[Qgis-user] R: Importing a raster into a Geopackage
Kirk Schmidt
kirk at nortekresources.com
Tue Dec 1 10:28:39 PST 2020
Hi Nicolas:
try the -b 1 parameter. I just tried this and wrote a single band
raster from a 3 channel tiff.
Kirk
On 12/1/2020 2:03 PM, Nicolas Cadieux wrote:
>
> I tried
>
> gdal_translate -of GPKG -co "BAND_COUNT=1"
> C:/Users/Nicolas/Desktop/Land_cover_Corine2018.tif
> C:/Users/Nicolas/Desktop/TEST.gpkg for the creation and
>
> C:\>gdal_translate -of GPKG -co "TILE_FORMAT = TIFF"
> C:/Users/Nicolas/Desktop/Land_cover_Corine2018.tif
> C:/Users/Nicolas/Desktop/TEST.gpkg
>
> Same problem. I wonder if we need to change the reading options...
> https://gdal.org/drivers/raster/gpkg.html
>
>
> "Opening options
>
> By default, the driver will expose a GeoPackage dataset as a four band
> (Red,Green, Blue,Alpha) dataset, which gives the maximum compatibility
> with the various encodings of tiles that can be stored. It is possible
> to specify an explicit number of bands with the BAND_COUNT opening
> option."
>
> The problem could be when QGIS Reads the file, not when it writes the
> file. I explains why we see 4 bands but not why values are changing.
> I would make a bug report or ask the question on the gdal dev group to
> get Even Rouault's attention.
>
> Nicolas
>
>
> On 2020-12-01 12:17 p.m., Sebastian Gutwein wrote:
>> This looks like the same issue you are having.
>> github.com/qgis/QGIS/issues/38227
>> <http://github.com/qgis/QGIS/issues/38227>
>> According to the documentation linked in the issue you need to set
>> the band count to 1 otherwise it defaults to 4.
>> gdal.org/drivers/raster/gpkg.html
>> <http://gdal.org/drivers/raster/gpkg.html>
>> I have not tried this to see if it works.
>>
>> On Tue, Dec 1, 2020 at 11:52 AM Nicolas Cadieux
>> <njacadieux.gitlab at gmail.com <mailto:njacadieux.gitlab at gmail.com>> wrote:
>>
>> Hi,
>>
>> Looking at it now. I see what you see. I will try a few things.
>>
>> Nicolas
>>
>> On 2020-12-01 11:42 a.m., Alberto Vavassori wrote:
>>>
>>> Hi Nicolas,
>>>
>>> thank you for the answer. I send the raster that I am interested in.
>>>
>>> Alberto
>>>
>>> *Da:*Nicolas Cadieux <njacadieux.gitlab at gmail.com>
>>> <mailto:njacadieux.gitlab at gmail.com>
>>> *Inviato:* martedì 1 dicembre 2020 17:40
>>> *A:* Alberto Vavassori <alberto.vavassori at polimi.it>
>>> <mailto:alberto.vavassori at polimi.it>
>>> *Cc:* qgis-user at lists.osgeo.org <mailto:qgis-user at lists.osgeo.org>
>>> *Oggetto:* Re: [Qgis-user] Importing a raster into a Geopackage
>>>
>>> Hi,
>>>
>>> Send a sample data set if you can't figure it out.
>>>
>>> Nicolas
>>>
>>> On 2020-12-01 10:35 a.m., Nicolas Cadieux wrote:
>>>
>>> Hi,
>>>
>>> Perhaps this can help:
>>> https://gdal.orgdrivers/raster/gpkg.html
>>> <https://gdal.orgdrivers/raster/gpkg.html>
>>>
>>> “Various kind of input datasets can be converted to
>>> GeoPackage raster :
>>>
>>> ·Single band grey level
>>>
>>> ·Single band with R,G,B or R,G,B,A color table
>>>
>>> ·Two bands: first band with grey level, second band with
>>> alpha channel
>>>
>>> ·Three bands: Red, Green, Blue
>>>
>>> ·Four band: Red, Green, Blue, Alpha
>>>
>>> GeoPackage rasters only support Byte data type.”
>>>
>>> My guess is that if the original raster does not correspond
>>> to one of the categories above, it will be converted to the
>>> closest format.
>>>
>>> Nicolas Cadieux
>>>
>>> https://gitlab.com/njacadieux <https://gitlab.com/njacadieux>
>>>
>>>
>>>
>>> Le 1 déc. 2020 à 09:58, Alberto Vavassori
>>> <alberto.vavassori at polimi.it>
>>> <mailto:alberto.vavassori at polimi.it> a écrit :
>>>
>>>
>>>
>>> Hello everybody. I have an issue regarding the
>>> Geopackage format. I have tried to import a singleband
>>> raster file (it represents the land cover, thus every
>>> pixel has a single integer value corresponding to the
>>> land cover class), but this operation seems to modify
>>> the raster characteristics: the raster becomes a 4-bands
>>> raster and the pixels values change accordingly
>>> (basically, the original raster is saved in the
>>> Geopackage as an RGB image). It seems to be a bug of
>>> QGIS. I have also tried to use GDAL translate through
>>> the processing toolbox of QGIS to convert the TIFF file
>>> to a Geopackage file, but the result is the same.
>>>
>>> Has anybody faced this problem? May anybody suggest a
>>> way to work this problem out?
>>>
>>> Thank you.
>>>
>>> Alberto
>>>
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>>> --
>>> Nicolas Cadieux
>>> https://gitlab.com/njacadieux <https://gitlab.com/njacadieux>
>>
>> --
>> Nicolas Cadieux
>> https://gitlab.com/njacadieux <https://gitlab.com/njacadieux>
>>
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> --
> Nicolas Cadieux
> https://gitlab.com/njacadieux
>
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--
Kirk Schmidt, MScF, BScF, RPF
General Manager
Nortek Resource Solutions Inc.
RR # 1
Thorburn, NS
B0K 1W0
Tel (902) 922.3607
Email: kirk at nortekresources.com
Web: www.nortekresources.com
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