Replacement raster format

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Revision as of 00:13, 3 June 2006 by HamishBowman (talk | contribs)

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 GRASS's long-standing raster format is overdue for a major overhaul.
Below you will find some ideas and roadmaps for future work.
The idea of this page is to collect ideas and flesh out a specification so that when the change occurs, all the components will be in place, pitfalls expected, and the implimentation, when it comes, quick and painless. Most importanly it can serve to keep interested parties informed and working together instead of in parallel forks.
Any changes to the data format will necessitate a bump in major version number (i.e. from GRASS 6 to GRASS 7) so if possible changes should happen in the same development cycle, and relatively minor changes should be held back in experimental status until a major change is committed.

Core raster format

Lead developer: Glynn Clements

  • Storage in tiles instead of by row.
  • Merge NULL file into main data array.

Directory structure

  • Centralize map components in "$MAPSET/raster/$MAPNAME/*" instead of many "$MAPSET/cell/$MAPNAME",etc. directories.

    Many library functions and modules will need to be updated.
    The GRASS 6 vector format has already been ported to this structure.

Meta-data support

The existing raster meta-data handling is rather weak. (currently stored in $MAPSET/hist/$MAPNAME) Total replacement will be the best option.

Brad Douglas suggests:

 It would be very advantageous to at least support metadata as specified in
 XML is an ideal file format.