Hey all, in trying to build a map from scratch I've run into a number of questions.
*) The Iresolve (and friends) mechanism seems to be based on the extensive use of URL/URI. e.g. the URL in the constructor of the MemoryServiceImpl(). I can see that it's value is http://localhost/scratch/ but what is this supposed to be? Does each 'resolveable' instance get its own URL so that the whole system is dependent on programmer's tracking these URLs? The explanation currently has a bunch of references to how Eclipse does things without any link to the docs where that is explained. Some extra links or documentation is needed to explain the idea and the relevance of the URL in the resolve system. *) What are the differences between IService and IGeoResource? From the recent doc, I see there's a split between the two but I don't understand the relevance of the split. IService appears to be more generic and useable for information whereas IGeoResource must be used for actual geographic data. Is that the right idea? *) What's the terminological difference between a Coordinate Reference System (CRS) and a Spatial Reference System (SRS)? While the use of all these terms around the web is generally sloppy I have not yet been able to figure out a reasonable distinction between these two ideas. *) What elements in the data stack have their own CRS info? A displayed map must have its own CRS with all input layers transformed to that when added. Presumably, by default, the map uses a CRS of one of the initial layers added when crated but it must also be possible to create a map with a programmer defined CRS. In the layer stack, where does the feature's CRS get stored? As one of the attributes of Feature? As one of the Attribute of FeatureType? While I can now create a layer from scratch, I've not yet figured out where to add the CRS in the construction process. Are there other CRS's stored? What docs explain this stuff? Thanks for any answers/pointers, adrian _______________________________________________ User-friendly Desktop Internet GIS (uDig) http://udig.refractions.net http://lists.refractions.net/mailman/listinfo/udig-devel
