Hello all
There is a note about current development going on the JDK8 branch of
Apache SIS:
Two new map projections has been added: Lambert Cylindrical Equal Area
and Albers Equal Area. I hope to add another projection (Lambert
Azimuthal Equal Area) next week. Those projections were added for as a
more convenient way to compute the surface of polygons.
Started the port of some GeoTIFF code. The intend is to allow Hao (from
Google Summer of Code) to start working on GeoTIFF metadata soon. She
worked on Landsat and Modis last months because it was easier than
GeoTIFF, but it seems a good time now for moving on the GeoTIFF ones.
Note: prior Java 9, TIFF reader was available in Java Advanced Imaging
(JAI) extension. Unfortunately JAI has not been maintained any more for
years. Geotk was using JAI, but given JAI current situation one of
Apache SIS goals is to avoid that dependency. A "hidden" TIFF reader was
also available in standard JDK. That strange (I presume not officially
supported) reader is initially not reported among the supported format,
but appears "magically" after we perform some AWT operations like
showing a Swing window. In Java 9, Oracle will port the JAI's TIFF
reader to the JDK.
At first we used the JAI's TIFF reader and also tried some other readers
available in other projects, but we progressively came to write for
various reasons: better controls on the way we create metadata from the
TIFF tags, performance (especially when performing random accesses in
uncompressed TIFF files), leverage more the tiling capabilities of TIFF
files in the context of image pyramids, support some unusual variants
that we have seen and which - while legal - were not supported in most
other libraries.
The GeoTIFF work is just starting. It will probably take months to
complete, in parallel with other work that need to continue (NetCDF,
referencing, GML, etc.). Like usual, we take this port as an opportunity
for revisiting some design choices.
Martin
