Hello all
In August 17th 2017, we presented an introduction to Apache Spatial
Information System (SIS) in the Free and Open Source Software for
Geospatial (FOSS4G) conference. Discussions about performance and
accuracy were planed, but skipped because of lack of time. We put the
intended content in a series of 2 blog posts. The first post, about
performance, is available at [1]. The key findings are:
* Proj.4 is generally faster than Apache SIS on Java 8. The identified
cause is the cost of trigonometric functions.
* Some (but not all) trigonometric functions are much faster in Java
9, but we have not yet benchmarked SIS on Java 9.
* Despite the above, Apache SIS is sometime faster than Proj.4 (400
times faster in an extreme case). This can be explained by
mathematical work done in SIS.
* Numerical results are in close agreement for map projections, but
can differ by 1 or 2 metres for datum shifts. This is because of
different ways to use the EPSG geodetic dataset ("early-binding"
versus "late-binding" approaches).
More details are given at [1]. A second blog focussed on the accuracy
topic will be posted later.
Martin
[1]
https://www.geomatys.com/wordpress/index.php/2017/08/28/english-proj-4-versus-apache-sis-a-performance-comparison/?lang=en
