steep Preston contours below right.
In many orienteering areas, the issue won’t be much of a problem. For example in the Anglesea contours, I had to inspect closely to detect the striations.
Russell Rigby and myself have made contact with ELVIS re suggested improvements and data quality concerns. We each received responses that indicate a will to continue product improvement.
Russell Rigby, ONSW mapping convenor for his experiences of ELVIS.
Geosciences Australia for releasing an easily accessible pool of LiDAR data.
NASA for the Creative Commons licenced image of 1998 storm Elvis over USA and Atlantic.