Comments on: More Overlay Example Code Available

By: Jeremy

Jeremy — Thu, 30 Jul 2009 04:42:24 +0000

@Randy

Cool, glad to hear you got the examples working!

By: Randy

Randy — Wed, 29 Jul 2009 20:46:23 +0000

I got the pure AS3 example to compile in Flex as an AS3 project; however, flex wouldn’t allow the Hotspots class to access the DEFAULT_SCENE_DIMENSION var of the IMultiScaleContainer (it’s a protected constant). I just replaced it with the constant value provided in the IMultiScaleContainer class and it ran ok. I’m just not sure why the example compiles ok in Flash CS3 with that error. I am still going to try extending these classes so they compile within a Flex project, maybe as a component.

Thanks again,
Randy

By: Randy

Randy — Wed, 29 Jul 2009 19:50:33 +0000

Thanks for the response, Jeremy. I will try modifying the overlay classes and let you know if I have any success.

By: Jeremy

Jeremy — Tue, 28 Jul 2009 00:55:42 +0000

Hi Randy,

In order to use the the overlay extension within a Flex project you would most likely need to modify the overlay classes to extend UIComponent. I have yet to try this myself only because I haven’t had the need for OpenZoom + Flex. If you find yourself doing so, let me know and maybe we can add it to the code-base!

There is a download available from the google code project site that doesn’t require the Flash IDE ( all graphics are embedded ). So, If you are looking to compile a pure ActionScript 3.0 version be sure to check that out too.

Thanks,
~Jeremy

By: Randy

Randy — Mon, 27 Jul 2009 22:02:57 +0000

This is really great stuff. Can I compile these code examples in Flex using an actionscript project (i understand that would probably have to convert any linked movieclips for use in)? Or do you have an example of using overlays with the openzoom flex MultiscaleImage component?

By: Hyder Alamgir

Hyder Alamgir — Mon, 18 May 2009 20:46:17 +0000

Oh and don’t forget

marker.x = pixelX * map.sceneWidth;
marker.y = pixelY * map.sceneHeight;

By: Hyder Alamgir

Hyder Alamgir — Mon, 18 May 2009 20:42:23 +0000

For anyone interested, here’s the code to convert lat,lng to x,y coordinates on the openzoom map.

sinLat = Math.sin(latitude * Math.PI / 180 );
pixelX = (longitude + 180 ) / 360;
pixelY = ( .5 – Math.log(( 1 + sinLat ) / ( 1 – sinLat )) / ( 4 * Math.PI ));

Tried and tested on openstreetmap api, but haven’t used your overlay component yet, was using Daniel’s openzoom markers.

By: Ghost Interactive

Ghost Interactive — Tue, 21 Apr 2009 01:27:45 +0000

The overlay extension is made to work with the OpenZoom MultiScaleImage only. Integration with actual mapping software is not the core focus. There is some cool software out there though that allows you to place custom overlays in latlng coordinates. Have you checked out ModestMaps or UMap.
Here are a couple of links that might point you in the right direction.
http://modestmaps.com/
http://www.afcomponents.com/components/umap_as3/

Thanks for your interest!
~Jeremy

By: Hyder Alamgir

Hyder Alamgir — Tue, 21 Apr 2009 01:13:35 +0000

Great overlays! But I’d like to use in my OpenStreetMap project, how soon can you get projection calculations done to get that implemented.

Ideally, I’d like to it be able parse latlng values directly.

I know Google uses the Mercator Projection, you can find some Math on it at Wikipedia:

http://en.wikipedia.org/wiki/Mercator_projection