Creating Diffence Image

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b. schitter

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Feb 14, 2022, 3:50:20 PM2/14/22
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Hello,

what's the simpliest way to create a fog diffence image?

It should be the diffence of IR3.9 - IR10.8.

Do I have to calculate the differnce for all the 3 colors (RGB) or is there another way?

Best regards,
Bernhard

Raspaud Martin

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Feb 15, 2022, 4:50:13 AM2/15/22
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Hi Bernhard,

One simple solution would be to use something like explained here:
https://satpy.readthedocs.io/en/stable/quickstart.html#creating-new-datasets
and then just save that dataset as an image (it will be black and white
if it is just the difference you mention)

If you want to have more control over the result, you can have you own
custom yaml composite config and enhancement config.

Maybe this part of the documentation can help too:
https://satpy.readthedocs.io/en/stable/composites.html#creating-composite-configuration-files

Best regards,
Martin

David Hoese

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Feb 15, 2022, 10:04:23 AM2/15/22
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Hi Bernhard,

For VIIRS data we actually have a composite builtin to Satpy that comes
from my Polar2Grid software. In Satpy it is called "ssec_fog" and is a
temperature difference between the I05 and I04 bands:

https://github.com/pytroll/satpy/blob/82112a60f843ad0d3fa32c6d49f224bcb00f28d7/satpy/etc/composites/viirs.yaml#L419-L424

Hope that can be used as a starting point.

Dave

b. schitter

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Feb 16, 2022, 12:52:54 AM2/16/22
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Hi Dave, hi Martin,

thank you for this hints. I could calculate the difference image. Now I want to enhance it.

The minimum value (-5) should have the color 255,255,153 and the max value (1) should have the color 0,0,128.

Is this possible in .../enhancements/generic.yaml?

Best regards,
Bernhard

Raspaud Martin

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Feb 16, 2022, 2:19:21 AM2/16/22
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Hi Bernhard,

Yes generic.yaml would be a good place to put your enhancement. For
giving a palette to apply, look for example here:
https://github.com/pytroll/satpy/blob/e72a3f029e6a94b55f48d894cbad20b1f4ef0562/satpy/etc/enhancements/viirs.yaml#L11-L48

Best regards,
Martin

Gis Geo

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Mar 8, 2022, 3:26:58 PM3/8/22
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Hi 
How create image RGB using python whit satellite meteosat 8
Best regards

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Raspaud Martin

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Mar 9, 2022, 3:29:18 AM3/9/22
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Hi,

If the data you have is in HRIT format, satpy can read it, and you can have a look here for instructions:
https://satpy.readthedocs.io/en/stable/quickstart.html

Best regards,
Martin

________________________________________
From: pyt...@googlegroups.com <pyt...@googlegroups.com> on behalf of Gis Geo <gis...@gmail.com>
Sent: 08 March 2022 21:26:44
To: pyt...@googlegroups.com
Subject: Re: [pytroll] Creating Diffence Image

Hi
How create image RGB using python whit satellite meteosat 8
Best regards

في الأربعاء، ١٦ فبراير، ٢٠٢٢ ١٠:١٩ ص Raspaud Martin <martin....@smhi.se<mailto:martin....@smhi.se>> كتب:
Hi Bernhard,

Yes generic.yaml would be a good place to put your enhancement. For
giving a palette to apply, look for example here:
https://github.com/pytroll/satpy/blob/e72a3f029e6a94b55f48d894cbad20b1f4ef0562/satpy/etc/enhancements/viirs.yaml#L11-L48

Best regards,
Martin

On Tue, 2022-02-15 at 21:52 -0800, b. schitter wrote:
> Hi Dave, hi Martin,
>
> thank you for this hints. I could calculate the difference image. Now
> I want to enhance it.
>
> The minimum value (-5) should have the color 255,255,153 and the max
> value (1) should have the color 0,0,128.
>
> Is this possible in .../enhancements/generic.yaml?
>
> Best regards,
> Bernhard
>
> dho...@gmail.com<mailto:dho...@gmail.com> schrieb am Dienstag, 15. Februar 2022 um 16:04:23
To unsubscribe from this group and stop receiving emails from it, send an email to pytroll+u...@googlegroups.com<mailto:pytroll%2Bunsu...@googlegroups.com>.
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Raspaud Martin

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Mar 9, 2022, 5:12:53 AM3/9/22
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Hi,

If the data you have is in HRIT format, satpy can read it, and you can
have a look here for instructions:
https://satpy.readthedocs.io/en/stable/quickstart.html

Best regards,
Martin

Gis Geo

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Mar 10, 2022, 5:27:32 PM3/10/22
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Hello dear, I have the data in netcdf format and I want to make an RGB image without going to the site or the archive. I just want to clarify how the air mass works in the anacoda program.
Best regards🙏

Raspaud Martin

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Mar 11, 2022, 2:23:10 AM3/11/22
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Hi,

I suppose it is netcdf format from the Eumetsat archive? I which case,
there is a reader for it (have a look at the reader table on the main
page on the satpy documentation).

The airmass product is described here:
https://www.eumetsat.int/media/41623

Best regards,
Martin
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