GeoTools
  1. GeoTools
  2. GEOT-1644

Add support for external overviews raster format

    Details

      Description

      GDAL apparently learned to support external overviews lately, that's a very nice capability that significantly speeds up rendering.
      The free Merano mosaic for example has them, here is the result of gdalinfo on them:

      C:\progetti\gisData\merano\jpg>gdalinfo 01.jpg
      Driver: JPEG/JPEG JFIF
      Files: 01.jpg
             01.aux
             01.rrd
      Size is 6750, 6000
      Coordinate System is `'
      Origin = (663341.701881218350000,5173420.982341781300000)
      Pixel Size = (0.100000000000000,-0.100000000000000)
      Image Structure Metadata:
        INTERLEAVE=PIXEL
        COMPRESSION=JPEG
      Corner Coordinates:
      Upper Left  (  663341.702, 5173420.982)
      Lower Left  (  663341.702, 5172820.982)
      Upper Right (  664016.702, 5173420.982)
      Lower Right (  664016.702, 5172820.982)
      Center      (  663679.202, 5173120.982)
      Band 1 Block=6750x1 Type=Byte, ColorInterp=Red
        Overviews: 1686x1498, 842x748, 420x373, 209x185, 103x91, 50x44
        Metadata:
          LAYER_TYPE=athematic
        Image Structure Metadata:
          COMPRESSION=JPEG
      Band 2 Block=6750x1 Type=Byte, ColorInterp=Green
        Overviews: 1686x1498, 842x748, 420x373, 209x185, 103x91, 50x44
        Metadata:
          LAYER_TYPE=athematic
        Image Structure Metadata:
          COMPRESSION=JPEG
      Band 3 Block=6750x1 Type=Byte, ColorInterp=Blue
        Overviews: 1686x1498, 842x748, 420x373, 209x185, 103x91, 50x44
        Metadata:
          LAYER_TYPE=athematic
        Image Structure Metadata:
          COMPRESSION=JPEG
      

      Well, this said, I have no idea how hard adding direct support in java would be... but I guess this would be a good reason to have a gdal based jpeg reader? (btw, notice how overviews are missing the intermediate level between 6750 and 1686 here too, using the highest lower resolution policy for picking the best overview would be bad here too).

        Activity

        Hide
        Andrea Aime added a comment -
        I'm wondering, did you have the .aux and .rrd files in your tests with imagemagick too? Would it be possible that imagemagick was faster because it was reading the overviews?
        Show
        Andrea Aime added a comment - I'm wondering, did you have the .aux and .rrd files in your tests with imagemagick too? Would it be possible that imagemagick was faster because it was reading the overviews?
        Hide
        Andrea Aime added a comment -
        Daniele, haven't you just committed a patch fixing this old report?
        Show
        Andrea Aime added a comment - Daniele, haven't you just committed a patch fixing this old report?
        Hide
        Simone Giannecchini added a comment -
        this is supported on 8.x and 2.7.x for geotiff
        Show
        Simone Giannecchini added a comment - this is supported on 8.x and 2.7.x for geotiff

          People

          • Assignee:
            Simone Giannecchini
            Reporter:
            Andrea Aime
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            Dates

            • Created:
              Updated: