Setting Feature Layer maxAllowableOffset property

Derek Swingley from ESRI recently enlightened me on the use of feature layers for the ArcGIS APIs for Flex, JavaScript, and Silverlight.

Max Allowable Offset basically determines the level of geometry generalization when returned from the mapping server.  The larger the offset, the greater the simplification.  To calculate the appropriate maxAllowableOffset, I am simply using the ground resolution of the current zoom level of the map (AS3):

private const EARTH_CIRCUM:Number = 2 * 3.14159265 * 6378137;
private function computeAllowableOffset():void
{
    fLayer.maxAllowableOffset = (EARTH_CIRCUM / (256 * Math.pow(2, oMap.level)));
}

If you are using a WGS84 Basemap, you can just divide the result above by the number of meters per degree:

private const EARTH_CIRCUM:Number = 2 * 3.14159265 * 6378137;
private function computeAllowableOffset():void
{
    fLayer.maxAllowableOffset = (EARTH_CIRCUM / (256 * Math.pow(2, oMap.level))) / (EARTH_CIRCUM / 360);
}

These functions make it so that at the equator there should only be one vertex per pixel. I've been wanting a little more stylized features, so I've been adding about 35 - 40% additional offset:

private const EARTH_CIRCUM:Number = 2 * 3.14159265 * 6378137;
private function computeAllowableOffset():void
{
    fLayer.maxAllowableOffset = (EARTH_CIRCUM / (256 * Math.pow(2, oMap.level))) * 1.35;
}

For more information on feature layers, check out Derek's blog posts