[Cartoweb-users] ECW

Bruno Friedmann bruno at ioda-net.ch
Sat Jun 12 01:56:35 EST 2010

Hi Simone, today I found this remark about tiles. I really suspect that's related to yours nodata/black background

This dimension is a good compromise allowing efficient raster/vector analysis. It is better if the size of the tiles is a
divider of the size of each raster. Otherwise the last columns and rows of tiles of each raster will be filled with nodata values.


On 06/11/2010 08:01 PM, Bruno Friedmann wrote:
> On 06/11/2010 07:25 PM, Simone Frigerio wrote:
>> Ya Bruno, was exactly that problem! Thanks.
>> The only problem is now how to manage external black background created
>> aftter ECW or JP2 compression (original heavy tiff files didn't have it,
>> but simply NoData). I need to solve out cartoweb framework, I suppose.
>> Do you have any idea?
>> Special thanks.
> better to answer to list ... so everybody enjoy solutions
> I suspect it's more mapserver related than cw3.
> with the help of shp2img you can get directly what mapserver return
> ( you have to simulate the checked layers etc ) It could be hard to make ecw & mapserver properly linked together
> depending on what OS you are using.
> Also if ecw take less space on disk, each time you need them mapserver has to uncompress them in ram.
> So a judicious calculation between the time loss and/or place should be done.
> If you try to import your ecw files inside a soft like udig, qgis did you get also the black background ?
> I didn't really know well all ecw problematic, so perhaps someone else can drive you to the right way.


     Bruno Friedmann

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