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