Splitting/tiling a raster

[Bart van den Eijnden]

You can build overviews with gdaladdo:

http://www.gdal.org/gdal_utilities.html#gdaladdo

Eg:

gdaladdo -r average abc.tif 2 4 8 16

Try that first I would say.

Best regards,
Bart

Bart van den Eijnden
Syncera IT Solutions
Postbus 270
2600 AG  DELFT

tel.nr.: 015-7512436
email: BEN at Syncera-ITSolutions.nl

>>> Stefan Schwarzer <stefan.schwarzer at GRID.UNEP.CH> 07/12/05 12:02pm >>>

> Which format is your raster currently in?

TIF or JPEG

>
> If it is performance, building overviews could also help for  
> certain situations.

So, how can I build overviews then?

>
> At which scales do you display your raster? Also at full extent?

 From full extent (at the beginning - a couple of hundreds km wide)  
to then, when zooming, a couple of km wide.

>
> Best regards,
> Bart
>
> Bart van den Eijnden
> Syncera IT Solutions
> Postbus 270
> 2600 AG  DELFT
>
> tel.nr.: 015-7512436
> email: BEN at Syncera-ITSolutions.nl 
>
>
>>>> Stefan Schwarzer <stefan.schwarzer at GRID.UNEP.CH> 07/12/05  
>>>> 11:55am >>>
>>>>
> Thanks Bart for the quick response,
>
> aehh, yes, performance. But perhaps there is no need to split it up?
> Is it that what you mean? Gush, somehow I don't really get it how
> this tiling works, stupid me....
>
> Stef
>
>
>
>> Hi Stefan,
>>
>> since gdal_translate has the option to select a subwindow (srcwin)
>> from your sourcefile, you can use it to split your raster file into
>> subimages.
>>
>> http://www.gdal.org/gdal_utilities.html#gdal_translate 
>>
>> After that, you do use gdaltindex to create a tileindex. That part
>> is described in the raster howto:
>>
>> http://mapserver.gis.umn.edu/doc44/raster-howto.html 
>>
>> Btw, what is the exact reason you want to split up your raster?
>> Performance?
>>
>> Best regards,
>> Bart
>>
>> Bart van den Eijnden
>> Syncera IT Solutions
>> Postbus 270
>> 2600 AG  DELFT
>>
>> tel.nr.: 015-7512436
>> email: BEN at Syncera-ITSolutions.nl 
>>
>>
>>
>>>>> Stefan Schwarzer <stefan.schwarzer at GRID.UNEP.CH> 07/12/05
>>>>> 11:39am >>>
>>>>>
>>>>>
>> Hi,
>>
>> this subject is really not new. But I haven't found any real how-to
>> for the whole story. Perhaps somebody could clarify the steps needed.
>> when starting with an image of some larger size and when ending with
>> a tiled raster. Cause I guess that' what has to be done.
>> - At least I have now one single big raster. As far as I understood I
>> need to split the big image into smaller ones. But how?
>> - And then I can use gdaltindex to build the shapefile to define the
>> tiles. Right?
>>
>> Thanks for clarification.
>>
>>
>
>