ELVIS – DEM & Point Cloud Notes

map of ELVIS 5m data coverage, eastern states

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

Tips for using OCAD’s SASPlanet guide

Google satellite image

Downloading Georeferenced Satellite Images

A few notes to clarify the generally good wiki instructions.

  • 2. I find the selection of extent is better done in 3, after opening the Selection Manager tool which is the second menu symbol.
  • 3. The Selection Manager allows varied means of selection. For a rectangle, your 2nd click starts the drawing.
  • 3. Then select the Stitch tab. The settings shown work well. Do select an appropriate folder for the resultant background image.
  • 3. The image above is zoom level 20. Higher zoom levels significantly increase data volume as does selecting png rather than jpg.
  • 7. If your map coordinate system is not Google Mercator (mine was GDA94/MGA94), then you need to select Transform so as to identify Google Mercator as the coordinate system of the Image.
Input screen if SASPlant coord system varies from your map coord system

Faced with the realisation that SASPlanet is not from a source known to me and also is delivered as an executable, I was rather nervous. OCAD’s endorsement was a promising start, soon diminished somewhat in finding SASPlanet wikipedia entry is in Russian. OSM’s wiki entry is brief.
However, after a fair bit of searching I came to the conclusion that the risk is acceptable. The latest version is in BitBucket 17MB. Do please use Comments to let us know how useful it is to you.

Smoothing lidar data

To Bezier curve first

In my early days of handling lidar data I was getting unacceptable results from smoothing lidar data. A tip from OCAD Inc fixed my issues immediately.

Change the contours to Bezier curve first, then smooth.

Why? Because a better contour curve results from more vertices.