[gdal-dev] gdal_translate -scale

[Rahkonen Jukka (MML)]

Hi,

Please remember to use reply-to-all for sending a copy to the list as well.

-Jukka-

-----Alkuperäinen viesti-----
Lähettäjä: jesus.moran at solute.es <jesus.moran at solute.es> 
Lähetetty: maanantai 14. joulukuuta 2020 14.27
Vastaanottaja: Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi>
Aihe: RE: [gdal-dev] gdal_translate -scale

Hi,

Thank you so much for your quick response. I can see the issue here. My data is 16 bits so it can be omitted in the -scale param. I will have to look for Python aid as you said, then.

Have a nice Monday! 




Jesús Maria Morán Rosado
Project Engineer
 
Av. Cerro del Águila, 3, 28703 S.S. de los Reyes, Madrid
CONFIDENTIALITY: This e-mail and any attachments are confidential and may be privileged. If you are not a named recipient, please notify the sender immediately and do not disclose the contents to another person, use it for any purpose or store or copy the information in any medium.

-----Original Message-----
From: gdal-dev <gdal-dev-bounces at lists.osgeo.org> On Behalf Of jratike80
Sent: lunes, 14 de diciembre de 2020 13:18
To: gdal-dev at lists.osgeo.org
Subject: Re: [gdal-dev] gdal_translate -scale

Hi,

If your output is 8 bit you can just use -scale without min/max values.
From https://gdal.org/programs/gdal_translate.html:

"Rescale the input pixels values from the range src_min to src_max to the range dst_min to dst_max. If omitted the output range is 0 to 255. If omitted the input range is automatically computed from the source data."

If your data is higher than 8 bit and you want to keep it so you are out of luck with gdal_translate because it first omits the output range and sets it into 0-255 before it can omit the input range and compute the range automatically.

The current behavior is not optimal for certain use cases (https://gis.stackexchange.com/questions/294129/min-max-stretch-using-gdal-translate-in-a-batch).
Some programmer learning GDAL could take this as a challenge and formulate how to improve the automatic scaling support so that it would not break too much. As a first aid a Python script for automatic min/max scaling would be nice, and why not with an option to utilize the histogram and use for example +/- 98% of the histogram. Or mean +/- (2 x RMS).

-Jukka Rahkonen-



jesus.moran wrote
> Hello GDAL team and thank you for welcome me.
> 
>  
> 
> I have an issue with the gdal_translate command. I would like to use 
> the “STATISTICS_MIN” and “STATISTICS_MAX” metadata key values in the 
> -scale parameter of the program, so I don’t need to specify it 
> manually every time I want to scale the output. Is there any way to do 
> this?
> 
>  
> 
> Thanks a lot in advance!
> 
>  
> 
> 
>  <http://www.solute.es/>
> 
> 
> Jesús Maria Morán Rosado
> Project Engineer
> 
> Av. Cerro del Águila, 3, 28703 S.S. de los Reyes, Madrid
> 
> CONFIDENTIALITY: This e-mail and any attachments are confidential and 
> may be privileged. If you are not a named recipient, please notify the 
> sender immediately and do not disclose the contents to another person, 
> use it for any purpose or store or copy the information in any medium.
> 
>  
> 
> 
> _______________________________________________
> gdal-dev mailing list

> gdal-dev at .osgeo

> https://lists.osgeo.org/mailman/listinfo/gdal-dev
> 
> 
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