[gdal-dev] New driver implementation with larger block size

[Javier Calzado]

Hi guys,

First of all, congratulations for such a wonderful and useful library. My 
team and I are modernising a huge software legacy tool with an important 
GIS background. We decided to go with GDAL some time ago and we would like 
to get the most out of it. 

I have just finished implementing a new driver for a propietary raster 
format we have been using for years. We plan to release it as open source 
and contribute with the code when it is finished. As a first approach, 
it's been done inheriting from a RawDataset and creating a RawRasterBand. 
However, Raw driver is designed with fixed scanlines as block size. After 
some benchmarking with Google Tests framework, although performance has 
increased a bit, is not as significant as I expected compared to our old 
legacy code. Since our tool is GIS intensive, I would like to push 
performance forward. 

The main concern when comparing GDAL vs our legacy GIS code is the block 
size, we were caching much larger blocks than just a scanline. Is there 
any design reason why RawRasterBand cannot be customized with any desired 
block size? Is there any example of a larger block size driver? Any tips 
performance-wise on how to implement a driver using a different block size 
than a scanline?

Thank you for your help.
Regards,
Javier.