The resolution is units per pixel. if you want a point with a radius of 20km = 20000m, then you can calculate the radius in pixel = 20000 / actual resolution. Instead of a point feature, you can also take a regular polygon with ie. 20 sides to get a circle. Then the radius have to be in units of the map and as it is a geometric object, it changes the size with zoom.
Arnd Wippermann _____ Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Chris Streeter Gesendet: Freitag, 10. Oktober 2008 19:09 An: [email protected] Betreff: Re: [OpenLayers-Users] Dynamically Sized Points With Styles As a followup to this question, I'm trying to wrap my head around how to translate actual distances to what is shown on the map. For example, if I wanted to create a feature with a radius of 20 kilometers, how do I specify the radius for the feature based on the map's resolution and scale. I'm not quite clear on how feature radii relate to map resolution and scale. Thanks, - Chris On Wed, Oct 8, 2008 at 11:49, Arnd Wippermann <[EMAIL PROTECTED]> wrote: http://n2.nabble.com/GML%2C-Point-and-Change-the-Size-of-the-Circle...-tc791 275.html#a791275 listen to the zoom event and redraw the feature with the new styleMap, where the pointRadius is a function of the zoom level: new OpenLayers.StyleMap({ "default": OpenLayers.Util.applyDefaults({ pointRadius: faktor*map.getZoom() }, OpenLayers.Feature.Vector.style["default"] }); Arnd Wippermann _____ Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Chris Streeter Gesendet: Mittwoch, 8. Oktober 2008 07:04 An: [email protected] Betreff: [OpenLayers-Users] Dynamically Sized Points With Styles I was wondering if it is possible to dynamically resize a point based on the zoom level of the map. With the example at http://www.openlayers.org/dev/examples/styles-unique.html, can we make the points change their radius as we zoom in? I'd like to keep the circles the same relative size to the underlying map layer. Thanks, - Chris
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