Create a geometry
Da MeteOceanWiki.
In order to create a geometry it is possible to use a software called "BlueKenue". You can download the software from the following link (after filling in a form):
http://www.nrc-cnrc.gc.ca/eng/solutions/advisory/blue_kenue/download_blue_kenue.html
A very useful tutorial to build a geometry can be found here:
Note that the file you download is in .7z format.
If you are not interested in GIS applications you can start to read directly from chapter 3.