[postgis-devel] [WKT Raster] Regular blocking in gdal2wktraster.py

[Mateusz Loskot]

Pierre Racine wrote:
> Mateusz Loskot wrote:
>> Pierre Racine wrote:
>>> You could have used gdal_retile.py to create a bunch of 
>>> filesystem tiles and import them with the wilcard. This is what I
>>>  did when I first imported my 3600 100x100 tiles three weeks ago.
>>> 
>>> 
>> Note, that -k uses size of "natural" block which is provided by 
>> GDAL.
> 
> What are these "sizes of "natural" block"?

>From GDAL manual:

"The block size is used to establish a natural or efficient block size
to access the data with. For tiled datasets this will be the size of a
tile, while for most other datasets it will be one scanline, as in this
case."

> If an image is not internally tiled, does GDAL retile it to "natural 
> blocks"? "Natural" for GDAL is not necessarily "natural" for my 
> purpose depending if I an building a desktop application, a web 
> application or merely using WKT Raster to do vector/raster analysis 
> (I can do amazing things with PostGIS that I can't do with ArcGIS. 
> PostGIS is fast and handle very big datasets). I will probably want 
> to retile my datasets to different tiles size until I find the size 
> that make threatment as fast as it can be. ...like you save your JPEG
>  files to a certain quality until you are happy with the way they
> look and the spead they download. For the moment I have no idea what
> will be the "best" tile size for my application.

We've already managed to solve this part of our raster sudoku :-)
and agree that we should be able to call gdal2wktraster specifying
custom raster block, overriding what block size reported by GDAL.

Best regards
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org