[gdal-dev] Rasterlite and external overviews

[Jukka Rahkonen]

Hi,

Unfortunately the nearest neighbour sampling of internal overviews of 
Rasterlite tables yields pretty poor quality and no other sampling methods 
are supported.
While trying external overviews I found two troubles. First one is that 
it isimpossible to build external overviews if there has been internal 
overviews in the table. Removing them with "gdaladdo -clean" does not 
help, the message is still:
ERROR 6: Cannot add external overviews to a dataset with internal overviews
Overview building failed.
Another problem is not big. Gdaladdo just gives a faulty error message 
first but it still creates external overviews. This is what gets printed
on the screen:

gdaladdo -ro RASTERLITE:addotest3.sqlite,table=t8000 2 4 8
ERROR 4: `addotest3.sqlite_t8000' does not exist in the file system,
and is not recognised as a supported dataset name.

0...10...20...30...40...50...60...70...80...90...100 - done.

It would be really good to have at least average method also for 
internal overviews.

-Jukka Rahkonen-