[OpenLayers-Users] externalGraphic rotation in a vector layer

[Chander Ganesan]

Andreas Hocevar wrote:
 > your code does not seem correct. At the time you request the extent,
 > there is no extent yet. And you do not add the feature to the layer.
 > The following code works for me (tested on FF2, IE6, IE7, Opera9 and
 > Safari3 with both png and gif images):

Thanks!  I had copied the code below from a much larger script, and
apparently copied the order of different components wrong (hence the
errors you noticed).

It turns out, I had applied the patch against the 2.6 release, and not
against trunk.  As a result it didn't work.  Once I reapplied against
trunk it worked like a charm...

I'm actually wondering if my little demo might be a good thing for the
gallery...

It's here:

http://www.otg-nc.com/csc/index1.html   -- This one draws planes and
"moves" them over time across the base layer.  This requires the patch...

And another one that might be a good demo is:

http://www.otg-nc.com/csc/index.html  -- This one takes
5,10,15,20,25,30,35,40, and 45 minute NEXRAD weather imagery (over the
US) and cycles through the layers to give the impression of a "moving
weather" map.  This works with OL 2.6 .

However, I have two ongoing issues that I cannot figure out:

1.  When "switching" the NEXRAD layers, the image appears to "blink". 
When I use the CIA factbook base layer, this behavior seems to 
disappear.  Note, when I switch layers I enable the new layer, then 
disable the old layer (not vice-versa).

2.  On the http://www.otg-nc.com/csc/index1.html example, if you click 
on a plane you'll see some feature information displayed in a popup. 
However, in some cases, you'll notice the angle of the plane gets messed 
up until its redrawn.

Any ideas on how to fix these?

Kudos to you on the patch Andreas!

thanks

chander


> Hey,
>

> map = new OpenLayers.Map('map');
> var ol_wms = new OpenLayers.Layer.WMS( "Metacarta Basic Layer",
>                                             
> "http://labs.metacarta.com/wms/vmap0",
>                                             {layers: 'basic'} );
> ol_wms.maxExtent = new OpenLayers.Bounds(-125, 17.84, -59, 52.55);
> ol_wms.displayOutsideMaxExtent = true;
> var planes=new OpenLayers.Layer.Vector("Planes",
>             {
>             styleMap: new OpenLayers.StyleMap({
>                        "default": {
>                                     externalGraphic: "../img/marker.png",
>                                     graphicWidth: 24,
>                                     graphicHeight: 28,
>                                     graphicYOffset: 0,
>                                     rotation: "${angle}",
>                                     fillOpacity: "${opacity}"
>                                    }
>                        })
>             });
>
> map.addLayers([ ol_wms , planes ]);
> map.zoomToMaxExtent();
>
> var extent = planes.map.getExtent();
> var yspan = extent.getHeight();
> var xspan = extent.getWidth();
> var x = extent.left + xspan * Math.random();
> var y = extent.top - yspan * Math.random();
> var planeangle = Math.floor(Math.random() * 360);
> var feature=new OpenLayers.Feature.Vector(
>    new OpenLayers.Geometry.Point(x, y), {
>        "angle": planeangle,
>        opacity: 100
>    });
> planes.addFeatures([feature]);
>
>
> Regards,
> Andreas.
>
> Chander Ganesan wrote:
>> Hi,
>>
>> Give some advice by crschmidt on #openlayers, I tried to apply the 
>> patch specified in ticket #1433 to my installation of OpenLayer, and 
>> then tried to create a point with an externalGraphic and rotation 
>> angle.  Unfortunately, this doesn't seem to work.  Here's the code 
>> that I used:
>>
>> map = new OpenLayers.Map('map');
>> var ol_wms = new OpenLayers.Layer.WMS( "Metacarta Basic Layer",
>>                                              
>> "http://labs.metacarta.com/wms/vmap0",
>>                                              {layers: 'basic'} );
>> ol_wms.maxExtent = new OpenLayers.Bounds(-125, 17.84, -59, 52.55);
>> ol_wms.displayOutsideMaxExtent = true;
>> var planes=new OpenLayers.Layer.Vector("Planes",
>>              {
>>              styleMap: new OpenLayers.StyleMap({ 
>>                         "default": { 
>>                                      externalGraphic: "airplane.gif", 
>>                                      graphicWidth: 24, 
>>                                      graphicHeight: 28, 
>>                                      graphicYOffset: 0, 
>>                                      rotation: "${angle}", 
>>                                      fillOpacity: "${opacity}" 
>>                                     }
>>                         })
>>              });
>>
>> var extent = planes.map.getExtent();
>> var yspan = extent.getHeight();
>> var xspan = extent.getWidth();
>> var x = extent.left + xspan * Math.random();
>> var y = extent.top - yspan * Math.random();
>> var planeangle = Math.floor(Math.random() * 360);
>> var feature=new OpenLayers.Feature.Vector( new 
>> OpenLayers.Geometry.Point(x, y), {"angle": planeangle, 
>>                                                                                  
>> opacity: 100 });
>> map.addLayers([ ol_wms , planes ]);
>> map.zoomToMaxExtent();
>>
>>
>> This code causes the layer to draw with the US map underneath, and 
>> the plane image to appear on the layer, but the image is not 
>> rotated.  Any ideas/thoughts?
>>
>> thanks
>>
>> chander
>> _______________________________________________
>> Users mailing list
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>> http://openlayers.org/mailman/listinfo/users
>>   
>


-- 
Chander Ganesan
Open Technology Group, Inc.
One Copley Parkway, Suite 210
Morrisville, NC  27560
919-463-0999/877-258-8987
http://www.otg-nc.com