[ka-Map-users] Function to clear addObjectGeo
Brent Pedersen
bpederse at gmail.com
Wed Mar 22 10:42:25 EST 2006
i only used this funciton because i didn't notice you could accomplish the
same (over all canvases) by sending no args to removeObject. a simple change
would be to allow the second arg to the existing removeObject() specify a
canvas....
-b
On 3/22/06, Paul Spencer <pspencer at dmsolutions.ca> wrote:
>
> not sure if I commented on this before, but it should be noted that a
> function like this already exists (removeObject) but it doesn't allow
> you to clear all the overlays on a single canvas, it only allows
> removing individual overlays or all overlays.
>
> Is there interest in adding this function? I don't see a need for it
> as I usually manage the overlays separately from kaMap and thus have
> have a reference to the things that need to be removed.
>
> Cheers
>
> Paul
>
> On 5-Mar-06, at 12:56 PM, Brent Pedersen wrote:
>
> > hi chris, another utility function you'll use:
> >
> > kaMap.prototype.removeOverlays = function(canvas){
> > len = this.aObjects.length;
> > for(i=0;i
> > var item = this.aObjects[i];
> > if(item.canvas == canvas){
> > canvas.removeChild(item);
> > item.canvas = null;
> > item = null;
> > this.aObjects.splice(i--,1);
> > len = this.aObjects.length;
> > }
> > }
> > }
> >
> > then call myKaMap.removeOverlays(myCanvas) at the start of
> > drawMarkers. because otehrwise, you jsut keep adding new markers
> > without getting rid of the old ones. and it will get rid of them
> > when you're not at the scale you want.
> >
> > also as you have it now, you're creating a new canvas every time
> > drawMarkers is called. probably bad.
> >
> > i'm not sure about the memory leakage of any of this...
> > -b
> >
> >
> >
> >
> > On 3/5/06, Base Bloc < chris at basebloc.com> wrote:
> > Hi Guys,
> >
> >
> > I'm still plugging away to get some workable functions together to
> > draw markers with tool-tips and it's hard work as I'm experienced
> > with PHP but not so hot on JavaScript and DOM so am making all the
> > usual mistakes but getting there slowly. I now have a system in
> > place that at a curtain scale places markers within an extended
> > extent of the visible map tiles using HttpRequest. All is working
> > fine and I currently have the system getting markers from a
> > database to place markers on the map at the required scale
> > (1:300000), then adding more markers as the map is panned.
> >
> >
> > The problem I'm encountering now is that although the function is
> > working correctly as in it won't add markers+tool-tips until the
> > map is zoomed to 1:300000 when the map is zoomed back out above
> > 1:300000 the markers previously called all remain on screen and as
> > there are over 7000 points you can imagine what this looks like at
> > 1:4000000.
> >
> >
> > Is there a simple way to clear all of the markers created by
> > addObjectGeo when the map is zoomed out past a curtain scale or
> > better yet add an event related to myKaMap.getCurrentScale() so
> > they are only displayed when the scale in greater than X?
> >
> >
> > Here are the functions I'm using at present:
> >
> >
> > //creates separate image for each marker
> >
> > function create_marker (img_id, var_1, lat, lon)
> >
> > {
> >
> >
> > document[img_id] = document.createElement( 'img' );
> >
> > document[img_id].src = 'images/kamap.gif';
> >
> >
> > var bname = navigator.appName;
> >
> > if (bname == "Microsoft Internet Explorer")
> >
> > {
> >
> > document[img_id].attachEvent
> > ("onmouseover",tool_tip)
> >
> > document[img_id].attachEvent
> > ("onmouseout",tool_tip_out)
> >
> > document[img_id].attachEvent
> > ("onclick",page_link)
> >
> > }
> >
> > else
> >
> > {
> >
> > document[img_id].addEventListener
> > ("mouseover",tool_tip,false)
> >
> > document[img_id].addEventListener
> > ("mouseout",tool_tip_out,false)
> >
> > document[img_id].addEventListener
> > ("click",page_link,false)
> >
> > }
> >
> >
> > //Sends content and format
> > options to tool-tip
> >
> > function tool_tip(){
> >
> >
> > var test_var = var_1;
> >
> > var text = "My name
> > is " +test_var+ ", and I'm am now understanding JavaScripts";
> >
> > overlib(text,
> > STICKY, MOUSEOFF, CAPTION, 'info')
> >
> > }
> >
> >
> > myKaMap.addObjectGeo( myCanvas, lat, lon, document[img_id] );
> >
> >
> > }
> >
> >
> > function drawMarkers(){
> >
> > Big_Extents = myKaMap.getGeoExpandedExtents();
> >
> > myCanvas = myKaMap.createDrawingCanvas( 5000 );
> >
> >
> > //draw Markers within Big_Extents using kaXMLOverlay or just
> > addObjectGeo()
> >
> >
> > var scale = myKaMap.getCurrentScale();
> >
> >
> > if (scale <= 200000)
> >
> > {
> >
> >
> > //this is where the HttpRequest would normally go, but
> > I have placed a couple of sample markers to make the script more clear
> >
> > create_marker('C02573', 'Box', 511275, 1363860);
> >
> > create_marker('C02574', 'Pipe', 515736, 1364260);
> >
> >
> > }
> >
> >
> > }
> >
> >
> > var scale = myKaMap.getCurrentScale();
> >
> >
> >
> > myKaMap.registerForEvent( KAMAP_SCALE_CHANGED, null,
> > drawMarkers );
> >
> > myKaMap.registerForEvent( KAMAP_EXTENTS_CHANGED, null,
> > maybeRedraw );
> >
> > myKaMap.registerForEvent( KAMAP_MAP_INITIALIZED, null,
> > drawMarkers );
> >
> >
> > }
> >
> >
> > Sorry there are a few calls to functions there which I have not
> > added above, I didn't want to do a 500 line cut and paste, once I
> > have it working properly I will post the full code and related
> > functions.
> >
> >
> > Any suggestions on a fix to this problem would be appreciated.
> >
> >
> > Thanks,
> >
> >
> > Chris
> >
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > Christopher Brown
> >
> > Head of Internet Development
> >
> > Base Bloc Cambodia
> >
> > #33, 123, Phnom Penh, Cambodia.
> >
> > P.O. Box 2086
> >
> > www.basebloc.com
> >
> > Tel (+885) 12 315 302
> >
> >
> >
> > _______________________________________________
> > ka-Map-users mailing list
> > ka-Map-users at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/ka-map-users
> >
> >
> >
> > _______________________________________________
> > ka-Map-users mailing list
> > ka-Map-users at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/ka-map-users
>
> +-----------------------------------------------------------------+
> |Paul Spencer pspencer at dmsolutions.ca |
> +-----------------------------------------------------------------+
> |Applications & Software Development |
> |DM Solutions Group Inc http://www.dmsolutions.ca/|
> +-----------------------------------------------------------------+
>
>
>
>
>
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