[Qgis-user] R: Importing a raster into a Geopackage
Nicolas Cadieux
njacadieux.gitlab at gmail.com
Tue Dec 1 11:03:07 PST 2020
Same here, very different results
https://drive.google.com/file/d/1GyIhYMWSdZFtI4uHQOLOyJpmcqDLrx4K/view?usp=sharing
I'am on 3.16.1, Window 10
Nicolas
On 2020-12-01 1:58 p.m., Kirk Schmidt wrote:
>
> 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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--
Nicolas Cadieux
https://gitlab.com/njacadieux
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