Martin, One follow-up question, when is the target release date of SIS 1.5 which includes the COG writer? Sedona really needs a pure Java COG writer without GDAL.
Thanks, Jia On Wed, Nov 8, 2023 at 11:38 PM Jia Yu <ji...@apache.org> wrote: > > Hi Martin, > > This is great work! Looking forward to the SIS 1.5 release! > > Thanks, > Jia > > On Wed, Nov 8, 2023 at 11:28 PM Bertil Chapuis <bchap...@gmail.com> wrote: > > > > Really interesting benchmark, thank you. > > > > > On 8 Nov 2023, at 23:04, Martin Desruisseaux > > > <martin.desruisse...@geomatys.com> wrote: > > > > > > Hello all > > > > > > Apache SIS 1.4 contains a Cloud Optimized GeoTIFF reader, and a GeoTIFF > > > writer is currently available in 1.5-SNAPSHOT (not yet fully completed). > > > Those reader/writer are in pure Java (ignoring native code provided by > > > the JDK itself). There is a widespread belief that a Java code would > > > surely be slower than C/C++ code. To verify, we conducted a superficial > > > benchmark. It is very superficial in that we tested only one image with > > > one compression method, no sub-region, no subsampling, no > > > parallelization, no reprojection, etc. But the results nevertheless > > > question the above-cited belief. In that benchmark, Apache SIS and GDAL > > > performances were equivalent. The numbers actually report Apache SIS as > > > very slightly faster than GDAL, but we cannot conclude much because of > > > all above-cited limitations, because there is a possibility of biais in > > > time measurements (we tried to compensate it), because the differences > > > are close to margin errors, and because Apache SIS spent 95% of its time > > > in the native code of the `java.util.zip` package. Assuming that GDAL > > > also uses the `zlib` library (we did not tested with `libdeflate`), 95% > > > of this benchmark is actually measuring the same code. However for the > > > remaining 5%, it suggests that the interfacing between Java and the > > > native code in `java.nio` and `java.util.zip` packages can be as > > > efficient as the interfacing between a C/C++ application and native > > > libraries. > > > > > > More details are there: > > > https://www.geomatys.com/2023/10/05/geotiff-reader-writer-performance-comparison/ > > > > > > Martin > > > > > > > >
