[postgis-users] irregular tiling with raster2pgsql - imported raster has nodata value on the edge

[Jakub Hettler]

Hi Bborie,
I think, that not all rasters are divisible without remainder (except 1x1
tile) :)

My problem is this (this is my raster after raster2psql displayed with
tiles)

http://sdrv.ms/OjbhoD

I need to cut the last tiles on the east and south a make it smaller by the
red line

But I think it is impossible now, but i will find the solution :)

I think about the function which will find the line of nodata value and
then I make the polygon and intersect it with this polygon. :D

But if I understand it, if I cut last tiles and these will be smaller than
others, I wont be able to load this raster into QGIS (PostGIS raster driver)

Thanks

Jakub



2012/8/26 Bborie Park <bkpark at ucdavis.edu>

> Currently, that behavior is as expected due to the application of the
> specified tile size from the upper-left corner.  To minimize the tiles
> with large swaths of NODATA, you should try to use a tile size that is
> cleanly divisible (no remainder) by the raster's width and height or a
> size with a large remainder.  I usually recommend tile sizes of
> 100x100 or smaller though sizes around 50x50 are even faster.  In
> terms of performance, the smaller the time size, the better the
> performance.
>
> -bborie
>
> On Sun, Aug 26, 2012 at 10:22 AM, Jakub Hettler <jakub.hettler at gmail.com>
> wrote:
> > Hi all,
> > I would like to ask if there is a way how to import tiled raster into
> > PostGIS through raster2pgsql, but I need to make tiled raster, say
> 256x256,
> > but at the end of raster I have last tiles (on the east and south side)
> > which is on half out of the original raster (raster ends fe in the
> middle of
> > last tile). If I try to load imported raster into QGIS or use
> gdal_translate
> > I have nodata value on this place in the raster. Is there a way how to
> > import the raster with the smaller last tiles on the east and south
> edges?
> >
> > Thanks
> >
> > Jakub
> >
> > _______________________________________________
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> >
>
>
>
> --
> Bborie Park
> Programmer
> Center for Vectorborne Diseases
> UC Davis
> 530-752-8380
> bkpark at ucdavis.edu
> _______________________________________________
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>
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