ELVIS – DEM & Point Cloud Notes

map of ELVIS 5m data coverage, eastern states
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ELVIS import note

There may be two file types on offer to you in ELVIS – DEM and Point Cloud. You can select either. If you leave the selections unticked, you will be presented with both if available.

Mark Roberts’ guide

Importing Point Cloud LAS files from ELVIS.

Ken Dowling’s guide

My blog entries re ELVIS.

My import guide in my blog relates to import of DEM ESRI Ascii Grid format. In some areas you might not get a choice between ASC and LAS.

OCAD Inc help wiki

OCAD DEM wizard import
OCAD Point Cloud Manager

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ELVIS LiDAR data mapped via OCAD

ELVIS LiDAR and OCAD

The ELVIS output format Esri Ascii Grid, can be imported directly into OCAD 12 via the Import Wizard in the DEM menu. So you not only have an easy way of obtaining the data, you also have an easy way of using it. (See my earlier post ELVIS rocks with LiDAR contours on the basics of using ELVIS).

ELVIS LiDAR vs state geospatial vector contours

For a small area of Anglesea used in 2015 for a mountain bike orienteering event, I downloaded ELVIS LiDAR and VicMap vector contours. Then overlaid them in OCAD.

The brown contours are VicMap 10m obtained via download of vector form via Shape file.  25m index contours were also obtained but do not appear in this fragment.

The other 3 colours are from ELVIS LiDAR data;

  • grey is 1m (shown only in second image)
  • green is 5m
  • purple is 25m index contour

At first glance there is a general consistency if we ignore the many minor indentations in the LiDAR lines that could be easily smoothed in OCAD.

LiDAR 5m VicMap overlay

However the 1m LiDAR does indicate the existence of two lower parts of gullies that are shown in the VicMap contours, albeit the eastern displaced. So maybe 1m contours could usefully inform the mapper at draft stage in some map areas.ELVIS LiDAR vs VicMap vector

LiDAR contours smoothed via Karttapullauten

Karttapullauten generates orienteering training maps from LiDAR data.

This is similar to the result when smoothing in OCAD except that Karttapullauten has interpolated 2.5m contours (the dashed lines). Interestingly, this makes the progression of the above mentioned eastern gully much easier to observe.

LiDAR data smoothed in Karttapullauten

Using ELVIS DEM data in OCAD

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

Following on from that is a  4 minute video showing the import of ELVIS DEM into OCAD via the DEM import wizard. (This is applicable for any DEM data). View it online at www.screencast.com/t/qBqaZrmu

Users of OCAD 10 and 11 don’t have the wizard but should be able to interpret the wizard settings.

And here is an OCAD template 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.

TIPS

  1. When you download ELVIS data, it is the .asc file that OCAD DEM import wants,not the Shape file.
  2. If you get nothing showing after import, then check the .asc file content. You can use any text editor to read it. In the header lines there is a value for NODATA. If the file is composed completely of that value then there is no LiDAR data for the area you selected. ELVIS now warns you if there is no data in the selected area.
  3. When you are asked which co-ordinate set you wish to use, unless you have set up your OCAD file to match the location of the imported DEM data, then select the upper set which is that of the DEM data. Else the DEM data will likely be located far beyond the reach of your OCAD map area.
  4. If you expect to frequently use LiDAR data, then importing into a special OCAD file can be a boon, It should be empty and have just essential symbols that don’t clash with standard symbols for when you import that OCAD file into your working file. Such a template is downloadable from the section immediately above.
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ELVIS rocks with LiDAR contours

image Elvis storm 1998

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 Coverage

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;

Symbols of available datasets1m Hydrologically enforced DEM

  • 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.

map of ELVIS 5m data coverage, eastern states
ELVIS 5m data coverage, eastern states

 Selecting a 5m dataset5m DEM for Victoria

  • 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.

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.

Tutorials

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.

ELVIS issues

ELVIS striation issue Wilsons Prom
ELVIS striation Wilsons Prom

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.

 

ELVIS improvements

ELVIS striation issue Preston
ELVIS striation Preston

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.

Credits

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.

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New OCAD Lidar Features Example

Cornish Hill lidar vegetation height image

ELVIS lidar data processed through OCAD 2018 DEM import

Mark Roberts recently reported

Just a note that I recently downloaded some lidar data from ELVIS and imported to OCAD 2018 and the results are spectacularly good. The vegetation height function depicts clearings and buildings perfectly:

OCAD 2018 import from ELVIS Lidar image
Mark’s OCAD 2018 import from ELVIS Lidar

Mark later remarked that lidar is becoming very readily available and the OCAD processing of lidar is so easy.

VIC lidar data processed through OCAD 2018 DEM import

Following Mark’s report I received ordered lidar data for a permanent orienteering course in Daylesford, VIC. Here in VIC we do not yet have free access, however on behalf of Orienteering Victoria I have established a protocol with DELWP for access to lidar data. As their paid orders take priority it takes some weeks to fulfill an order but the wait is certainly worthwhile.

I processed the ‘irregular points’ las files through OCAD 2018 DEM import wizard, selecting all options. This provided seven background images such as hill shading, slope gradient and hypsometric shading.

Continue reading New OCAD Lidar Features Example

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Auto Generated Orienteering Maps for WOC 2016

Topo socks

Really? Auto generated orienteering maps?

Well yes and no. Read all about it on the WOC Sweden 2016 website. If you haven’t seen such maps before you will be surprised if not amazed. Continue reading Auto Generated Orienteering Maps for WOC 2016