Refactor openwind and make it compatible with Python 3 and Nansat v1.1

[mortenwh]

Challenges:

• we operate on potentially three Nansat objects:
  1. A model wind field, e.g., NCEP
  2. A SAR NRCS image
  3. A SAR Doppler image
• optionally, two Nansat objects plus a constant (or a numpy array of) wind direction(s)
• In addition to this, we should consider adding other data as well, e.g., from scatterometers..
  • OpenWind only makes calculations
  • OpenWind class takes only arrays as input
  • OpenWind class needs to be able to apply an unlimited amount of wind datasets/arrays
  • Generate new Nansat object after processing
  • Writes to file
• Importer class (does not need to inherit from Nansat but needs to handle domains)
  • from_nansat (uses Nansat, including reprojection handling(?))
  • from_float
  • from_string
  • etc.
• Exporter class
  • e.g., to store only wind field

TODO's:

• [x] Add vagrantfile to openwind repos(?)

• [ ] Define the user interface: initialization with NRCS image file or initialization with all datasets (as presently)?

• [ ] Create a new core class (OpenWind) to which we connect Nansat, various algorithms and the user interface (SARWind)

• [ ] Add notes and comments in SARWind to follow up with a discussion of todo's

• [ ] Refactor SARWind

• [ ] Create unit tests

• [x] check how this todo list works

[mortenwh]

obs - we have both created branches for this issue....

[korvinos]

Yes, which one will we use?

[mortenwh]

We can use yours. Can you merge with mine and delete my branch?

[korvinos]

Yes, sure

[korvinos]

@mortenwh Done