[Qgis-user] R: Importing a raster into a Geopackage
Kirk Schmidt
kirk at nortekresources.com
Tue Dec 1 10:58:12 PST 2020
Hi Nicolas
I did the same and the legend indicates a change magnitude but if I
subtract the geopackage raster from the original, all pixels equal zero.
Kirk
On 12/1/2020 2:36 PM, Nicolas Cadieux wrote:
>
> Hi,
>
> Tried this:
>
> gdal_translate -of GPKG -b 1
> C:/Users/Nicolas/Desktop/Land_cover_Corine2018.tif
> C:/Users/Nicolas/Desktop/test.gpkg
>
> I read 4 band and still get data modifications.
>
> Nicolas
>
> On 2020-12-01 1:28 p.m., Kirk Schmidt wrote:
>>
>> 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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> --
> 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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