[gdal-dev] add tranperency

[Travis Kirstine]

Jan,

You may have some difficulties with creating a ECW output format with
gdalwarp, I would try GeoTiff first.  Also 3 band ECW have issues with
creation of compression artifacts in nodata areas so translating the
GeoTiff to ECW may not work as expected.

Regards

On 7 November 2011 13:36, Chaitanya kumar CH <chaitanya.ch at gmail.com> wrote:
> Jan,
>
> You can use the -srcnodata and -dstalpha options of gdalwarp[1] to set
> nodata values and create an alpha band to the image. You will have to give
> the value of the black borders with the -srcnodata option.
>
> [1]: http://www.gdal.org/gdalwarp.html
>
> On Mon, Nov 7, 2011 at 5:33 PM, Jan Tappenbeck <tappenbeck at widemann.de>
> wrote:
>>
>>
>>  Hi !
>>
>> i have a image with following data:
>>
>> C:\Program Files (x86)\FWTools2.4.7>gdalinfo "[Path]\trans_a.tif"
>> Driver: GTiff/GeoTIFF
>> Files: D:\brumi\VG_Bruchmuehlbach-Miesau_DOP\geotiff\trans_a.tif
>> Size is 10390, 10390
>> Coordinate System is:
>> PROJCS["DHDN / 3-degree Gauss-Kruger zone 2",
>>    GEOGCS["DHDN",
>>        DATUM["Deutsches_Hauptdreiecksnetz",
>>            SPHEROID["Bessel 1841",6377397.155,299.1528128000009,
>>                AUTHORITY["EPSG","7004"]],
>>            AUTHORITY["EPSG","6314"]],
>>        PRIMEM["Greenwich",0],
>>        UNIT["degree",0.0174532925199433],
>>        AUTHORITY["EPSG","4314"]],
>>    PROJECTION["Transverse_Mercator"],
>>    PARAMETER["latitude_of_origin",0],
>>    PARAMETER["central_meridian",6],
>>    PARAMETER["scale_factor",1],
>>    PARAMETER["false_easting",2500000],
>>    PARAMETER["false_northing",0],
>>    UNIT["metre",1,
>>        AUTHORITY["EPSG","9001"]],
>>    AUTHORITY["EPSG","31466"]]
>> Origin = (2601576.178792405400000,5477422.986974134100000)
>> Pixel Size = (0.200049845331526,-0.200049845331526)
>> Metadata:
>>  AREA_OR_POINT=Area
>> Image Structure Metadata:
>>  INTERLEAVE=PIXEL
>> Corner Coordinates:
>> Upper Left  ( 2601576.179, 5477422.987) (  7d24'1.33"E, 49d25'34.75"N)
>> Lower Left  ( 2601576.179, 5475344.469) (  7d23'59.41"E, 49d24'27.48"N)
>> Upper Right ( 2603654.697, 5477422.987) (  7d25'44.45"E, 49d25'33.49"N)
>> Lower Right ( 2603654.697, 5475344.469) (  7d25'42.50"E, 49d24'26.22"N)
>> Center      ( 2602615.438, 5476383.728) (  7d24'51.92"E, 49d25'0.49"N)
>> Band 1 Block=10390x1 Type=Byte, ColorInterp=Red
>> Band 2 Block=10390x1 Type=Byte, ColorInterp=Green
>> Band 3 Block=10390x1 Type=Byte, ColorInterp=Blue
>>
>> there are black arrows at the border (by transformation) - is it possible
>> to make i transparency ?
>>
>> how?
>>
>> gdal_translate -of ECW old_image.tif new_image.ecw
>>
>> tells that is unpossible !!!
>>
>> can you help me ?
>>
>> regards Jan :-)
>>
>>
>> _______________________________________________
>> gdal-dev mailing list
>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
>
>
> --
> Best regards,
> Chaitanya kumar CH.
>
> +91-9494447584
> 17.2416N 80.1426E
>
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