[gdal-dev] gdal_merge

[Clive Swan]

Greetings,

 I tried
-ps 3600 7200
 -ps 3600,7200
-ps x=3600  y=7200

Just get errors, I don't see any option to select LZW or any compression??

Extent -180.0000000000000000,-90.0000000000000000 :
> 180.0000000000000000,90.0000000000000000
> Width 7200
> Height 3600
> Data type Float32 - Thirty two bit floating point
>
Compression LZW

On Mon, 5 Dec 2022 at 12:32, Rahkonen Jukka <
jukka.rahkonen at maanmittauslaitos.fi> wrote:

> Hi,
>
>
>
> Let’s try to get all missing information with one mail.
>
>    - You have two images:
>    3_data_ready_for_spectra/coastal-undefended-rcp26-2020.tif and
>
> 5_UK_prod_rasters/coastal-undefended-rcp26-2020.tif.
>
> Is that right? And the first one covers the world but the second one only
> UK, right?
>
>    - What are the pixel sizes and image sizes (in pixels, width x hight)
>    of the source images?
>    - Are they compressed? With what method?
>    - What are the block sizes (out of curiosity, not essential knowledge)?
>    - Have you considered to create a tiled and compressed output? (you
>    should)
>    - Have you considered to use gdalwarp instead? (I would)
>
>
>
> With the gdalwarp option you could update the world image with the UK
> contents with “gdalwarp uk_image.tif world_image.tif”. However, your images
> are in AWS and the same recipes that work for local images may not work so
> well in the cloud. Unfortunately that is something that I have no
> experience yet.
>
>
>
> The logic in “The input files are 6.9 GB + 672 MB The output should be
> 7.xx GB” is wrong. If you update part of the pixels of the 6.9 GB file then
> the output should be about 6.9 GB. But if you convert a 6.9 GB compressed
> image into an uncompressed image, as I guess that you are doing, the output
> will be much bigger. How big it will be can be calculated with a formula
> that numpy showed (width x height) x (bytes/pixel).
>
>
>
> -Jukka Rahkonen-
>
>
>
> *Lähettäjä:* Clive Swan <cliveswan at gmail.com>
> *Lähetetty:* maanantai 5. joulukuuta 2022 13.47
> *Vastaanottaja:* Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi>;
> gdal-dev at lists.osgeo.org
> *Aihe:* Re: [gdal-dev] gdal_merge
>
>
>
> Hi,
>
>
>
> The raster one is the world, the second is the UK.
>
> The UK fits within the first raster...
>
>
>
> We want to update UK data in raster one.
>
>
>
> Regards,
>
>
>
> Clive
>
>
>
> Get Outlook for Android
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> ------------------------------
>
> *From:* Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi>
> *Sent:* Monday, December 5, 2022 11:34:53 AM
> *To:* Clive Swan <cliveswan at gmail.com>; gdal-dev at lists.osgeo.org <
> gdal-dev at lists.osgeo.org>
> *Subject:* Re: [gdal-dev] gdal_merge
>
>
>
> Hi,
>
>
>
> Maybe your rasters are far apart. Gdal_merge creates a raster with so
> large extent that all the source images fit within it. Even empty pixels
> take space.
>
>
>
> -Jukka Rahkonen-
>
>
>
>
>
> *Lähettäjä:* gdal-dev <gdal-dev-bounces at lists.osgeo.org> *Puolesta *Clive
> Swan
> *Lähetetty:* maanantai 5. joulukuuta 2022 12.24
> *Vastaanottaja:* gdal-dev at lists.osgeo.org
> *Aihe:* [gdal-dev] gdal_merge
>
>
>
> Hi Even,
>
>
>
> Thanks
> the –configuration sorted out that issue.
>
> CPL_VSIL_USE_TEMP_FILE_FOR_RANDOM_WRITE is a configuration option /
>
> environment variable, so you have to pass it with --config
>
> CPL_VSIL_USE_TEMP_FILE_FOR_RANDOM_WRITE YES
>
>
>
> Now I am getting a memory issue?? << The input files are 6.9 GB + 672 MB
> The output should be 7.xx GB
>
>
>
> 6.9 GB + 672MB
>
> numpy.core._exceptions._ArrayMemoryError: Unable to allocate 377. GiB for
> an array with shape (225000, 450000) and data type float32
>
>
>
> Any suggestions appreciated
>
> Kind regards,
>
> Clive
>
>
>
> --
>
>  Regards,
>
>
>
> Clive Swan
>
> --
>


-- 

 Regards,


Clive Swan

--


M: +44 7766 452665
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