On 7/12/10 4:48 AM, Andreas Hocevar wrote: > On Jul 12, 2010, at 06:45 , Gabriel Roldan wrote: > >> On 7/9/10 5:25 PM, Andreas Hocevar wrote: >>> Hi, >>> >>> just a quick note to let you know that proj4js can do lazy >>> loading of crs definitions. >>> >>> But I doubt that we will be using projections other than 900913 >>> in the map viewers, because 900913 is our only option if we want >>> to use Google layers (and OSM if we don't want to provide our own >>> tileset). >> But there may be the case that the user doesn't care about google >> layers nor OSM ones, he just want to use data from his >> municipality's WMS, but the WMS doesn't support 900913. If GeoNode >> doesn't support the CRS the data is published in, then he can't use >> the data at all. Then GeoNode is useless. > > Good point. Tim and I have been talking about some kind of "CRS > negotiation", meaning the client has to figure out the common > denominator of available CRS of all layers added to a map, and warn > about layers that have to be removed because they don't match the CRS > of other layers. > >> That's exactly what happened to me and why I opened that ticket. >> >> Aside: the whole question arises from the fact that we're storing >> the center point of the map in 4326, then who performs the >> transformation to Map's CRS. Wouldn't make more sense to store the >> map's center point in the Map's CRS to start with? (I don't know >> about the internals of this design decision so excuse me if I'm >> missing something obvious.) > > I was thinking along the same lines when I wrote my initial reply, > but considered the fact that the coordinates are stored in 4326 as > engraved in stone. But you are right, as long as we don't search maps > (only layers) by location, storing the map bounds/center in map CRS > coordinates would solve the problem, and make map persistence 100% > compatible with the gxp viewer. that would be (_IMHO_) step in doing it the right way. And it doesn't preclude the ability to make map searches by map bounds in the future, if we need to. There may be a couple options: - A Map may have it's own metadata record, where lat lon bounds is already there to be used on spatial searches - we may have our own database of maps, where we could search by something like toWGS84(mapbounds) overlaps my bounds.
Gabriel > > -Andreas. -- Gabriel Roldan OpenGeo - http://opengeo.org Expert service straight from the developers.
