GeoTIFF Export

ILAP
ILAP
in Raster Data
in Version V18.0.3 in Export raster as GeoTIFF there in the TIFF Format Options there is no option for JPEG Compression even though the HELP shows it should be there. In that case I do not understand if and how the "ADVANCED: JPEG-in-TIFF Quality" is working?
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Answers

  • bmg_bob
    bmg_bob Global Mapper Programmer
    Hello,

    JPEG Compression is only supported when exporting RGB raster images (not palette images or elevation data).  What type of data are you trying to export?

    Cheers,
    Bob
  • ILAP
    ILAP
    edited February 2017
    I am trying to export GeoTIFF Orthophoto created by Pix4D. The GeoTIFF that Pix4D creates is very large and I want to export it with a compression that would make it smaller without affecting the resolution
  • bmg_bob
    bmg_bob Global Mapper Programmer
    ILAP said:
    I am trying to export GeoTIFF Orthophoto created by Pix4D. The GeoTIFF that Pix4D creates is very large and I want to export it with a compression that would make it smaller without affecting the resolution
    What workflow are you currently using?  Can you post a screen capture of your export options screen?

    Cheers,
    Bob
  • ILAP
    ILAP
    edited February 2017
    Here is screen capture
  • bmg_bob
    bmg_bob Global Mapper Programmer
    edited February 2017
    Hello,

    It appears that you are exporting a palette image.  JPEG Compression is only available when you export a 24-bit RGB image.

    It is possible that you don't need the JPEG compression if you are exporting an 8-bit palette image.  The palette image would be relatively small without compression.

    Cheers,
    Bob
  • ILAP
    ILAP
    For this Orthophoto I get 4.5 GB GeoTIFF while saving this same Orthophoto as ECW I get 600 MB file.
    Is there any way to make the GeoTIFF smaller?
    BTW - it had to be saved as BigTIFF since it is over 4 GB. Should that matter in any way?
  • bmg_bob
    bmg_bob Global Mapper Programmer
    edited February 2017
    ILAP said:
    For this Orthophoto I get 4.5 GB GeoTIFF while saving this same Orthophoto as ECW I get 600 MB file.
    Is there any way to make the GeoTIFF smaller?
    BTW - it had to be saved as BigTIFF since it is over 4 GB. Should that matter in any way?
    GeoTIFF is not really suitable for a data set that is that large.  Do you have any other options?  ECW and JP2 are compressed formats that are designed to handle large data sets.

    Do you have to produce a single output data set?  You can also try tiling the data to produce several smaller GeoTIFFs.

    The BigTIFF format is distinct from GeoTIFF.  There is no guarantee that programs that can read GeoTIFF will also be able to read BigTIFF.

    Cheers,
    Bob
  • geomaticist
    geomaticist
    I always preserve original raster data in tiff format, but use ecw as a down stream deliverable. In other words, save it, then make an ecw and it is very good. usually can use compression level 4 and not even 'see' a difference. When you need to you go back to the tiff for making new clips. If you compress ecw, then open and export as ecw again be careful to not compress it further ... that's where I just return to the tiff.

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