On Wed, Mar 16, 2011 at 5:12 PM, Bryan Stevenson wrote: > I'm wondering if anyone has any advice on performing a task that > involves determining if a given lat/long is within a given oddly shaped > (not a simple rectangle) area/box?
Where do the point and the polygon originate and in which way are they described? In most cases I have dealt with the point was based on user input and the polygon was in some server side dataset. In that case it is just a matter of storing the polygon in a proper format like WKB or whatever geometric datatype your database offers and using the API's or SQL operators provided to do the comparison. > I would assume the hard part is defining the boundaries of an irregular > shaped box, but once defined the check to see if the co-ordinates are > within it is probably more straightforward. Typically you define your shapes by the coordinates of the series of points that make up the edge. Then you first get a simple (indexable in a proper database) comparison to see if your point is a potential match (between min/max of long/lat). Followed by more complex math to see if it is a proper match. For instance a crescent shape has lots of points between the minimum and maximum that still don't overlap. The latter comparison is something you definitely don't want to implement yourself. Jochem -- Jochem van Dieten http://jochem.vandieten.net/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Order the Adobe Coldfusion Anthology now! http://www.amazon.com/Adobe-Coldfusion-Anthology/dp/1430272155/?tag=houseoffusion Archive: http://www.houseoffusion.com/groups/cf-talk/message.cfm/messageid:343086 Subscription: http://www.houseoffusion.com/groups/cf-talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/groups/cf-talk/unsubscribe.cfm
