Thanks for the info and links. Just the thing i was thinking of. Because of the huge amount of (eventually) data points i think i try the 'chatty' version first. Still tinkering with OpenLayers and changing projection though.
Regards Heiko Am 3.4.2009 schrieb "Steve Lime" <steve.l...@dnr.state.mn.us>: >To do this you need some sort of an observer for the map and an image >map is >one way to do that. Here's an example: > > http://www.dnr.state.mn.us/ice_out/index.html > >In this case the data to be displayed are encoded in the image map >produced >by MapServer (I used the template mechanism). So, onMouseOver, a >function >is called to display the data object. You could just as easily wrap an >ajax call >in that function. You'd need to store a unique ID as part of your image >map >sufficient so that you can query postgres. Then the function is called >you >pass the ID and then use that to retrieve the additional data. > >The image map will work when you have a relatively small number of >reasonably >spaced features AND you're interface is not particularly interactive. I >don't >think it's possible to combine an image map with your typical pan/zoom >operation. > >Another solution is create a polling capability in your application and >tie it to >some sort of an event, such has pausing the mouse for a few seconds. If >that >event happens you do a spatial query to see if the user is hovering over >anything >and if so you do something. Here's an example site: > > http://www.dnr.state.mn.us/waters/csg/index.html > >If you hold your mouse over one of the points on the map you'll get >details about >that feature. At each pause a query is done behind the scenes and if >something >is found a popup is populated. It's kinda chatty but works. Watch the >above page >in FireBug so see the network communication. OpenLayers has a great >hover control >to do this sort of thing. You can also use click events, like so: > > http://www.dnr.state.mn.us/waters/csg/index_copy.html > >Creating the content to send back will depend on the data. In the above >cases I use >MapServer templates to build it. You could use your favorite scripting >language to do >so as well. > >Hope this helps! > >Steve > >>>> Heiko Schröter <schro...@iup.physik.uni-bremen.de> 04/02/09 7:44 AM >>>> >Hello all, > >we are displaying satellite measurement geolocations with Mapserver and >PostGIS/Postgres underneath. > >I would like to add a feature (similar to the MapServer:ImagMap stuff) >that >displays some more info about the point on which the mouse is over >inside the >map. i.e. geolocation, name of datafile, value or so. These infos can be > >sourced from the Postgres db. It is ok to just show these infos on the >bottom >window frame (like the MapServer:ImageMap example). > >How do i create the html code (javascript or php or whatever needed) >with the >dynamic content piped back from the Postgres db ? >Sorry if this is an obvious question. I did read the ImageMap and >Template >stuff, but i cannot get grip to the logic when the data are coming from >a db. > >Any pointer to more info or background knowledge deeply apreciated. > >Thanks. >Heiko > > >_______________________________________________ >mapserver-users mailing list >mapserver-users@lists.osgeo.org >http://lists.osgeo.org/mailman/listinfo/mapserver-users > _______________________________________________ mapserver-users mailing list mapserver-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapserver-users