[gdal-dev] gdaladdo slowness for VRTs

Tue Jun 4 18:35:38 PDT 2024

Hi,

I spotted a slow calculation of overviews and I'm wondering what could be
the reason.

$ gdal_create in.tif -if 20240602_230818_SN26_RR_VISUAL_MS.vrt
$ time gdaladdo -ro in.tif

gdaladdo -ro in.tif  4,25s user 6,23s system 34% cpu 30,623 total

But on the file of the same size and num of bands but VRT it takes much
more time:

$ time gdaladdo -ro 20240602_230818_SN26_RR_VISUAL_MS.vrt
gdaladdo -ro   55,36s user 5,06s system 44% cpu 2:14,79 total

Here is the output of gdalinfo of the VRT:

$ gdalinfo 20240602_230818_SN26_RR_VISUAL_MS.vrt
Driver: VRT/Virtual Raster
Files: 20240602_230818_SN26_RR_VISUAL_MS.vrt
       20240602_230818_SN26_RR_VISUAL_MS_340_5020.tif
       20240602_230818_SN26_RR_VISUAL_MS_340_5040.tif
       20240602_230818_SN26_RR_VISUAL_MS_360_5020.tif
       20240602_230818_SN26_RR_VISUAL_MS_360_5040.tif
       20240602_230818_SN26_RR_VISUAL_MS_360_5060.tif
Size is 20779, 46754
Coordinate System is:
PROJCRS["WGS 84 / UTM zone 59S",
    BASEGEOGCRS["WGS 84",
        DATUM["World Geodetic System 1984",
            ELLIPSOID["WGS 84",6378137,298.257223563,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4326]],
    CONVERSION["UTM zone 59S",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",171,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",0.9996,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",500000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",10000000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["easting",east,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["northing",north,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    ID["EPSG",32759]]
Data axis to CRS axis mapping: 1,2
Origin = (353999.799999999988358,5068000.629999999888241)
Pixel Size = (0.770000000000000,-0.770000000000000)
Corner Coordinates:
Upper Left  (  353999.800, 5068000.630) (169d 9'45.50"E, 44d31'35.55"S)
Lower Left  (  353999.800, 5032000.050) (169d 9' 8.52"E, 44d51' 1.68"S)
Upper Right (  369999.630, 5068000.630) (169d21'50.06"E, 44d31'46.58"S)
Lower Right (  369999.630, 5032000.050) (169d21'17.12"E, 44d51'12.83"S)
Center      (  361999.715, 5050000.340) (169d15'30.36"E, 44d41'24.33"S)
Band 1 Block=128x128 Type=Byte, ColorInterp=Red
  NoData Value=0
Band 2 Block=128x128 Type=Byte, ColorInterp=Green
  NoData Value=0
Band 3 Block=128x128 Type=Byte, ColorInterp=Blue
  NoData Value=0
Band 4 Block=128x128 Type=Byte, ColorInterp=Undefined
  NoData Value=0

And gdalinfo output for one of the underlying rasters:

gdalinfo 20240602_230818_SN26_RR_VISUAL_MS_360_5040.tif
Driver: GTiff/GeoTIFF
Files: 20240602_230818_SN26_RR_VISUAL_MS_360_5040.tif
Size is 10390, 25974
Coordinate System is:
PROJCRS["WGS 84 / UTM zone 59S",
    BASEGEOGCRS["WGS 84",
        DATUM["World Geodetic System 1984",
            ELLIPSOID["WGS 84",6378137,298.257223563,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4326]],
    CONVERSION["UTM zone 59S",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",171,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",0.9996,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",500000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",10000000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Engineering survey, topographic mapping."],
        AREA["Between 168°E and 174°E, southern hemisphere between 80°S and
equator, onshore and offshore. New Zealand."],
        BBOX[-80,168,0,174]],
    ID["EPSG",32759]]
Data axis to CRS axis mapping: 1,2
Origin = (359999.640000000013970,5060000.330000000074506)
Pixel Size = (0.770000000000000,-0.770000000000000)
Metadata:
  AREA_OR_POINT=Area
Image Structure Metadata:
  COMPRESSION=LZW
  INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  (  359999.640, 5060000.330) (169d14' 9.36"E, 44d35'59.00"S)
Lower Left  (  359999.640, 5040000.350) (169d13'49.66"E, 44d46'46.86"S)
Upper Right (  367999.940, 5060000.330) (169d20'12.11"E, 44d36' 4.44"S)
Lower Right (  367999.940, 5040000.350) (169d19'53.53"E, 44d46'52.34"S)
Center      (  363999.790, 5050000.340) (169d17' 1.19"E, 44d41'25.70"S)
Band 1 Block=256x256 Type=Byte, ColorInterp=Red
  NoData Value=0
Band 2 Block=256x256 Type=Byte, ColorInterp=Green
  NoData Value=0
Band 3 Block=256x256 Type=Byte, ColorInterp=Blue
  NoData Value=0
Band 4 Block=256x256 Type=Byte, ColorInterp=Undefined
  NoData Value=0

What could be the reason for such a significant difference?
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