GeoTIFF metadata lost when splitting a GeoTIFF up into tiles

[marklit]

ImageMagick version

7.1.1-21

Operating system

Linux

Operating system, version and so on

Ubuntu for Windows (Ubuntu 20 effectively)

Description

The GeoTIFF information on the location an image was taken in, its projection, etc.. isn't retained / recalculated when a large GeoTIFF is broken up into tiles.

Steps to Reproduce

$ git clone https://github.com/ImageMagick/ImageMagick
$ cd ImageMagick
$ mkdir -p build
$ ./configure --prefix=`pwd`/build
$ make -j$(nproc)
$ sudo make install

$ wget -c https://maxar-opendata.s3.amazonaws.com/events/New-Zealand-Flooding23/ard/60/213311212331/2022-11-01/104001007C86B200-visual.tif
$ gdalinfo 104001007C86B200-visual.tif

Driver: GTiff/GeoTIFF
Files: /mnt/f/gis/Global/maxar-open-data/104001007C86B200-visual.tif
Size is 17408, 17408
Coordinate System is:
PROJCRS["WGS 84 / UTM zone 60S",
    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]],
...

$ build/bin/convert \
    104001007C86B200-visual.tif \
    +repage \
    -crop \
    512x512 \
    104001007C86B200-%04d.tiff
$ gdalinfo 104001007C86B200-0000.tiff

Driver: GTiff/GeoTIFF
Files: /mnt/f/gis/Global/maxar-open-data/104001007C86B200-0000.tiff
Size is 512, 512
Image Structure Metadata:
  INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,  512.0)
Upper Right (  512.0,    0.0)
Lower Right (  512.0,  512.0)
Center      (  256.0,  256.0)
Band 1 Block=512x5 Type=Byte, ColorInterp=Red
Band 2 Block=512x5 Type=Byte, ColorInterp=Green
Band 3 Block=512x5 Type=Byte, ColorInterp=Blue

Images

https://maxar-opendata.s3.amazonaws.com/events/New-Zealand-Flooding23/ard/60/213311212331/2022-11-01/104001007C86B200-visual.tif

[snibgo]

I suggest using magick instead of convert.

Your tiff file contains 14 images. If you want to process just the first, use a [0] suffix.

No, IM does not copy all the metatdata from the input to the output. You can use exiftool for that, like this:

magick 104001007C86B200-visual.tif[0] x.tiff

exiftool -tagsFromFile 104001007C86B200-visual.tif x.tiff

[marklit]

Copying the metadata wholesale wouldn't be accurate. Each image is offset from the original file's offset.

[snibgo]

In that case, a script could adjust the offsets as required.

[fmw42]

Or use EXIFTOOL to copy just the GEOTIFF data