[gdal-dev] Virtual Raster Tile Index (VRTTI) driver, and associated gdaltindex improvements

[Even Rouault]

Andrew,

Le 21/12/2023 à 13:55, Andrew C Aitchison via gdal-dev a écrit :
> On Wed, 20 Dec 2023, Even Rouault via gdal-dev wrote:
>
>> Hi,
>>
>> For those not actively following github tickets & PR, I just want to 
>> point to a new pending major functionality to improve management of 
>> virtual mosaics with a very large number of tiles/sources (> tens of 
>> thousands of tiles), by referencing them as features of a vector 
>> layer (typically created by gdaltindex), instead of a XML file as in 
>> traditional VRT, augmented with additional metadata.
>>
>> More details in https://github.com/OSGeo/gdal/pull/8983 (and in 
>> initial ticket in https://github.com/OSGeo/gdal/issues/8861)
>
> Am I right in thinking that all the tiles must have the same
> bit-depth and colour interpretation

Yes. If different bit-depth and rescaling is wished, you'll have to 
manually use for example 
"vrt://the.tif?scale=src_min,src_max,dst_min,dst_max" as the source 
name. Cf https://gdal.org/drivers/raster/vrt.html#vrt-connection-string

If bands are ordered differently, similarly use things like 
"vrt://the.tif?bands=3,2,1" to reorder them in a uniform way.

> and for paletted tiles
> the same colour table ?

I've just added support for automatically expanding color tables to 
RGB(A) if the BAND_COUNT metadata item is set to 3 or 4.

Even

-- 
http://www.spatialys.com
My software is free, but my time generally not.