Zoom By Scale

[jonataspovoas]

Hi,

I have a map service that has esriDecimalDegrees units, and I need to calculate wicth scale it is so I can zoom to scale.

My problem is that I can't find the factor to the esri units type, to fill the equasion above:

Map scale = 1 : (ScreenRes pixels/inch * 39.37 inches/meter * (Map.Resolution * conversionFactorToMeters))

Where can i find these convertion factors?

[DominiqueBroux]

As your map is in decimal degress, the conversion factor is the number of meters for one degree, i.e about 111320 ( 2 * PI * earthRadius / 360)