They could do like your second deduction. use KMLs that only load data for the current viewpoint. Send the current bounds to the server, which then returns the required data. If map moves, make a new request.
But in their case they appear to use a more complicated system I dont know if you know, but GMaps uses 'tiles' for the map imagery. the mapping is broken into precomputed tiles. They use a similar system, loading a .json file per tile. These could be precomputed, or a dynamic script, could work out the bounds of the tile, and return the relevent features. ... it all depends on how much data you have to display, or what sort of responsitiveness you want. The geocaching system is possibly close to optimal. But a lot or work to setup. Alternativly if you have less than 100,000 points to map, might like Google Fusion tables :) On Tue, Jul 26, 2011 at 5:21 PM, amnesia7 <col.gib...@gmail.com> wrote: > Can anyone explain how the new beta geocaching site might have managed > to get all those markers displayed? > > http://www.geocaching.com/map/beta/ > > I assume they're using a kml file merged into maps by Google some how > but isn't there a 3Mb limit on the zipped kml or 10Mb limit on the > unzipped version? Wouldn't the number of geocaches all over the world > blow that limit when they zoom out to show full map? > > Would they be limiting the number of entries that are actually > displayed when zoomed out somehow (server-side?) since when zoomed out > there could actually be quite a few entries within the same area of > the map covered by the icon itself? > > There are probably other maps that have the same issue of displaying > millions of entries that goes beyond the kml filesize limit but this > was the example I found and was wondering how they could do that since > I have a lot of markers to display and was interested to know how this > had been achieved. > > Thanks > > -- > You received this message because you are subscribed to the Google Groups > "Google Maps JavaScript API v3" group. > To post to this group, send email to google-maps-js-api-v3@googlegroups.com. > To unsubscribe from this group, send email to > google-maps-js-api-v3+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/google-maps-js-api-v3?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google Maps JavaScript API v3" group. To post to this group, send email to google-maps-js-api-v3@googlegroups.com. To unsubscribe from this group, send email to google-maps-js-api-v3+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-maps-js-api-v3?hl=en.
