Cropping curvilinear grids

[DamienIrving]

Ocean data often comes on a curvilinear grid (i.e. the latitude and longitude axes are two dimensional). The current Crop module implements xml_to_nc.py, which uses CDAT (and the cdms2 library in particular) to crop the latitudinal and longitudinal dimensions. 'cdms2' can't handle cropping of two dimensional lat/lon axes, so if people would like to be able to crop ocean data on its native grid (i.e. rather than regridding first to convert the lat and lon axes to one dimensional) then someone will need to write a module to implement the cdo sellonlatbox function, which can handle curvilinear grids.

[captainceramic]

I agree - a more modular approach with this could be a good way to go. As the xml_to_nc.py performs a couple of different functions (checking bounds, cropping, converting from xml to nc), it is probably better to have a 'sanity checker', a cropper and a xml converter as separate scripts, even if they end up being wrapped in a single VisTrails module. That would deal with this nicely.