[PATCH] Northwood GRD write support
|Reported by:||jamesramm||Owned by:||warmerdam|
|Severity:||normal||Keywords:||NWT_GRD, driver, write, raster|
This patch adds write support to the Northwood GRD driver (NWT_GRD). Northwood Grid is also referred to as Vertical Mapper Grid or MapInfo Grid
The read driver creates 3 'virtual' RGB bands (i.e. they are mapped from the single data band on disk), with the 4th band being the data band. In write mode, there is therefore just 1 band. To make switching between read/write mode less clunky, I think it would be helpful if the band order in read mode was data, R, G, B rather than the current R, G, B, data. Then the actual data band would always be band 1 regardless of the mode. This would prevent things like statistics being calculated in write mode then showing up in the wrong band for read mode.
However, this would be a breaking change (albeit relatively minor), so I have not included it in the patch, but I'd like seem feedback on whether such a change could be included?
The write support is not fully complete. There is potential to:
- Allow different data types in write mode and just convert these to the on disk data type...
- Support more creation options to alter the header/tab file information. This is less desirable as this stuff (transparency, colour options etc) only has any affect when opening the file in mapinfo;
- Map the on-disk no data value to whatever was specified when writing, using the PAM dataset to store the desired no data value