getting correct Lat and Lon for all 4 corners of a map

[alleyoop]

I am trying to write a viewer app in html/ Jscipt/vbscript
That creates a lon/lat calibration file for any clipboard captuer. I can do everything ok except I cant find the best lat and long value for each o the 4 corners. I have tried the MGExtent to get the max-min X's and the max-min Y's but these only give 2 corners and I have not been able to calculate the other two corners very accurately. It seems to me there should be an easier or at least a more accurate way to do this? Can anyone hep me?
Thanks very much!
Alley

[CityOfRiponGIS]

I'd just use the MGExtent. By finding the max's and min's you are finding all 4 corners. just use the right combinations of them for the corners.

Top Left Corner = (Min X, Max Y)
Top Right Corner = (Max X, Max Y)
Bottom Right Corner = (Min X, Max Y)
Bottom Left Corner= (Min X, Min Y)

Good Luck!

Andrew Malizia