[EMAIL PROTECTED] wrote on 08/09/2006 06:37:25 AM:
> Hey all, perhaps especially Martin, > > > In looking at the code of the interface > > http://geoapi.sourceforge. > net/snapshot/javadoc/org/opengis/referencing/cs/SphericalCS.html > and perhaps this is the current form: > http://svn.sourceforge. > net/viewvc/geoapi/trunk/geoapi/src/main/java/org/opengis/referencing/cs/SphericalCS. > java?view=markup > > It's just a shell. There is nothing there preventing the interface from > being an 'degenerate ellipsoidal' crs. > > 1) How does this shell imply that implementations shall be classes like > geotools' DefaultSphericalCS? Is this simply a request that implementors > not create derivatives with the distance axis a height_above_ellipsoid? > (This question is about how geoapi works not about what a sphericalCS is > supposed to be---I get what is implied mathematically but not how geoapi > expresses this expectations of others.) ISO 19111 says this is a 3D coordinate system (always). {Radius, angle, angle} A 3D degenerate ellipsoidal CS is {ellipsoidal height, angle, angle}. The average error you would get by confusing GeocentricCRS/SphericalCS with GeographicCRS/EllipsoidalCS is 6000km (give or take). :) Zero does not mean sea level. :) > > 2) Could this interface be implemented by a PolarSphericalCS? That is > substituting a \Phi coordinate (angle from the rotation axis) for the > \Psi coordinate (angle away from equator). Would such an implementation > go against the intent of the interface? We either need to note the > distinction in both the geoapi javadoc and the geotools javadoc, or we > need to change the geotools javadoc to state that it has chosen to > implement *not* a polarSpherical but a ??Spherical coordinate system. Yes, by reason of that's what it's supposed to be. :) This can be used in conjunction with a GeocentricCRS. Want to model radar or do photogrammetry? Use an EngineeringCRS with a SphericalCS, in which case, \phi is angle from zenith or nadir. In general, the CS interfaces _are_ shells. Implementations (with code) must ensure that the UsesAxes associations obey the constraints of the standard. This is too convoluted to enforce with interfaces, I think. Bryce ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
