Thanks for these links, Martin. Cheers, Chris
On Jul 30, 2012, at 4:43 PM, Martin Desruisseaux wrote: > Hello Adam > > Le 31/07/12 01:20, Adam Estrada a écrit : >> Where in your code is the geometry support? I need a heads up on where to >> find it. > > In the "pending" source code repository of Geotk, directory modules/geometry. > However this particular topic is still work in progress, both on our side and > on OGC side, and deserve a bit of context: > > Geometries are defined by the ISO 19107 international standard, which is > reputed complex. Indeed, I'm not aware of any open source library > implementing fully this standard. Most projects use the simpler Java Topology > Suite (JTS) library. However JTS is designed for two-dimensional geometries > in a Cartesian space (JTS can store a 'z' ordinate value, but doesn't use > it). By contrast, ISO 19107 is designed for 1D, 2D and 3D geometries in > arbitrary coordinate systems. > > In 2007, a Ph.D. student published his thesis on an implementation of ISO > 19107 geometries (http://w1.cirrelt.ca/~jena/files/DiplThesisJena07.pdf). In > our company, we also supported a Ph.D. student who finished his thesis last > year. We are considering to support yet an other Ph.D. student on this topic > - this is to say that this particular topic is difficult. The ISO 19107 > editor is aware of those kind of difficulties and is in the process of > revising the ISO 19107 standard at OGC. > > In the main time, we are using a mixed approach: we use the ISO 19107 Java > interfaces in some code, but the JTS library as the underlying > implementation. So the "geometry" group of modules contains a module that > provide a partial ISO 19107 implementation as wrappers around JTS > implementation. This has the JTS limits (2D, Cartesian), but may be the most > functional implementation for now... > > Martin > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Chris Mattmann, Ph.D. Senior Computer Scientist NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA Office: 171-266B, Mailstop: 171-246 Email: [email protected] WWW: http://sunset.usc.edu/~mattmann/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Adjunct Assistant Professor, Computer Science Department University of Southern California, Los Angeles, CA 90089 USA ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
