[GRASS-dev] r.in.gdal changes range of values for sentinel bands (?)

[Markus Metz]

On Mon, Feb 5, 2018 at 1:14 PM, Veronica Andreo <veroandreo at gmail.com>
wrote:
>
> I tested also with 74 release branch... same result
>
> 2018-02-05 13:05 GMT+01:00 Veronica Andreo <veroandreo at gmail.com>:
>>
>> Hi devs
>>
>> I'm testing Martin's new add-on, r.sentinel.import. I created an UTM21S
location for my data and imported them with:
>>
>> r.sentinel.import
input=Downloads/S2B_MSIL1C_20171212T134159_N0206_R124_T21KZP_20171212T201017.SAFE/GRANULE/L1C_T21KZP_A004011_20171212T134158/IMG_DATA/
>>
>> The problem arose when I tried to use i.color.enhance to display an RGB:
I got blank screens, so I thought there must be something with the range of
values.
>>
>> r.univar map=T21KZP_20171212T134159_B02 at PERMANENT

>> total null and non-null cells: 120560400
>> total null cells: 0
>> Of the non-null cells:
>> ----------------------
>> n: 120560400
>> minimum: 15
>> maximum: 17547
>> range: 17532
>> mean: 913.778
>> mean of absolute values: 913.778
>> standard deviation: 134.322
>> variance: 18042.4
>> variation coefficient: 14.6996 %
>> sum: 110165471238
>>
>> that already seemed odd...
>> I checked the original band2 jp2 file... Values are different...
>>
>> gdalinfo T21KZP_20171212T134159_B02.jp2
>> Driver: JP2OpenJPEG/JPEG-2000 driver based on OpenJPEG library
>> Files: T21KZP_20171212T134159_B02.jp2
>> ...
>> Band 1 Block=1024x1024 Type=UInt16, ColorInterp=Gray
>>   Min=602.000 Max=1576.000
>>   Minimum=602.000, Maximum=1576.000, Mean=916.799, StdDev=123.509
>>   Overviews: 5490x5490, 2745x2745, 1372x1372, 686x686
>>   Overviews: arbitrary
>>   Metadata:
>>     STATISTICS_MAXIMUM=1576
>>     STATISTICS_MEAN=916.7992
>>     STATISTICS_MINIMUM=602
>>     STATISTICS_STDDEV=123.50943477872
>>   Image Structure Metadata:
>>     COMPRESSION=JPEG2000
>>     NBITS=15

Can you try again with gdalinfo -mm? This forces computation of the actual
min/max values, which can differ from what is stored in the metadata (an
approximation).

There can also be something wrong with i.color.enhance

Markus M

>>
>> Just to check, I imported with r.in.gdal and I'm getting exactly the
same as with r.sentinel.import.
>>
>> What am I doing wrong here? Why would r.in.gdal change values like that?
What else needs to be set? I don't remember to have this problem before and
it happens in all bands as far as I've checked.
>>
>> Ah, I'm using trunk r72203
>>
>> Thanks in advance for any help :)
>>
>> Cheers,
>> Vero
>>
>>
>>
>
>
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