multidimensional images raw data format

Question

Is there a lowest common denominator format for multidimensional images or matrices analogous to netpbm/netpgm for 2d images?

How would you use protocol buffers to define a 3d image or matrix of 16 bit unsigned numbers?

Why didn't the netpbm people allow more dimensions in the row, column line?

Answer 1

Wouldn't it be easiest to just have the first line declare the data structure followed by the binary data.
For ex.

char * \n
Hello World!

unsigned char [2][2][2]\n
0000000000

Answer 2

I believe FITS and NetCDF fit into that role.