NetCDF Driver should read/write data in stripes instead of the whole array

[rsignell]

When I tried to convert a 20000x15000 file using the GMT driver (which writes NetCDF with Z as a 1D variable) it works fine, but the NetCDF driver gives an "Out of memory" error:

gdal_translate psdem_2005_geo.tif -of netcdf psdem_2005.nc Input file size is 20000, 15000 0ERROR 2: CPLMalloc(): Out of memory allocating 1200000000 bytes.

It looks like the NetCDF driver is trying to allocate memory for the entire data grid being processed instead of reading/writing by column, row or chunk. This should be fixed, to allow processing of much larger grids on machines with limited memory.