[mapguide-users] raster ECW transparency

[Johan Van de Wauw]

Ok, I remember things better now: older versions of ecw do not support
transparency. If you use tif it will work in mapguide/AIMS, but your
filesizes will explode.
Actually we solved this problem by not using transparent ecw files but by
overlaying these transparent tiffs with with other images (of a lower
resolution) we had in the background and exporting that result as ecw.

Johan


On Tue, Feb 5, 2013 at 12:37 PM, Jérôme DUCKERS <jerome.duckers at gmail.com>wrote:

> Hi thanks Johan,
>
> I'm working too with AIMS, Gdal was a test.
>
> I have tried your command, but for the moment, the result is the same that
> i have for the moment, a cloud.
> What soft are you using for conversion ?
> We are using Erdas Imagine.
>
> I took a tif, then i generate an Ecw (with erdas imagine)
> I use your command.
> And finaly, i regenerate my Ecw based on my new tif.
>
> With Autocad Map3d, i see that my tiff is right (i can do transparency on
> white color), but when my tiff is converted,
> i apply the transparency on white, and i see a cloud near my image
>
> it's very difficult :'(
>
>
>
> 2013/2/5 Zac Spitzer <zac.spitzer at gmail.com>
>
>> if you need some GDAL improvements, you could always engage Trevor to
>> make them
>>
>>
>> On Tue, Feb 5, 2013 at 9:57 AM, Johan Van de Wauw <
>> johan.vandewauw at gmail.com> wrote:
>>
>>> I've not used the GDAL provider myself, but using AIMS raster driver the
>>> only way I found to make ecw transparent was adding a alpha layer. I did
>>> this using the gdal command line utility "nearblack" with the setalpha
>>> option:
>>> nearblack -setalpha -o out.tif in.ecw
>>> And afterwards converting the output to ecw again (exporting to ecw was
>>> not supported by nearblack).
>>>
>>> Johan
>>>
>>>
>>>
>>> On Mon, Feb 4, 2013 at 5:27 PM, StuartSteel <
>>> stuart.steel at atkinsglobal.com> wrote:
>>>
>>>> Bump.
>>>>
>>>> I cannot believe that Duck and myself are the only two people who
>>>> require
>>>> nodata transparency using the GDAL raster provider?
>>>>
>>>> Can anyone shed some light on this, please?
>>>>
>>>>
>>>>
>>>> --
>>>> View this message in context:
>>>> http://osgeo-org.1560.n6.nabble.com/raster-ECW-transparency-tp5029485p5032030.html
>>>> Sent from the MapGuide Users mailing list archive at Nabble.com.
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>>>
>>>
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>>
>>
>> --
>> Zac Spitzer
>> Solution Architect / Director
>> Ennoble Consultancy Australia
>> +61 405 847 168
>>
>>
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>>
>
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