[OpenLayers-Users] Looping through unique markers?

Fri Feb 27 16:20:53 EST 2009

OK,  thanks to help from Chris....and studying the marker/event related code
over at openflights.org, I've managed to get my map to display in Firefox,
plus I've got my marker-specific pop-ups generating.

And yes, Firefox draws the points and zooms a heckuva lot faster!
So, the copy OUTSIDE of our corporate network is working the way I want it
to.

But when I try to pull up an identical copy saved to a webserver that's
WITHIN our corporate network, Firefox seems to be attempting to load the
page forever (white page). Firebug (which I really don't know how to use)
points to what is apparently line 224 in OpenLayers.js.

It does this whether I point this to the OpenLayers.js file over at the
OpenLayers site...or if I point it to a copy of that file as saved within
its own directory.

Line 224:
var factory=null;if(typeof GearsFactory!='undefined'){factory=new
GearsFactory();}else{try{factory=new
ActiveXObject('Gears.Factory');if(factory.getBuildInfo().indexOf('ie_mobile'
)!=-1){factory.privateSetGlobalObject(this);}}catch(e){if((typeof
navigator.mimeTypes!='undefined')&&navigator.mimeTypes["application/x-google
gears"]){factory=document.createElement("object");factory.style.display="non
e";factory.width=0;factory.height=0;factory.type="application/x-googlegears"
;document.documentElement.appendChild(factory);}}}

I don't suppose anybody might have a clue why this is doing this?

Thanks!

-= Dave =-

-----Original Message-----
From: Heidt, Christopher M. [mailto:CHRISTOPHER.M.HEIDT at saic.com] 
Sent: Friday, February 27, 2009 12:22 PM
To: David Raasch; users at openlayers.org
Subject: RE: [OpenLayers-Users] Looping through unique markers?

Every browser cept ie7 is throwing "XMLHttpRequest.create is not function"
-----Original Message-----
From: users-bounces at openlayers.org [mailto:users-bounces at openlayers.org]
On Behalf Of David Raasch
Sent: Friday, February 27, 2009 12:35 PM
To: users at openlayers.org
Subject: Re: [OpenLayers-Users] Looping through unique markers?

OK, I discovered where apparently, this is known to happen when using Vector
layers.  And I had forgotten to comment-out my Vector layer completely when
switching over to using a Marker layer instead.  So, I've got that part of
it solved.

That leaves me with:

1) How to get each marker to have its own unique function? ( I know right
now it's just an "alert", but I plan on making that function trigger a
pop-up with some marker-specific HTML code in it in the near future).
2) Why do none of the markers (or the circle, for that matter) display in
Firefox?

Thanks!

-= Dave =-

-----Original Message-----
From: users-bounces at openlayers.org [mailto:users-bounces at openlayers.org]
On Behalf Of David Raasch
Sent: Friday, February 27, 2009 10:44 AM
To: users at openlayers.org
Subject: Re: [OpenLayers-Users] Looping through unique markers?

Hmmm... I just realized that if I go to the map controls and turn off the
circle and vector layers, then the events work for all icons, in the sense
that they all activate an "alert" pop-up.  Of course, the trouble is, all
alerts say exactly the same thing, basically showing the text for point #571
only.

So, it looks like I've got two problems:  Why is it that the Vector and
Circle layers seem to be "interfering" with the click events?  And
apparently I have to figure out how to give each registered event instance a
reference to its own unique "evt" function.

-= Dave =-

-----Original Message-----
From: users-bounces at openlayers.org [mailto:users-bounces at openlayers.org]
On Behalf Of David Raasch
Sent: Friday, February 27, 2009 8:13 AM
To: users at openlayers.org
Subject: [OpenLayers-Users] Looping through unique markers?

Greetings All!

When I posted to the list last week, I had coded my little app to use
FEATURES to draw marker icons and rig-up word-balloon pop-ups whenever they
were clicked-on.

However, the markers took a very, very long time to load.  So, digging
further into the archives of this discussion list, I discovered that,
although using MARKERS to draw marker icons is considered to be "the old way
of doing it", that way is apparently faster.

So, I set about commenting-out the feature-adding/drawing lines in my code
and inserting some lines that would loop through my array of data, draw each
marker, and register an event for that marker.

My problem is that I'm only getting the event to work on the FINAL marker in
the array.

I've posted my files here:

http://www.davidraasch.com/ww/map_v4.html

If you zoom in over that cluster near Chicago and click, eventually you'll
trigger an alert message on the one marker, which is the last one in the
array.  It will say "You clicked on marker m571".

Feel free to do a "view source", but here are the pertinent lines from my
code:

var markers_layer = new OpenLayers.Layer.Markers( "Markers Layer");
map.addLayer(markers_layer);

	var xml_points =
xmlDoc.documentElement.getElementsByTagName("point");
		  		var m = [];
		  		for (var i = 0; i < xml_points.length;
i++) {
		         		var type =
xml_points[i].getAttribute("type");
		    	 	 	var thislat =
(parseFloat(xml_points[i].getAttribute("lat")));
	    		  		var thislng =
(parseFloat(xml_points[i].getAttribute("lng")));
	    		  		var html =
xml_points[i].getAttribute("html");

{to reduce "noise" here for you, I'm leaving out the if-then statements that
determine which exact icon graphic file to use, plus its height and width }

	// Code to push each point as a MARKER LAYER MARKER

					var size = new
OpenLayers.Size(icon_width,icon_height);
            			var offset = 0; // new
OpenLayers.Pixel(-(icon_width/2), -icon_height);
            			var icon = new
OpenLayers.Icon(icon_image,size,offset);

            			 m[i] = new OpenLayers.Marker((new
OpenLayers.LonLat(thislng,thislat).transform(new
OpenLayers.Projection("EPSG:4326"), map.getProjectionObject())),icon);
            			 markers_layer.addMarker(m[i]);
   		  			 m[i].events.register ('click',
m[i], function(evt) {alert ('You clicked on marker m'+ i);
OpenLayers.Event.stop (evt); })

           				// alert("i="+ i);
				} // end of "for i = 0  to all POINTS

(Originally, I was using just the variable "m1" to represent the markers, as
taken from an example I found somewhere on the openlayers.org site.  But
then, in debugging it, I switched to using "m"
as an array, just to make sure I did understand what we're trying to do
here.)

I should also mention that, for some reason, the markers don't even appear
to load in Firefox!  I can only see them in IE.  ????

Any thoughts?

Thanks!

-= Dave =-

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