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Output cube in details

The gridding engine can write the resulting cube in either Position-Position-Velocity order (hereafter LMV) or Velocity-Position-Position (hereafter VLM). The default is LMV. The table [*] describes both possibilities.


Table: Advantages (+) and disadvantages (-) of LMV and VLM-ordered Class cubes
Table: Advantages (+) and disadvantages (-) of LMV and VLM-ordered Class cubes
# Position-Position-Velocity (LMV) Velocity-Position-Position (VLM)
9 - need transposing the convolved data before writing to the file + correctly ordered, convolved data can be written as is
10 + the cube can easily be extended by block of velocities, in particular it may not fit in memory - the cube can not (reasonably) be extended on disk. If it fits in memory, it can be written in a temporary output buffer, with more memory cost.
11 + default ordering in Gildas, efficient for the imaging tools (one image plane is contiguous in the file) - not the default in Gildas, many tools do not expect such order
12 - need transposing for an efficient per spectrum analysis + the order is correct for spectrum-oriented tools like Class or Cube.



next up previous contents
Next: Implementation Up: Gridding with XY_MAP Previous: Gridding engine   Contents
Gildas manager 2023-06-01