Adrian Custer wrote on 01/14/2006 02:31:27 AM:
> 1) can we actually read the spec or is it private? If we can read > it, could you post a link to it? Right now, it's public and published. Anyone with 130(ish) US Dollars burning a hole in their pocket may buy it, but may not post it on their website. It is, however, marked for adoption on the OGC website as a replacement for Topic 6 of the Abstract Specification. At that point "some version" of the document which is not too different than the final specification will be made available for free from the OGC website. But who knows how long it will take for this adoption process to happen. > 2) what do you mean when you saya the following? > "But try to imagine the significance of a polygon defined using a > CRS with one spatial axis and one temporal axis, or a sphere defined > with two spatial dimensions and one temporal dimension. While these > constructs may have some esoteric use in the halls of mathematicians > and those studying Einstein's theory of relativity, spatio-temporal > polygon and spheres are not useful map concepts." > > For a historical gis, we certainly do need polygons which have > different shapes, topologies, presence in space-time. "The roman > empire" has a very different presence on a map according to what > part of the historical record you consider. Neither the map at any > particular time, nor the map of the "maximal extent" (which may have > occurred in different parts of the world during different centuries) > are particularly useful. So if we want geoapi to provide the tools > for historical gis, then we need either to have coverageTimeSeries > or have coverages with temporal objects within. But perhaps I have > misunderstood you; I would love to read the spec. My intent was not to say that temporal information is useless. Temporal information is covered via the "temporalElement" role of the domain object. When specified separately as a temporal element, I believe it plays the role you want it to play (e.g., the _entire_ polygon exists during this period of time). My objection is to the mistaken application of a temporal axis to spatial geometry. If a polygon has one spatial axis and one temporal axis (and doesn't recognize the difference), then the coordinates of each vertex don't make much sense. Spatially speaking, you don't have _any_ polygons, much less a whole set of them which are valid at different times. Bryce ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642 _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
