[HN Gopher] Smaller Satellite Images
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       Smaller Satellite Images
        
       Author : marklit
       Score  : 30 points
       Date   : 2024-12-01 09:53 UTC (1 days ago)
        
 (HTM) web link (tech.marksblogg.com)
 (TXT) w3m dump (tech.marksblogg.com)
        
       | kelseyfrog wrote:
       | Better compression schemes for GeoTIFFs is great and all - I'm
       | not going to complain about that; however, I'd like to add a
       | little more context from a data engineering perspective
       | especially for data in transit.
       | 
       | As we all know, the best way to speed up some processes is by
       | avoiding the step entirely, and as much as better compression
       | schemes for GeoTIFFs shrink transport sizes, avoiding transfer of
       | rasters reduces the cost to zero. Internally tiled GeoTIFFs
       | (Cloud Optimized GeoTIFFs[1] in particular) allow portions of
       | GeoTIFFs to be read using range reads instead. This can
       | dramatically reduce transfer costs when only sections of the
       | raster are required and pair well when used with vector data for
       | look ups. In the specific case used by the author, omitting
       | water-only tiles would potentially cut transfer costs by half.
       | 
       | Additionally, if using multi-spectral imagery, band re-ordering
       | can be an important subsequent optimization if certain indices
       | are known in advance to be used dis-proportionally more. There's
       | a lot of fun to be had in optimizing the heck out of imagery data
       | and this barely scratches the surface.
       | 
       | 1. https://cogeo.org/
        
       | mistrial9 wrote:
       | webp ?
        
       | unwind wrote:
       | Ah, the "My Workstation" guy. I wonder if that text could be
       | factored out and linked to in a sidebar or something (it's in
       | every article I've seen from him, here).
        
         | progbits wrote:
         | Presumably the workstation changes over time :)
         | 
         | I like benchmarks that properly describe their environment for
         | posterity.
        
           | fourteenfour wrote:
           | Sure, to me it seems overly verbose in ways that are not
           | relevant to the article.
           | 
           | 6 GHz i9-14900K CPU
           | 
           | Nvidia GTX 1080 GPU
           | 
           | 96 GB of DDR5 RAM
           | 
           | ASRock Z790 Pro RS Motherboard
           | 
           | Crucial T700 4 TB NVMe M.2 SSD
           | 
           | 1,200-watt Corsair Power Supply
           | 
           | Ubuntu 22 LTS via Microsoft's Ubuntu for Windows on Windows
           | 11 Pro
        
       | jarl-ragnar wrote:
       | I followed a similar approach recently to create map layers with
       | Sentinel-2 imagery.
       | 
       | Webp encoded tiles extracted from the CoGs available on AWS then
       | embedded within a pmtiles file.
       | 
       | I was seeing almost an order of magnitude reduction in file size
       | compared to the CoGs with no visible image degradation.
        
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       (page generated 2024-12-02 23:01 UTC)