GOOGLE EARTH
Turn Google earth selection into a CAD mesh file.
Method using SketchUp Pro: CREATE TOPOSURFACE FROM SKETCHUP
MELBOURNE UNIVERSITY LINKS
http://www.lib.unimelb.edu.au/collections/maps/digital/digital-maps.html
NASA !! it can be hard to find the right file to download - more testing required !!
How to get satellite data from Nasa Reverb Echo site and turn into a points file.
First download and install free program called QGIS:
https://www.qgis.org/en/site/forusers/download.html
Go to http://reverb.echo.nasa.gov/
Find your site: Get the latitude and longitude from Google Maps (right click over map and select What's here?), and search in Reverb by Point.
Put a bounding box around your site.
Type "Terrain" in the search terms box.
In the Select Dataset section tick one of the datasets. Look for .hgt files.
Hit Search for Granules button at bottom. (If none are found use browser Back to try a different file).
Select file and Add to Shopping Cart.
Download.
A text file will be downloaded. Open this file and copy the URL it contains. Paste that into your browser and the actual file will download.
Open QGIS.
Layer > Add Layer > Add Raster Layer
Video on importing into Autodesk Infrastructure (similar workflow):