Hi, I asked a few questions and hoped we could solve your problem with one mail if you answered them all but probably we need more. Here is an example about the info I would like to see. You can obtain it with gdalinfo gdalinfo test.tif ... Size is 12000, 12000 ... Pixel Size = (0.500000000000000,-0.500000000000000) ... COMPRESSION=YCbCr JPEG ... Band 1 Block=256x256 Type=Byte, ColorInterp=Red
The -ps stands for pixel size https://gdal.org/programs/gdal_merge.html#cmdoption-gdal_merge-ps. Thus, how many meters or degrees one pixel is wide/high. Gdal_merge does not have an option for defining the size of the output image in pixels. See my example about half-a-metre pixels above, that is the information that you need. Do not pay attention to negative Y size, use positive number for both directions with gdal_merge. Do not get surprised by the small number that you will probably see, I guess your image in in EPSG:4326 and the units are degrees. Compression options are format specific, for GeoTIFF read https://gdal.org/drivers/raster/gtiff.html. With gdal_merge read https://gdal.org/programs/gdal_merge.html#cmdoption-gdal_merge-co and add for example "-co COMPRESS=LZW -co TILED=YES" into the command. -Jukka Rahkonen- Lähettäjä: Clive Swan <[email protected]> Lähetetty: maanantai 5. joulukuuta 2022 15.32 Vastaanottaja: Rahkonen Jukka <[email protected]> Kopio: [email protected] Aihe: Re: [gdal-dev] gdal_merge 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 <[email protected]<mailto:[email protected]>> 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 <[email protected]<mailto:[email protected]>> Lähetetty: maanantai 5. joulukuuta 2022 13.47 Vastaanottaja: Rahkonen Jukka <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]> 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<https://eur06.safelinks.protection.outlook.com/?url=https%3A%2F%2Faka.ms%2FAAb9ysg&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7Ca53f6e33f709481cefa008dad6c51040%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C638058439123548735%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=NbhnxmobPMAi%2F%2FrcmPjSwtbKHyRqxAriD5MNJe4CSXA%3D&reserved=0> ________________________________ From: Rahkonen Jukka <[email protected]<mailto:[email protected]>> Sent: Monday, December 5, 2022 11:34:53 AM To: Clive Swan <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> 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 <[email protected]<mailto:[email protected]>> Puolesta Clive Swan Lähetetty: maanantai 5. joulukuuta 2022 12.24 Vastaanottaja: [email protected]<mailto:[email protected]> 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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